Running Kubernetes on Photon ----------------------------------------------------- (Note: Modified Getting started Kubernetes docs accordingly to run Kubernetes on Photon) **Table of Contents** - [Prerequisites](#prerequisites) - [Instructions](#instructions) ## Prerequisites 1. You need 2 or more machines with Photon installed. ## Instructions This is a getting started guide for Photon. It is a manual configuration so you understand all the underlying packages / services / ports, etc... This guide will only get ONE node (previously minion) working. The Kubernetes package provides a few services: kube-apiserver, kube-scheduler, kube-controller-manager, kubelet, kube-proxy. These services are managed by systemd and the configuration resides in a central location: /etc/kubernetes. We will break the services up between the hosts. The first host, photon-master, will be the Kubernetes master. This host will run the kube-apiserver, kube-controller-manager, and kube-scheduler. In addition, the master will also run _etcd_ (not needed if _etcd_ runs on a different host but this guide assumes that _etcd_ and Kubernetes master run on the same host). The remaining host, photon-node will be the node and run kubelet, proxy and docker. **System Information:** Hosts: ``` photon-master = 192.168.121.9 photon-node = 192.168.121.65 ``` **Prepare the hosts:** * Install Kubernetes on all hosts - photon-{master,node}. ```sh tdnf install kubernetes ``` * Install etcd and iptables on photon-master ```sh tdnf install etcd iptables ``` * Install docker on photon-node ```sh tdnf install docker ``` * Add master and node to /etc/hosts on all machines (not needed if hostnames already in DNS). Make sure that communication works between photon-master and photon-node by using a utility such as ping. ```sh echo "192.168.121.9 photon-master 192.168.121.65 photon-node" >> /etc/hosts ``` * Edit /etc/kubernetes/config which will be the same on all hosts (master and node) to contain: ```sh # Comma separated list of nodes in the etcd cluster KUBE_MASTER="--master=http://photon-master:8080" # logging to stderr means we get it in the systemd journal KUBE_LOGTOSTDERR="--logtostderr=true" # journal message level, 0 is debug KUBE_LOG_LEVEL="--v=0" # Should this cluster be allowed to run privileged docker containers KUBE_ALLOW_PRIV="--allow_privileged=false" ``` **Configure the Kubernetes services on the master.** * Edit /etc/kubernetes/apiserver to appear as such. The service_cluster_ip_range IP addresses must be an unused block of addresses, not used anywhere else. They do not need to be routed or assigned to anything. ```sh # The address on the local server to listen to. KUBE_API_ADDRESS="--address=0.0.0.0" # Comma separated list of nodes in the etcd cluster KUBE_ETCD_SERVERS="--etcd_servers=http://127.0.0.1:4001" # Address range to use for services KUBE_SERVICE_ADDRESSES="--service-cluster-ip-range=10.254.0.0/16" # Add your own! KUBE_API_ARGS="" ``` * Start the appropriate services on master: ```sh for SERVICES in etcd kube-apiserver kube-controller-manager kube-scheduler; do systemctl restart $SERVICES systemctl enable $SERVICES systemctl status $SERVICES done ``` * Addition of nodes: * Create following node.json file on Kubernetes master node: ```json { "apiVersion": "v1", "kind": "Node", "metadata": { "name": "photon-node", "labels":{ "name": "photon-node-label"} }, "spec": { "externalID": "photon-node" } } ``` Now create a node object internally in your Kubernetes cluster by running: ```console $ kubectl create -f ./node.json $ kubectl get nodes NAME LABELS STATUS photon-node name=photon-node-label Unknown ``` Please note that in the above, it only creates a representation for the node _photon-node_ internally. It does not provision the actual _photon-node_. Also, it is assumed that _photon-node_ (as specified in `name`) can be resolved and is reachable from Kubernetes master node. This guide will discuss how to provision a Kubernetes node (photon-node) below. **Configure the Kubernetes services on the node.** ***We need to configure the kubelet on the node.*** * Edit /etc/kubernetes/kubelet to appear as such: ```sh ### # Kubernetes kubelet (node) config # The address for the info server to serve on (set to 0.0.0.0 or "" for all interfaces) KUBELET_ADDRESS="--address=0.0.0.0" # You may leave this blank to use the actual hostname KUBELET_HOSTNAME="--hostname_override=photon-node" # location of the api-server KUBELET_API_SERVER="--api_servers=http://photon-master:8080" # Add your own! #KUBELET_ARGS="" ``` * Start the appropriate services on the node (photon-node). ```sh for SERVICES in kube-proxy kubelet docker; do systemctl restart $SERVICES systemctl enable $SERVICES systemctl status $SERVICES done ``` * Check to make sure now the cluster can see the photon-node on photon-master, and its status changes to _Ready_. ```console kubectl get nodes NAME LABELS STATUS photon-node name=photon-node-label Ready ``` * Deletion of nodes: To delete _photon-node_ from your Kubernetes cluster, one should run the following on photon-master (Please do not do it, it is just for information): ```sh kubectl delete -f ./node.json ``` *You should be finished!* **The cluster should be running! Launch a test pod.** You should have a functional cluster, check out [101](https://github.com/GoