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PetSet examples

Clayton Coleman authored on 2016/06/18 03:12:32
Showing 33 changed files
examples/pets/README.md
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+# PetSet examples
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+
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+These examples are tracked from the [Kubernetes contrib project @d6e4be](https://github.com/kubernetes/contrib/tree/d6e4be066cc076fbb91ff69691819e117711b30b/pets)
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+
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+Note that some of these examples require the ability to run root containers which may not be possible for all users in all environments. To grant
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+access to run containers as root to a service account in your project, run:
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+
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+    oadm policy add-scc-to-user anyuid -z default
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+
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+which allows the `default` service account to run root containers.
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\ No newline at end of file
examples/pets/mysql/galera/README.md
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+# Mysql Galera
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+
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+This example runs mysql galera through a petset.
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+
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+## Bootstrap
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+
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+Create the petset in this directory
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+```
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+$ kubectl create -f galera.yaml
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+```
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+
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+Once you have all 3 nodes in Running, you can run the "test.sh" script in this directory.
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+This example requires manual intervention.
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+Once you have all 3 nodes in Running, you can run the "test.sh" script in this directory.
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+
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+## Caveats
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+
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+Starting up all galera nodes at once leads to an issue where all the mysqls
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+belive they're in the primary component because they don't see the others in
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+the DNS. For the bootstrapping to work: mysql-0 needs to see itself, mysql-1
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+needs to see itself and mysql-0, and so on, because the first node that sees
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+a peer list of 1 will assume it's the leader.
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+
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+## TODO
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+
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+Expect better solutions for the following as petset matures.
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+
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+* Failover
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+* Scaling Up
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+* Scaling Down
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+* Image Upgrade
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+* Maintenance
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+
examples/pets/mysql/galera/init/Dockerfile
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+# Copyright 2016 The Kubernetes Authors All rights reserved.
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+#
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+# Licensed under the Apache License, Version 2.0 (the "License");
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+# you may not use this file except in compliance with the License.
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+# You may obtain a copy of the License at
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+#
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+#     http://www.apache.org/licenses/LICENSE-2.0
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+#
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+# Unless required by applicable law or agreed to in writing, software
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+# distributed under the License is distributed on an "AS IS" BASIS,
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+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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+# See the License for the specific language governing permissions and
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+# limitations under the License.
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+
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+# TODO: get rid of bash dependency and switch to plain busybox.
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+# The tar in busybox also doesn't seem to understand compression.
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+FROM debian:jessie
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+MAINTAINER Prashanth.B <beeps@google.com>
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+
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+RUN apt-get update && apt-get install -y wget
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+
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+ADD on-start.sh /
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+ADD my-galera.cnf /
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+# See contrib/pets/peer-finder for details
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+RUN wget -qO /peer-finder https://storage.googleapis.com/kubernetes-release/pets/peer-finder
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+
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+ADD install.sh /
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+RUN chmod -c 755 /install.sh /on-start.sh /peer-finder
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+Entrypoint ["/install.sh"]
examples/pets/mysql/galera/init/Makefile
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+# Copyright 2016 The Kubernetes Authors All rights reserved.
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+#
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+# Licensed under the Apache License, Version 2.0 (the "License");
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+# you may not use this file except in compliance with the License.
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+# You may obtain a copy of the License at
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+#
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+#     http://www.apache.org/licenses/LICENSE-2.0
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+#
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+# Unless required by applicable law or agreed to in writing, software
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+# distributed under the License is distributed on an "AS IS" BASIS,
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+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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+# See the License for the specific language governing permissions and
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+# limitations under the License.
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+
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+all: push
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+
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+TAG = 0.1
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+PREFIX = gcr.io/google_containers/galera-install
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+
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+container:
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+	docker build -t $(PREFIX):$(TAG) .
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+
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+push: container
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+	gcloud docker push $(PREFIX):$(TAG)
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+
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+clean:
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+	docker rmi $(PREFIX):$(TAG)
examples/pets/mysql/galera/init/install.sh
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+#! /bin/bash
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+
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+# Copyright 2016 The Kubernetes Authors All rights reserved.
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+#
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+# Licensed under the Apache License, Version 2.0 (the "License");
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+# you may not use this file except in compliance with the License.
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+# You may obtain a copy of the License at
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+#
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+#     http://www.apache.org/licenses/LICENSE-2.0
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+#
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+# Unless required by applicable law or agreed to in writing, software
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+# distributed under the License is distributed on an "AS IS" BASIS,
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+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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+# See the License for the specific language governing permissions and
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+# limitations under the License.
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+
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+# This volume is assumed to exist and is shared with parent of the init
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+# container. It contains the mysq config.
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+CONFIG_VOLUME="/etc/mysql"
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+
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+# This volume is assumed to exist and is shared with the peer-finder
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+# init container. It contains on-start/change configuration scripts.
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+WORKDIR_VOLUME="/work-dir"
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+
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+for i in "$@"
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+do
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+case $i in
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+    -c=*|--config=*)
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+    CONFIG_VOLUME="${i#*=}"
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+    shift
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+    ;;
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+    -w=*|--work-dir=*)
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+    WORKDIR_VOLUME="${i#*=}"
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+    shift
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+    ;;
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+    *)
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+    # unknown option
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+    ;;
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+esac
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+done
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+
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+echo installing config scripts into "${WORKDIR_VOLUME}"
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+mkdir -p "${WORKDIR_VOLUME}"
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+cp /on-start.sh "${WORKDIR_VOLUME}"/
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+cp /peer-finder "${WORKDIR_VOLUME}"/
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+
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+echo installing my-galera.cnf into "${CONFIG_VOLUME}"
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+mkdir -p "${CONFIG_VOLUME}"
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+chown -R mysql:mysql "${CONFIG_VOLUME}"
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+cp /my-galera.cnf "${CONFIG_VOLUME}"/
examples/pets/mysql/galera/init/my-galera.cnf
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+[mysqld]
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+user = mysql
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+bind-address = 0.0.0.0
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+wsrep_provider = /usr/lib/galera/libgalera_smm.so
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+# TODO: is rsync the best option?
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+wsrep_sst_method = rsync
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+default_storage_engine = innodb
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+binlog_format = row
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+innodb_autoinc_lock_mode = 2
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+innodb_flush_log_at_trx_commit = 0
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+query_cache_size = 0
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+query_cache_type = 0
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+
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+# By default every node is standalone
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+wsrep_cluster_address=gcomm://
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+wsrep_cluster_name=galera
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+wsrep_node_address=127.0.0.1
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+
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+# TODO: Enable use privileges. This doesn't work
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+# on mysql restart, for some reason after the SST
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+# permissions are not setup correctly.
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+skip-grant-tables
examples/pets/mysql/galera/init/on-start.sh
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+#! /bin/bash
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+
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+# Copyright 2016 The Kubernetes Authors All rights reserved.
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+#
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+# Licensed under the Apache License, Version 2.0 (the "License");
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+# you may not use this file except in compliance with the License.
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+# You may obtain a copy of the License at
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+#
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+#     http://www.apache.org/licenses/LICENSE-2.0
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+#
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+# Unless required by applicable law or agreed to in writing, software
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+# distributed under the License is distributed on an "AS IS" BASIS,
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+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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+# See the License for the specific language governing permissions and
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+# limitations under the License.
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+
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+# This script writes out a mysql galera config using a list of newline seperated
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+# peer DNS names it accepts through stdin.
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+
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+# /etc/mysql is assumed to be a shared volume so we can modify my.cnf as required
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+# to keep the config up to date, without wrapping mysqld in a custom pid1.
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+# The config location is intentionally not /etc/mysql/my.cnf because the
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+# standard base image clobbers that location.
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+CFG=/etc/mysql/my-galera.cnf
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+
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+function join {
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+    local IFS="$1"; shift; echo "$*";
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+}
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+
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+HOSTNAME=$(hostname)
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+# Parse out cluster name, formatted as: petset_name-index
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+IFS='-' read -ra ADDR <<< "$(hostname)"
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+CLUSTER_NAME="${ADDR[0]}"
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+
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+while read -ra LINE; do
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+    if [[ "${LINE}" == *"${HOSTNAME}"* ]]; then
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+        MY_NAME=$LINE
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+    fi
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+    PEERS=("${PEERS[@]}" $LINE)
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+done
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+
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+if [ "${#PEERS[@]}" = 1 ]; then
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+    WSREP_CLUSTER_ADDRESS=""
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+else
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+    WSREP_CLUSTER_ADDRESS=$(join , "${PEERS[@]}")
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+fi
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+sed -i -e "s|^wsrep_node_address=.*$|wsrep_node_address=${MY_NAME}|" ${CFG}
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+sed -i -e "s|^wsrep_cluster_name=.*$|wsrep_cluster_name=${CLUSTER_NAME}|" ${CFG}
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+sed -i -e "s|^wsrep_cluster_address=.*$|wsrep_cluster_address=gcomm://${WSREP_CLUSTER_ADDRESS}|" ${CFG}
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+
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+# don't need a restart, we're just writing the conf in case there's an
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+# unexpected restart on the node.
examples/pets/mysql/galera/mysql-galera.yaml
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+# A headless service to create DNS records
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+apiVersion: v1
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+kind: Service
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+metadata:
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+  annotations:
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+    service.alpha.kubernetes.io/tolerate-unready-endpoints: "true"
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+  name: galera
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+  labels:
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+    app: mysql
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+spec:
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+  ports:
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+  - port: 3306
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+    name: mysql
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+  # *.galear.default.svc.cluster.local
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+  clusterIP: None
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+  selector:
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+    app: mysql
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+---
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+apiVersion: apps/v1alpha1
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+kind: PetSet
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+metadata:
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+  name: mysql
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+spec:
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+  serviceName: "galera"
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+  replicas: 3
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+  template:
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+    metadata:
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+      labels:
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+        app: mysql
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+      annotations:
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+        pod.alpha.kubernetes.io/initialized: "true"
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+        pod.alpha.kubernetes.io/init-containers: '[
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+            {
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+                "name": "install",
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+                "image": "gcr.io/google_containers/galera-install:0.1",
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+                "imagePullPolicy": "Always",
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+                "args": ["--work-dir=/work-dir"],
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+                "volumeMounts": [
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+                    {
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+                        "name": "workdir",
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+                        "mountPath": "/work-dir"
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+                    },
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+                    {
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+                        "name": "config",
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+                        "mountPath": "/etc/mysql"
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+                    }
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+                ]
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+            },
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+            {
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+                "name": "bootstrap",
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+                "image": "debian:jessie",
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+                "command": ["/work-dir/peer-finder"],
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+                "args": ["-on-start=\"/work-dir/on-start.sh\"", "-service=galera"],
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+                "env": [
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+                  {
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+                      "name": "POD_NAMESPACE",
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+                      "valueFrom": {
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+                          "fieldRef": {
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+                              "apiVersion": "v1",
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+                              "fieldPath": "metadata.namespace"
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+                          }
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+                      }
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+                   }
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+                ],
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+                "volumeMounts": [
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+                    {
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+                        "name": "workdir",
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+                        "mountPath": "/work-dir"
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+                    },
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+                    {
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+                        "name": "config",
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+                        "mountPath": "/etc/mysql"
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+                    }
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+                ]
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+            }
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+        ]'
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+    spec:
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+      containers:
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+      - name: mysql
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+        image: erkules/galera:basic
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+        ports:
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+        - containerPort: 3306
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+          name: mysql
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+        - containerPort: 4444
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+          name: sst
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+        - containerPort: 4567
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+          name: replication
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+        - containerPort: 4568
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+          name: ist
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+        args:
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+        - --defaults-file=/etc/mysql/my-galera.cnf
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+        - --user=root
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+        readinessProbe:
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+          exec:
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+            command:
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+            - sh
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+            - -c
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+            - "mysql -u root -e 'show databases;'"
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+          initialDelaySeconds: 15
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+          timeoutSeconds: 5
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+        volumeMounts:
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+        - name: datadir
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+          mountPath: /var/lib/
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+        - name: config
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+          mountPath: /etc/mysql
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+      volumes:
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+      - name: config
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+        emptyDir: {}
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+      - name: workdir
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+        emptyDir: {}
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+  volumeClaimTemplates:
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+  - metadata:
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+      name: datadir
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+      annotations:
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+        volume.alpha.kubernetes.io/storage-class: anything
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+    spec:
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+      accessModes: [ "ReadWriteOnce" ]
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+      resources:
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+        requests:
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+          storage: 10Gi
examples/pets/mysql/galera/test.sh
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+#! /bin/bash
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+
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+# Copyright 2016 The Kubernetes Authors All rights reserved.
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+#
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+# Licensed under the Apache License, Version 2.0 (the "License");
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+# you may not use this file except in compliance with the License.
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+# You may obtain a copy of the License at
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+#
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+#     http://www.apache.org/licenses/LICENSE-2.0
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+#
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+# Unless required by applicable law or agreed to in writing, software
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+# distributed under the License is distributed on an "AS IS" BASIS,
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+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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+# See the License for the specific language governing permissions and
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+# limitations under the License.
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+
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+kubectl exec mysql-0 -- mysql -u root -e "create database test;"
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+kubectl exec mysql-1 -- mysql -u root -e "use test; create table pet (id int(10), name varchar(20));"
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+kubectl exec mysql-1 -- mysql -u root -e "use test; insert into pet (id, name) values (1, \"galera\");"
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+kubectl exec mysql-2 -- mysql -u root -e "use test; select * from pet;"
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+
examples/pets/mysql/healthz/Dockerfile
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+# Copyright 2016 The Kubernetes Authors All rights reserved.
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+#
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+# Licensed under the Apache License, Version 2.0 (the "License");
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+# you may not use this file except in compliance with the License.
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+# You may obtain a copy of the License at
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+#
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+#     http://www.apache.org/licenses/LICENSE-2.0
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+#
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+# Unless required by applicable law or agreed to in writing, software
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+# distributed under the License is distributed on an "AS IS" BASIS,
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+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11 
+# See the License for the specific language governing permissions and
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+# limitations under the License.
13 
+
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+# TODO: get rid of bash dependency and switch to plain busybox.
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+# The tar in busybox also doesn't seem to understand compression.
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+FROM debian:jessie
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+MAINTAINER Prashanth.B <beeps@google.com>
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+
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+RUN apt-get update && apt-get install -y mysql-client wget
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+ADD mysql_healthz /mysql_healthz
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+Entrypoint ["/mysql_healthz"]
examples/pets/mysql/healthz/Makefile
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+# Copyright 2016 The Kubernetes Authors All rights reserved.
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+#
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+# Licensed under the Apache License, Version 2.0 (the "License");
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+# you may not use this file except in compliance with the License.
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+# You may obtain a copy of the License at
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+#
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+#     http://www.apache.org/licenses/LICENSE-2.0
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+#
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+# Unless required by applicable law or agreed to in writing, software
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+# distributed under the License is distributed on an "AS IS" BASIS,
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+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11 
+# See the License for the specific language governing permissions and
12 
+# limitations under the License.
13 
+
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+all: push
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+
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+# 0.0 shouldn't clobber any released builds
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+TAG = 0.1
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+PREFIX = gcr.io/google_containers/mysql-healthz
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+
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+server: main.go
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+	CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -ldflags '-w' -o mysql_healthz ./main.go
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+
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+container: server
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+	docker build -t $(PREFIX):$(TAG) .
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+
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+push: container
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+	gcloud docker push $(PREFIX):$(TAG)
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+
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+clean:
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+	rm -f mysql_healthz
examples/pets/mysql/healthz/README.md
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+# Mysql healthz
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+
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+This is a simple exec-over-http healthz probe for mysql. Mainly intended as a work-around for (#25456)[https://github.com/kubernetes/kubernetes/issues/25456].
examples/pets/mysql/healthz/main.go
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+/*
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+Copyright 2015 The Kubernetes Authors All rights reserved.
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+
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+Licensed under the Apache License, Version 2.0 (the "License");
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+you may not use this file except in compliance with the License.
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+You may obtain a copy of the License at
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+
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+    http://www.apache.org/licenses/LICENSE-2.0
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+
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+Unless required by applicable law or agreed to in writing, software
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+distributed under the License is distributed on an "AS IS" BASIS,
11 
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 
+See the License for the specific language governing permissions and
13 
+limitations under the License.
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+*/
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+
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+// This is a simple health monitor for mysql. Only needed till #25456 is fixed.
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+package main
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+
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+import (
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+	"fmt"
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+	"log"
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+	"net/http"
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+	"os"
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+	osExec "os/exec"
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+	"strings"
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+
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+	flag "github.com/spf13/pflag"
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+)
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+
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+var (
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+	flags   = flag.NewFlagSet("a http healthz server for mysql.", flag.ExitOnError)
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+	port    = flags.Int("port", 8080, "port to use for healthz server.")
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+	verbose = flags.Bool("verbose", false, "log verbose output?")
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+	pass    = flags.String("password", "", "mysql password.")
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+	host    = flags.String("host", "", "mysql host.")
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+
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+	mysqlChecks = map[string]string{
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+		"/healthz": "show databases;",
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+	}
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+)
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+
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+type mysqlManager struct {
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+	host, pass string
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+}
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+
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+func (m *mysqlManager) exec(cmd string) ([]byte, error) {
47 
+	var password string
48 
+	if m.pass != "" {
49 
+		password = fmt.Sprintf("-p %v", m.pass)
50 
+	}
51 
+	mysqlCmd := fmt.Sprintf("/usr/bin/mysql -u root %v -h %v -B -e '%v'", password, m.host, cmd)
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+	return osExec.Command("sh", "-c", mysqlCmd).CombinedOutput()
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+}
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+
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+func registerHandlers(verbose bool, m *mysqlManager) {
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+	var str string
57 
+	for endpoint, cmd := range mysqlChecks {
58 
+		str += fmt.Sprintf("\t%v: %q\n", endpoint, cmd)
59 
+		http.HandleFunc(endpoint, func(w http.ResponseWriter, r *http.Request) {
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+			output, err := m.exec(cmd)
61 
+			if err != nil {
62 
+				w.WriteHeader(http.StatusServiceUnavailable)
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+			} else {
64 
+				w.WriteHeader(http.StatusOK)
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+			}
66 
+			if verbose {
67 
+				log.Printf("Output of %v:\n%v\n", cmd, string(output))
68 
+			}
69 
+			w.Write(output)
70 
+		})
71 
+	}
72 
+	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
73 
+		w.WriteHeader(http.StatusOK)
74 
+		w.Write([]byte(fmt.Sprintf("Available handlers:\n%v", str)))
75 
+	})
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+}
77 
+
78 
+func getHostnameOrDie() string {
79 
+	output, err := osExec.Command("hostname").CombinedOutput()
80 
+	if err != nil {
81 
+		log.Fatalf("%v", err)
82 
+	}
83 
+	return strings.Trim(string(output), "\n")
84 
+}
85 
+
86 
+func main() {
87 
+	flags.Parse(os.Args)
88 
+	hostname := *host
89 
+	if hostname == "" {
90 
+		hostname = getHostnameOrDie()
91 
+	}
92 
+	registerHandlers(*verbose, &mysqlManager{pass: *pass, host: hostname})
93 
+	log.Printf("Starting mysql healthz server on port %v", *port)
94 
+	log.Fatalf(fmt.Sprintf("%v", http.ListenAndServe(fmt.Sprintf(":%v", *port), nil)))
95 
+}
examples/pets/mysql/healthz/pod.yaml
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@@ -0,0 +1,19 @@
0 
+apiVersion: v1
1 
+kind: Pod
2 
+metadata:
3 
+  name: mysql
4 
+  namespace: default
5 
+spec:
6 
+  containers:
7 
+  - image: mysql:5.6
8 
+    name: server
9 
+    env:
10 
+    - name: MYSQL_ALLOW_EMPTY_PASSWORD
11 
+      value: "yes"
12 
+    readinessProbe:
13 
+      httpGet:
14 
+        path: /healthz
15 
+        port: 8080
16 
+  - name: healthz
17 
+    image: gcr.io/google_containers/mysql-healthz:1.0
18 
+    imagePullPolicy: Always
examples/pets/peer-finder/Dockerfile
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0 
+# Copyright 2016 The Kubernetes Authors All rights reserved.
1 
+#
2 
+# Licensed under the Apache License, Version 2.0 (the "License");
3 
+# you may not use this file except in compliance with the License.
4 
+# You may obtain a copy of the License at
5 
+#
6 
+#     http://www.apache.org/licenses/LICENSE-2.0
7 
+#
8 
+# Unless required by applicable law or agreed to in writing, software
9 
+# distributed under the License is distributed on an "AS IS" BASIS,
10 
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11 
+# See the License for the specific language governing permissions and
12 
+# limitations under the License.
13 
+
14 
+FROM gcr.io/google_containers/ubuntu-slim:0.2
15 
+MAINTAINER Prashanth.B <beeps@google.com>
16 
+
17 
+RUN apt-get update && apt-get install -y wget bash dnsutils
18 
+ADD peer-finder /peer-finder
19 
+ADD peer-finder.go /peer-finder.go
20 
+
21 
+EXPOSE 9376
22 
+ENTRYPOINT ["/peer-finder"]
examples/pets/peer-finder/Makefile
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0 
+# Copyright 2016 The Kubernetes Authors All rights reserved.
1 
+#
2 
+# Licensed under the Apache License, Version 2.0 (the "License");
3 
+# you may not use this file except in compliance with the License.
4 
+# You may obtain a copy of the License at
5 
+#
6 
+#     http://www.apache.org/licenses/LICENSE-2.0
7 
+#
8 
+# Unless required by applicable law or agreed to in writing, software
9 
+# distributed under the License is distributed on an "AS IS" BASIS,
10 
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11 
+# See the License for the specific language governing permissions and
12 
+# limitations under the License.
13 
+
14 
+all: push
15 
+
16 
+TAG = 0.1
17 
+PREFIX = gcr.io/google_containers/peer-finder
18 
+
19 
+server: peer-finder.go
20 
+	CGO_ENABLED=0 go build -a -installsuffix cgo --ldflags '-w' ./peer-finder.go
21 
+
22 
+release: server
23 
+	gsutil cp peer-finder gs://kubernetes-release/pets/peer-finder
24 
+
25 
+container: server
26 
+	docker build -t $(PREFIX):$(TAG) .
27 
+
28 
+push: container
29 
+	gcloud docker push $(PREFIX):$(TAG)
30 
+
31 
+clean:
32 
+	rm -f peer-finder
examples/pets/peer-finder/README.md
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0 
+# Peer finder
1 
+
2 
+This is a simple peer finder daemon that runs as pid 1 in a petset.
3 
+It is expected to be a temporary solution till the main Kubernetes repo supports:
4 
+1. Init containers to replace on-start scripts
5 
+2. A notification delivery mechanism that allows external controllers to
6 
+   declaratively execute on-change scripts in containers.
7 
+
8 
+Though we don't expect this container to always run as pid1, it will be
9 
+necessary in some form. All it does is resolve DNS. Even when we get (2)
10 
+the most natural way to update the input for the on-change script is through
11 
+a sidecar that runs the peer-finder.
12 
+
13 
+
14 
+
examples/pets/peer-finder/peer-finder.go
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0 
+/*
1 
+Copyright 2014 The Kubernetes Authors All rights reserved.
2 
+
3 
+Licensed under the Apache License, Version 2.0 (the "License");
4 
+you may not use this file except in compliance with the License.
5 
+You may obtain a copy of the License at
6 
+
7 
+    http://www.apache.org/licenses/LICENSE-2.0
8 
+
9 
+Unless required by applicable law or agreed to in writing, software
10 
+distributed under the License is distributed on an "AS IS" BASIS,
11 
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 
+See the License for the specific language governing permissions and
13 
+limitations under the License.
14 
+*/
15 
+
16 
+// A small utility program to lookup hostnames of endpoints in a service.
17 
+package main
18 
+
19 
+import (
20 
+	"flag"
21 
+	"fmt"
22 
+	"log"
23 
+	"net"
24 
+	"os"
25 
+	"os/exec"
26 
+	"sort"
27 
+	"strings"
28 
+	"time"
29 
+
30 
+	"k8s.io/kubernetes/pkg/util/sets"
31 
+)
32 
+
33 
+const (
34 
+	svcLocalSuffix = "svc.cluster.local"
35 
+	pollPeriod     = 1 * time.Second
36 
+)
37 
+
38 
+var (
39 
+	onChange  = flag.String("on-change", "", "Script to run on change, must accept a new line separated list of peers via stdin.")
40 
+	onStart   = flag.String("on-start", "", "Script to run on start, must accept a new line separated list of peers via stdin.")
41 
+	svc       = flag.String("service", "", "Governing service responsible for the DNS records of the domain this pod is in.")
42 
+	namespace = flag.String("ns", "", "The namespace this pod is running in. If unspecified, the POD_NAMESPACE env var is used.")
43 
+)
44 
+
45 
+func lookup(svcName string) (sets.String, error) {
46 
+	endpoints := sets.NewString()
47 
+	_, srvRecords, err := net.LookupSRV("", "", svcName)
48 
+	if err != nil {
49 
+		return endpoints, err
50 
+	}
51 
+	for _, srvRecord := range srvRecords {
52 
+		// The SRV records ends in a "." for the root domain
53 
+		ep := fmt.Sprintf("%v", srvRecord.Target[:len(srvRecord.Target)-1])
54 
+		endpoints.Insert(ep)
55 
+	}
56 
+	return endpoints, nil
57 
+}
58 
+
59 
+func shellOut(sendStdin, script string) {
60 
+	log.Printf("execing: %v with stdin: %v", script, sendStdin)
61 
+	// TODO: Switch to sending stdin from go
62 
+	out, err := exec.Command("bash", "-c", fmt.Sprintf("echo -e '%v' | %v", sendStdin, script)).CombinedOutput()
63 
+	if err != nil {
64 
+		log.Fatalf("Failed to execute %v: %v, err: %v", script, string(out), err)
65 
+	}
66 
+	log.Print(string(out))
67 
+}
68 
+
69 
+func main() {
70 
+	flag.Parse()
71 
+
72 
+	ns := *namespace
73 
+	if ns == "" {
74 
+		ns = os.Getenv("POD_NAMESPACE")
75 
+	}
76 
+	if *svc == "" || ns == "" || (*onChange == "" && *onStart == "") {
77 
+		log.Fatalf("Incomplete args, require -on-change and/or -on-start, -service and -ns or an env var for POD_NAMESPACE.")
78 
+	}
79 
+
80 
+	hostname, err := os.Hostname()
81 
+	if err != nil {
82 
+		log.Fatalf("Failed to get hostname: %s", err)
83 
+	}
84 
+
85 
+	myName := strings.Join([]string{hostname, *svc, ns, svcLocalSuffix}, ".")
86 
+	script := *onStart
87 
+	if script == "" {
88 
+		script = *onChange
89 
+		log.Printf("No on-start supplied, on-change %v will be applied on start.", script)
90 
+	}
91 
+	for newPeers, peers := sets.NewString(), sets.NewString(); script != ""; time.Sleep(pollPeriod) {
92 
+		newPeers, err = lookup(*svc)
93 
+		if err != nil {
94 
+			log.Printf("%v", err)
95 
+			continue
96 
+		}
97 
+		if newPeers.Equal(peers) || !newPeers.Has(myName) {
98 
+			continue
99 
+		}
100 
+		peerList := newPeers.List()
101 
+		sort.Strings(peerList)
102 
+		log.Printf("Peer list updated\nwas %v\nnow %v", peers.List(), newPeers.List())
103 
+		shellOut(strings.Join(peerList, "\n"), script)
104 
+		peers = newPeers
105 
+		script = *onChange
106 
+	}
107 
+	// TODO: Exit if there's no on-change?
108 
+	log.Printf("Peer finder exiting")
109 
+}
examples/pets/redis/README.md
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+# Redis
1 
+
2 
+This example runs redis through a petset.
3 
+
4 
+## Master/slave
5 
+
6 
+### Bootstrap
7 
+
8 
+Create the yaml in this directory
9 
+```
10 
+$ kubectl create -f redis.yaml
11 
+```
12 
+
13 
+can run the "test.sh" script in this directory.
14 
+
15 
+## TODO
16 
+
17 
+Expect cleaner solutions for the following as petset matures.
18 
+
19 
+* Scaling Up/down
20 
+* Image Upgrade
21 
+* Periodic maintenance
22 
+* Sentinel failover
examples/pets/redis/init/Dockerfile
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0 
+# Copyright 2016 The Kubernetes Authors All rights reserved.
1 
+#
2 
+# Licensed under the Apache License, Version 2.0 (the "License");
3 
+# you may not use this file except in compliance with the License.
4 
+# You may obtain a copy of the License at
5 
+#
6 
+#     http://www.apache.org/licenses/LICENSE-2.0
7 
+#
8 
+# Unless required by applicable law or agreed to in writing, software
9 
+# distributed under the License is distributed on an "AS IS" BASIS,
10 
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11 
+# See the License for the specific language governing permissions and
12 
+# limitations under the License.
13 
+
14 
+# TODO: get rid of bash dependency and switch to plain busybox.
15 
+# The tar in busybox also doesn't seem to understand compression.
16 
+FROM debian:jessie
17 
+MAINTAINER Prashanth.B <beeps@google.com>
18 
+
19 
+# TODO: just use standard redis when there is one for 3.2.0.
20 
+RUN apt-get update && apt-get install -y wget make gcc
21 
+
22 
+ADD on-start.sh /
23 
+# See contrib/pets/peer-finder for details
24 
+RUN wget -qO /peer-finder https://storage.googleapis.com/kubernetes-release/pets/peer-finder
25 
+
26 
+ADD install.sh /
27 
+RUN chmod -c 755 /install.sh /on-start.sh /peer-finder
28 
+Entrypoint ["/install.sh"]
examples/pets/redis/init/Makefile
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0 
+# Copyright 2016 The Kubernetes Authors All rights reserved.
1 
+#
2 
+# Licensed under the Apache License, Version 2.0 (the "License");
3 
+# you may not use this file except in compliance with the License.
4 
+# You may obtain a copy of the License at
5 
+#
6 
+#     http://www.apache.org/licenses/LICENSE-2.0
7 
+#
8 
+# Unless required by applicable law or agreed to in writing, software
9 
+# distributed under the License is distributed on an "AS IS" BASIS,
10 
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11 
+# See the License for the specific language governing permissions and
12 
+# limitations under the License.
13 
+
14 
+all: push
15 
+
16 
+TAG = 0.1
17 
+PREFIX = gcr.io/google_containers/redis-install
18 
+
19 
+container:
20 
+	docker build -t $(PREFIX):$(TAG) .
21 
+
22 
+push: container
23 
+	gcloud docker push $(PREFIX):$(TAG)
24 
+
25 
+clean:
26 
+	docker rmi $(PREFIX):$(TAG)
examples/pets/redis/init/install.sh
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0 
+#! /bin/bash
1 
+
2 
+# Copyright 2016 The Kubernetes Authors All rights reserved.
3 
+#
4 
+# Licensed under the Apache License, Version 2.0 (the "License");
5 
+# you may not use this file except in compliance with the License.
6 
+# You may obtain a copy of the License at
7 
+#
8 
+#     http://www.apache.org/licenses/LICENSE-2.0
9 
+#
10 
+# Unless required by applicable law or agreed to in writing, software
11 
+# distributed under the License is distributed on an "AS IS" BASIS,
12 
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 
+# See the License for the specific language governing permissions and
14 
+# limitations under the License.
15 
+
16 
+# This volume is assumed to exist and is shared with parent of the init
17 
+# container. It contains the redis installation.
18 
+INSTALL_VOLUME="/opt"
19 
+
20 
+# This volume is assumed to exist and is shared with the peer-finder
21 
+# init container. It contains on-start/change configuration scripts.
22 
+WORK_DIR="/work-dir"
23 
+
24 
+TEMP_DIR="/tmp"
25 
+
26 
+VERSION="3.2.0"
27 
+
28 
+for i in "$@"
29 
+do
30 
+case $i in
31 
+    -v=*|--version=*)
32 
+    VERSION="${i#*=}"
33 
+    shift
34 
+    ;;
35 
+    -i=*|--install-into=*)
36 
+    INSTALL_VOLUME="${i#*=}"
37 
+    shift
38 
+    ;;
39 
+    -w=*|--work-dir=*)
40 
+    WORK_DIR="${i#*=}"
41 
+    shift
42 
+    ;;
43 
+    *)
44 
+    # unknown option
45 
+    ;;
46 
+esac
47 
+done
48 
+
49 
+echo installing config scripts into "${WORK_DIR}"
50 
+mkdir -p "${WORK_DIR}"
51 
+cp /on-start.sh "${WORK_DIR}"/
52 
+cp /peer-finder "${WORK_DIR}"/
53 
+
54 
+echo installing redis-"${VERSION}" into "${INSTALL_VOLUME}"
55 
+mkdir -p "${TEMP_DIR}" "${INSTALL_VOLUME}"/redis
56 
+wget -q -O - http://download.redis.io/releases/redis-"${VERSION}".tar.gz | tar -xzf - -C "${TEMP_DIR}"
57 
+
58 
+cd "${TEMP_DIR}"/redis-"${VERSION}"/
59 
+# Clean out existing deps, see https://github.com/antirez/redis/issues/722
60 
+make distclean
61 
+make install INSTALL_BIN="${INSTALL_VOLUME}"/redis
62 
+cp "${TEMP_DIR}"/redis-"${VERSION}"/redis.conf ${INSTALL_VOLUME}/redis/redis.conf
63 
+
examples/pets/redis/init/on-start.sh
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0 
+#!/bin/bash
1 
+
2 
+# Copyright 2016 The Kubernetes Authors All rights reserved.
3 
+#
4 
+# Licensed under the Apache License, Version 2.0 (the "License");
5 
+# you may not use this file except in compliance with the License.
6 
+# You may obtain a copy of the License at
7 
+#
8 
+#     http://www.apache.org/licenses/LICENSE-2.0
9 
+#
10 
+# Unless required by applicable law or agreed to in writing, software
11 
+# distributed under the License is distributed on an "AS IS" BASIS,
12 
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 
+# See the License for the specific language governing permissions and
14 
+# limitations under the License.
15 
+
16 
+set -e
17 
+
18 
+CFG=/opt/redis/redis.conf
19 
+HOSTNAME=$(hostname)
20 
+DATADIR="/data"
21 
+# Port on which redis listens for connections.
22 
+PORT=6379
23 
+
24 
+# Ping everyone but ourself to see if there's a master. Only one pet starts at
25 
+# a time, so if we don't see a master we can assume the position is ours.
26 
+while read -ra LINE; do
27 
+    if [[ "${LINE}" == *"${HOSTNAME}"* ]]; then
28 
+        sed -i -e "s|^bind.*$|bind ${LINE}|" ${CFG}
29 
+    elif [ "$(/opt/redis/redis-cli -h $LINE info | grep role | sed 's,\r$,,')" = "role:master" ]; then
30 
+        # TODO: More restrictive regex?
31 
+        sed -i -e "s|^.*slaveof.*$|slaveof ${LINE} ${PORT}|" ${CFG}
32 
+    fi
33 
+done
34 
+
35 
+# Set the data directory for append only log and snapshot files. This should
36 
+# be a persistent volume for consistency.
37 
+sed -i -e "s|^.*dir .*$|dir ${DATADIR}|" ${CFG}
38 
+
39 
+# The append only log is written for every SET operation. Without this setting,
40 
+# redis just snapshots periodically which is only safe for a cache. This will
41 
+# produce an appendonly.aof file in the configured data dir.
42 
+sed -i -e "s|^appendonly .*$|appendonly yes|" ${CFG}
43 
+
44 
+# Every write triggers an fsync. Recommended default is "everysec", which
45 
+# is only safe for AP applications.
46 
+sed -i -e "s|^appendfsync .*$|appendfsync always|" ${CFG}
47 
+
48 
+
examples/pets/redis/redis.yaml
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0 
+# A headless service to create DNS records
1 
+apiVersion: v1
2 
+kind: Service
3 
+metadata:
4 
+  annotations:
5 
+    service.alpha.kubernetes.io/tolerate-unready-endpoints: "true"
6 
+  name: redis
7 
+  labels:
8 
+    app: redis
9 
+spec:
10 
+  ports:
11 
+  - port: 6379
12 
+    name: peer
13 
+  # *.redis.default.svc.cluster.local
14 
+  clusterIP: None
15 
+  selector:
16 
+    app: redis
17 
+---
18 
+apiVersion: apps/v1alpha1
19 
+kind: PetSet
20 
+metadata:
21 
+  name: rd
22 
+spec:
23 
+  serviceName: "redis"
24 
+  replicas: 3
25 
+  template:
26 
+    metadata:
27 
+      labels:
28 
+        app: redis
29 
+      annotations:
30 
+        pod.alpha.kubernetes.io/initialized: "true"
31 
+        pod.alpha.kubernetes.io/init-containers: '[
32 
+            {
33 
+                "name": "install",
34 
+                "image": "gcr.io/google_containers/redis-install:0.1",
35 
+                "imagePullPolicy": "Always",
36 
+                "args": ["--version=3.2.0", "--install-into=/opt", "--work-dir=/work-dir"],
37 
+                "volumeMounts": [
38 
+                    {
39 
+                        "name": "opt",
40 
+                        "mountPath": "/opt"
41 
+                    },
42 
+                    {
43 
+                        "name": "workdir",
44 
+                        "mountPath": "/work-dir"
45 
+                    }
46 
+                ]
47 
+            },
48 
+            {
49 
+                "name": "bootstrap",
50 
+                "image": "debian:jessie",
51 
+                "command": ["/work-dir/peer-finder"],
52 
+                "args": ["-on-start=\"/work-dir/on-start.sh\"", "-service=redis"],
53 
+                "env": [
54 
+                  {
55 
+                      "name": "POD_NAMESPACE",
56 
+                      "valueFrom": {
57 
+                          "fieldRef": {
58 
+                              "apiVersion": "v1",
59 
+                              "fieldPath": "metadata.namespace"
60 
+                          }
61 
+                      }
62 
+                   }
63 
+                ],
64 
+                "volumeMounts": [
65 
+                    {
66 
+                        "name": "opt",
67 
+                        "mountPath": "/opt"
68 
+                    },
69 
+                    {
70 
+                        "name": "workdir",
71 
+                        "mountPath": "/work-dir"
72 
+                    }
73 
+                ]
74 
+            }
75 
+        ]'
76 
+    spec:
77 
+      containers:
78 
+      - name: redis
79 
+        image: debian:jessie
80 
+        ports:
81 
+        - containerPort: 6379
82 
+          name: peer
83 
+        command:
84 
+        - /opt/redis/redis-server
85 
+        args:
86 
+        - /opt/redis/redis.conf
87 
+        readinessProbe:
88 
+          exec:
89 
+            command:
90 
+            - sh
91 
+            - -c
92 
+            - "/opt/redis/redis-cli -h $(hostname) ping"
93 
+          initialDelaySeconds: 15
94 
+          timeoutSeconds: 5
95 
+        volumeMounts:
96 
+        - name: datadir
97 
+          mountPath: /data
98 
+        - name: opt
99 
+          mountPath: /opt
100 
+      volumes:
101 
+      - name: opt
102 
+        emptyDir: {}
103 
+      - name: workdir
104 
+        emptyDir: {}
105 
+  volumeClaimTemplates:
106 
+  - metadata:
107 
+      name: datadir
108 
+      annotations:
109 
+        volume.alpha.kubernetes.io/storage-class: anything
110 
+    spec:
111 
+      accessModes: [ "ReadWriteOnce" ]
112 
+      resources:
113 
+        requests:
114 
+          storage: 20Gi
examples/pets/redis/test.sh
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0 
+#! /bin/bash
1 
+
2 
+# Copyright 2016 The Kubernetes Authors All rights reserved.
3 
+#
4 
+# Licensed under the Apache License, Version 2.0 (the "License");
5 
+# you may not use this file except in compliance with the License.
6 
+# You may obtain a copy of the License at
7 
+#
8 
+#     http://www.apache.org/licenses/LICENSE-2.0
9 
+#
10 
+# Unless required by applicable law or agreed to in writing, software
11 
+# distributed under the License is distributed on an "AS IS" BASIS,
12 
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 
+# See the License for the specific language governing permissions and
14 
+# limitations under the License.
15 
+
16 
+kubectl exec rd-0 -- /opt/redis/redis-cli -h rd-0.redis SET replicated:test true
17 
+kubectl exec rd-2 -- /opt/redis/redis-cli -h rd-2.redis GET replicated:test
18 
+
examples/pets/zookeeper/README.md
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0 
+# Zookeeper
1 
+
2 
+This example runs zookeeper through a petset.
3 
+
4 
+## Bootstrap
5 
+
6 
+Create the petset in this directory
7 
+```
8 
+$ kubetl create -f zookeeper.yaml
9 
+```
10 
+
11 
+Once you have all 3 nodes in Running, you can run the "test.sh" script in this directory.
12 
+
13 
+## Failover
14 
+
15 
+You can test failover by killing the leader. Insert a key:
16 
+```console
17 
+$ kubectl exec zoo-0 -- /opt/zookeeper/bin/zkCli.sh create /foo bar;
18 
+$ kubectl exec zoo-2 -- /opt/zookeeper/bin/zkCli.sh get /foo;
19 
+
20 
+Watch existing members:
21 
+```console
22 
+$ kubectl run --attach bbox --image=busybox --restart=Never -- sh -c 'while true; do for i in 0 1 2; do echo zoo-$i $(echo stats | nc zoo-$1.zk:2181 | grep Mode); sleep 1; done; done';
23 
+zoo-2 Mode: follower
24 
+zoo-0 Mode: follower
25 
+zoo-1 Mode: leader
26 
+zoo-2 Mode: follower
27 
+```
28 
+
29 
+Delete pets and wait for the petset controller to bring the back up:
30 
+```console
31 
+$ kubectl delete po -l app=zk
32 
+$ kubectl get po --watch-only
33 
+NAME      READY     STATUS     RESTARTS   AGE
34 
+zoo-0     0/1       Init:0/2   0          16s
35 
+zoo-0     0/1       Init:0/2   0         21s
36 
+zoo-0     0/1       PodInitializing   0         23s
37 
+zoo-0     1/1       Running   0         41s
38 
+zoo-1     0/1       Pending   0         0s
39 
+zoo-1     0/1       Init:0/2   0         0s
40 
+zoo-1     0/1       Init:0/2   0         14s
41 
+zoo-1     0/1       PodInitializing   0         17s
42 
+zoo-1     0/1       Running   0         18s
43 
+zoo-2     0/1       Pending   0         0s
44 
+zoo-2     0/1       Init:0/2   0         0s
45 
+zoo-2     0/1       Init:0/2   0         12s
46 
+zoo-2     0/1       Init:0/2   0         28s
47 
+zoo-2     0/1       PodInitializing   0         31s
48 
+zoo-2     0/1       Running   0         32s
49 
+...
50 
+
51 
+zoo-0 Mode: follower
52 
+zoo-1 Mode: leader
53 
+zoo-2 Mode: follower
54 
+```
55 
+
56 
+Check the previously inserted key:
57 
+```console
58 
+$ kubectl exec zoo-1 -- /opt/zookeeper/bin/zkCli.sh get /foo
59 
+ionid = 0x354887858e80035, negotiated timeout = 30000
60 
+
61 
+WATCHER::
62 
+
63 
+WatchedEvent state:SyncConnected type:None path:null
64 
+bar
65 
+```
66 
+
67 
+## Scaling
68 
+
69 
+You can scale up by modifying the number of replicas on the PetSet.
70 
+
71 
+## Image Upgrade
72 
+
73 
+TODO: Add details
74 
+
75 
+## Maintenance
76 
+
77 
+TODO: Add details
78 
+
79 
+## Limitations
80 
+* Both petset and init containers are in alpha
81 
+* Look through the on-start and on-change scripts for TODOs
82 
+* Doesn't support the addition of observers through the petset
83 
+* Only supports storage options that have backends for persistent volume claims
84 
+
examples/pets/zookeeper/init/Dockerfile
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+# Copyright 2016 The Kubernetes Authors All rights reserved.
1 
+#
2 
+# Licensed under the Apache License, Version 2.0 (the "License");
3 
+# you may not use this file except in compliance with the License.
4 
+# You may obtain a copy of the License at
5 
+#
6 
+#     http://www.apache.org/licenses/LICENSE-2.0
7 
+#
8 
+# Unless required by applicable law or agreed to in writing, software
9 
+# distributed under the License is distributed on an "AS IS" BASIS,
10 
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11 
+# See the License for the specific language governing permissions and
12 
+# limitations under the License.
13 
+
14 
+# TODO: get rid of bash dependency and switch to plain busybox.
15 
+# The tar in busybox also doesn't seem to understand compression.
16 
+FROM debian:jessie
17 
+MAINTAINER Prashanth.B <beeps@google.com>
18 
+
19 
+RUN apt-get update && apt-get install -y wget netcat
20 
+
21 
+ADD on-start.sh /
22 
+ADD on-change.sh /
23 
+# See contrib/pets/peer-finder for details
24 
+RUN wget -qO /peer-finder https://storage.googleapis.com/kubernetes-release/pets/peer-finder
25 
+
26 
+ADD install.sh /
27 
+RUN chmod -c 755 /install.sh /on-start.sh /on-change.sh /peer-finder
28 
+Entrypoint ["/install.sh"]
examples/pets/zookeeper/init/Makefile
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+# Copyright 2016 The Kubernetes Authors All rights reserved.
1 
+#
2 
+# Licensed under the Apache License, Version 2.0 (the "License");
3 
+# you may not use this file except in compliance with the License.
4 
+# You may obtain a copy of the License at
5 
+#
6 
+#     http://www.apache.org/licenses/LICENSE-2.0
7 
+#
8 
+# Unless required by applicable law or agreed to in writing, software
9 
+# distributed under the License is distributed on an "AS IS" BASIS,
10 
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11 
+# See the License for the specific language governing permissions and
12 
+# limitations under the License.
13 
+
14 
+all: push
15 
+
16 
+TAG = 0.1
17 
+PREFIX = gcr.io/google_containers/zookeeper-install
18 
+
19 
+container:
20 
+	docker build -t $(PREFIX):$(TAG) .
21 
+
22 
+push: container
23 
+	gcloud docker push $(PREFIX):$(TAG)
24 
+
25 
+clean:
26 
+	docker rmi $(PREFIX):$(TAG)
examples/pets/zookeeper/init/install.sh
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+#! /bin/bash
1 
+
2 
+# Copyright 2016 The Kubernetes Authors All rights reserved.
3 
+#
4 
+# Licensed under the Apache License, Version 2.0 (the "License");
5 
+# you may not use this file except in compliance with the License.
6 
+# You may obtain a copy of the License at
7 
+#
8 
+#     http://www.apache.org/licenses/LICENSE-2.0
9 
+#
10 
+# Unless required by applicable law or agreed to in writing, software
11 
+# distributed under the License is distributed on an "AS IS" BASIS,
12 
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 
+# See the License for the specific language governing permissions and
14 
+# limitations under the License.
15 
+
16 
+# This volume is assumed to exist and is shared with parent of the init
17 
+# container. It contains the zookeeper installation.
18 
+INSTALL_VOLUME="/opt"
19 
+
20 
+# This volume is assumed to exist and is shared with the peer-finder
21 
+# init container. It contains on-start/change configuration scripts.
22 
+WORKDIR_VOLUME="/work-dir"
23 
+
24 
+# As of April-2016 is 3.4.8 is the latest stable, but versions 3.5.0 onward
25 
+# allow dynamic reconfiguration.
26 
+VERSION="3.5.0-alpha"
27 
+
28 
+for i in "$@"
29 
+do
30 
+case $i in
31 
+    -v=*|--version=*)
32 
+    VERSION="${i#*=}"
33 
+    shift
34 
+    ;;
35 
+    -i=*|--install-into=*)
36 
+    INSTALL_VOLUME="${i#*=}"
37 
+    shift
38 
+    ;;
39 
+    -w=*|--work-dir=*)
40 
+    WORKDIR_VOLUME="${i#*=}"
41 
+    shift
42 
+    ;;
43 
+    *)
44 
+    # unknown option
45 
+    ;;
46 
+esac
47 
+done
48 
+
49 
+echo installing config scripts into "${WORKDIR_VOLUME}"
50 
+mkdir -p "${WORKDIR_VOLUME}"
51 
+cp /on-start.sh "${WORKDIR_VOLUME}"/
52 
+cp /on-change.sh "${WORKDIR_VOLUME}"/
53 
+cp /peer-finder "${WORKDIR_VOLUME}"/
54 
+
55 
+echo installing zookeeper-"${VERSION}" into "${INSTALL_VOLUME}"
56 
+mkdir -p "${INSTALL_VOLUME}"
57 
+wget -q -O - http://apache.mirrors.pair.com/zookeeper/zookeeper-"${VERSION}"/zookeeper-"${VERSION}".tar.gz | tar -xzf - -C "${INSTALL_VOLUME}"
58 
+mv "${INSTALL_VOLUME}"/zookeeper-"${VERSION}" "${INSTALL_VOLUME}"/zookeeper
59 
+cp "${INSTALL_VOLUME}"/zookeeper/conf/zoo_sample.cfg "${INSTALL_VOLUME}"/zookeeper/conf/zoo.cfg
60 
+
61 
+# TODO: Should dynamic config be tied to the version?
62 
+IFS="." read -ra RELEASE <<< "${VERSION}"
63 
+if [ $(expr "${RELEASE[1]}") -gt 4 ]; then
64 
+    echo zookeeper-"${VERSION}" supports dynamic reconfiguration, enabling it
65 
+    echo "standaloneEnabled=false" >> "${INSTALL_VOLUME}"/zookeeper/conf/zoo.cfg
66 
+    echo "dynamicConfigFile="${INSTALL_VOLUME}"/zookeeper/conf/zoo.cfg.dynamic" >> "${INSTALL_VOLUME}"/zookeeper/conf/zoo.cfg
67 
+fi
68 
+
69 
+# TODO: This is a hack, netcat is convenient to have in the zookeeper container
70 
+# I want to avoid using a custom zookeeper image just for this. So copy it.
71 
+NC=$(which nc)
72 
+if [ "${NC}" != "" ]; then
73 
+    echo copying nc into "${INSTALL_VOLUME}"
74 
+    cp "${NC}" "${INSTALL_VOLUME}"
75 
+fi
examples/pets/zookeeper/init/on-change.sh
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+#! /bin/bash
1 
+
2 
+# Copyright 2016 The Kubernetes Authors All rights reserved.
3 
+#
4 
+# Licensed under the Apache License, Version 2.0 (the "License");
5 
+# you may not use this file except in compliance with the License.
6 
+# You may obtain a copy of the License at
7 
+#
8 
+#     http://www.apache.org/licenses/LICENSE-2.0
9 
+#
10 
+# Unless required by applicable law or agreed to in writing, software
11 
+# distributed under the License is distributed on an "AS IS" BASIS,
12 
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 
+# See the License for the specific language governing permissions and
14 
+# limitations under the License.
15 
+
16 
+# This script configures zookeeper cluster member ship for version of zookeeper
17 
+# < 3.5.0. It should not be used with the on-start.sh script in this example.
18 
+# As of April-2016 is 3.4.8 is the latest stable.
19 
+
20 
+CFG=/opt/zookeeper/conf/zoo.cfg
21 
+CFG_BAK=/opt/zookeeper/conf/zoo.cfg.bak
22 
+MY_ID=/tmp/zookeeper/myid
23 
+
24 
+# write myid
25 
+IFS='-' read -ra ADDR <<< "$(hostname)"
26 
+echo $(expr "1" + "${ADDR[1]}") > "${MY_ID}"
27 
+
28 
+# TODO: This is a dumb way to reconfigure zookeeper because it allows dynamic
29 
+# reconfig, but it's simple.
30 
+i=0
31 
+echo "
32 
+tickTime=2000
33 
+initLimit=10
34 
+syncLimit=5
35 
+dataDir=/tmp/zookeeper
36 
+clientPort=2181
37 
+" > "${CFG_BAK}"
38 
+
39 
+while read -ra LINE; do
40 
+    let i=i+1
41 
+    echo "server.${i}=${LINE}:2888:3888" >> "${CFG_BAK}"
42 
+done
43 
+cp ${CFG_BAK} ${CFG}
44 
+
45 
+# TODO: Typically one needs to first add a new member as an "observer" then
46 
+# promote it to "participant", but that requirement is relaxed if we never
47 
+# start > 1 at a time.
48 
+/opt/zookeeper/bin/zkServer.sh restart
examples/pets/zookeeper/init/on-start.sh
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0 
+#! /bin/bash
1 
+
2 
+# Copyright 2016 The Kubernetes Authors All rights reserved.
3 
+#
4 
+# Licensed under the Apache License, Version 2.0 (the "License");
5 
+# you may not use this file except in compliance with the License.
6 
+# You may obtain a copy of the License at
7 
+#
8 
+#     http://www.apache.org/licenses/LICENSE-2.0
9 
+#
10 
+# Unless required by applicable law or agreed to in writing, software
11 
+# distributed under the License is distributed on an "AS IS" BASIS,
12 
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 
+# See the License for the specific language governing permissions and
14 
+# limitations under the License.
15 
+
16 
+# This script configures zookeeper cluster member ship for version of zookeeper
17 
+# >= 3.5.0. It should not be used with the on-change.sh script in this example.
18 
+# As of April-2016 is 3.4.8 is the latest stable.
19 
+
20 
+# Both /opt and /tmp/zookeeper are assumed to be volumes shared with the parent.
21 
+CFG=/opt/zookeeper/conf/zoo.cfg.dynamic
22 
+CFG_BAK=/opt/zookeeper/conf/zoo.cfg.bak
23 
+MY_ID_FILE=/tmp/zookeeper/myid
24 
+HOSTNAME=$(hostname)
25 
+
26 
+while read -ra LINE; do
27 
+    PEERS=("${PEERS[@]}" $LINE)
28 
+done
29 
+
30 
+# Don't add the first member as an observer
31 
+if [ ${#PEERS[@]} -eq 1 ]; then
32 
+    # We need to write our index in this list of servers into MY_ID_FILE.
33 
+    # Note that this may not always coincide with the hostname id.
34 
+    echo 1 > "${MY_ID_FILE}"
35 
+    echo "server.1=${PEERS[0]}:2888:3888;2181" > "${CFG}"
36 
+    # TODO: zkServer-initialize is the safe way to handle changes to datadir
37 
+    # because simply starting will create a new datadir, BUT if the user changed
38 
+    # pod template they might end up with 2 datadirs and brief split brain.
39 
+    exit
40 
+fi
41 
+
42 
+# Every subsequent member is added as an observer and promoted to a participant
43 
+echo "" > "${CFG_BAK}"
44 
+i=0
45 
+for peer in "${PEERS[@]}"; do
46 
+    let i=i+1
47 
+    if [[ "${peer}" == *"${HOSTNAME}"* ]]; then
48 
+      MY_ID=$i
49 
+      MY_NAME=${peer}
50 
+      echo $i > "${MY_ID_FILE}"
51 
+      echo "server.${i}=${peer}:2888:3888:observer;2181" >> "${CFG_BAK}"
52 
+    else
53 
+      echo "server.${i}=${peer}:2888:3888:participant;2181" >> "${CFG_BAK}"
54 
+    fi
55 
+done
56 
+
57 
+# Once the dynamic config file is written it shouldn't be modified, so the final
58 
+# reconfigure needs to happen through the "reconfig" command.
59 
+cp ${CFG_BAK} ${CFG}
60 
+
61 
+# TODO: zkServer-initialize is the safe way to handle changes to datadir
62 
+# because simply starting will create a new datadir, BUT if the user changed
63 
+# pod template they might end up with 2 datadirs and brief split brain.
64 
+/opt/zookeeper/bin/zkServer.sh start
65 
+
66 
+# TODO: We shouldn't need to specify the address of the master as long as
67 
+# there's quorum. According to the docs the new server is just not allowed to
68 
+# vote, it's still allowed to propose config changes, and it knows the
69 
+# existing members of the ensemble from *its* config. This works as expected,
70 
+# but we should correlate with more satisfying empirical evidence.
71 
+/opt/zookeeper/bin/zkCli.sh reconfig -add "server.$MY_ID=$MY_NAME:2888:3888:participant;2181"
72 
+/opt/zookeeper/bin/zkServer.sh stop
examples/pets/zookeeper/test.sh
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0 
+#! /bin/bash
1 
+
2 
+# Copyright 2016 The Kubernetes Authors All rights reserved.
3 
+#
4 
+# Licensed under the Apache License, Version 2.0 (the "License");
5 
+# you may not use this file except in compliance with the License.
6 
+# You may obtain a copy of the License at
7 
+#
8 
+#     http://www.apache.org/licenses/LICENSE-2.0
9 
+#
10 
+# Unless required by applicable law or agreed to in writing, software
11 
+# distributed under the License is distributed on an "AS IS" BASIS,
12 
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 
+# See the License for the specific language governing permissions and
14 
+# limitations under the License.
15 
+
16 
+kubectl exec zoo-0 -- /opt/zookeeper/bin/zkCli.sh create /foo bar;
17 
+kubectl exec zoo-2 -- /opt/zookeeper/bin/zkCli.sh get /foo;
18 
+
examples/pets/zookeeper/zookeeper.yaml
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0 
+# A headless service to create DNS records
1 
+apiVersion: v1
2 
+kind: Service
3 
+metadata:
4 
+  annotations:
5 
+    service.alpha.kubernetes.io/tolerate-unready-endpoints: "true"
6 
+  name: zk
7 
+  labels:
8 
+    app: zk
9 
+spec:
10 
+  ports:
11 
+  - port: 2888
12 
+    name: peer
13 
+  - port: 3888
14 
+    name: leader-election
15 
+  # *.zk.default.svc.cluster.local
16 
+  clusterIP: None
17 
+  selector:
18 
+    app: zk
19 
+---
20 
+apiVersion: apps/v1alpha1
21 
+kind: PetSet
22 
+metadata:
23 
+  name: zoo
24 
+spec:
25 
+  serviceName: "zk"
26 
+  replicas: 3
27 
+  template:
28 
+    metadata:
29 
+      labels:
30 
+        app: zk
31 
+      annotations:
32 
+        pod.alpha.kubernetes.io/initialized: "true"
33 
+        pod.alpha.kubernetes.io/init-containers: '[
34 
+            {
35 
+                "name": "install",
36 
+                "image": "gcr.io/google_containers/zookeeper-install:0.1",
37 
+                "imagePullPolicy": "Always",
38 
+                "args": ["--version=3.5.0-alpha", "--install-into=/opt", "--work-dir=/work-dir"],
39 
+                "volumeMounts": [
40 
+                    {
41 
+                        "name": "opt",
42 
+                        "mountPath": "/opt/"
43 
+                    },
44 
+                    {
45 
+                        "name": "workdir",
46 
+                        "mountPath": "/work-dir"
47 
+                    }
48 
+                ]
49 
+            },
50 
+            {
51 
+                "name": "bootstrap",
52 
+                "image": "java:openjdk-8-jre",
53 
+                "command": ["/work-dir/peer-finder"],
54 
+                "args": ["-on-start=\"/work-dir/on-start.sh\"", "-service=zk"],
55 
+                "env": [
56 
+                  {
57 
+                      "name": "POD_NAMESPACE",
58 
+                      "valueFrom": {
59 
+                          "fieldRef": {
60 
+                              "apiVersion": "v1",
61 
+                              "fieldPath": "metadata.namespace"
62 
+                          }
63 
+                      }
64 
+                   }
65 
+                ],
66 
+                "volumeMounts": [
67 
+                    {
68 
+                        "name": "opt",
69 
+                        "mountPath": "/opt/"
70 
+                    },
71 
+                    {
72 
+                        "name": "workdir",
73 
+                        "mountPath": "/work-dir"
74 
+                    },
75 
+                    {
76 
+                        "name": "datadir",
77 
+                        "mountPath": "/tmp/zookeeper"
78 
+                    }
79 
+                ]
80 
+            }
81 
+        ]'
82 
+    spec:
83 
+      containers:
84 
+      - name: zk
85 
+        image: java:openjdk-8-jre
86 
+        ports:
87 
+        - containerPort: 2888
88 
+          name: peer
89 
+        - containerPort: 3888
90 
+          name: leader-election
91 
+        command:
92 
+        - /opt/zookeeper/bin/zkServer.sh
93 
+        args:
94 
+        - start-foreground
95 
+        readinessProbe:
96 
+          exec:
97 
+            command:
98 
+            - sh
99 
+            - -c
100 
+            - "/opt/zookeeper/bin/zkCli.sh ls /"
101 
+          initialDelaySeconds: 15
102 
+          timeoutSeconds: 5
103 
+        volumeMounts:
104 
+        - name: datadir
105 
+          mountPath: /tmp/zookeeper
106 
+        - name: opt
107 
+          mountPath: /opt/
108 
+      volumes:
109 
+      - name: opt
110 
+        emptyDir: {}
111 
+      - name: workdir
112 
+        emptyDir: {}
113 
+  volumeClaimTemplates:
114 
+  - metadata:
115 
+      name: datadir
116 
+      annotations:
117 
+        volume.alpha.kubernetes.io/storage-class: anything
118 
+    spec:
119 
+      accessModes: [ "ReadWriteOnce" ]
120 
+      resources:
121 
+        requests:
122 
+          storage: 20Gi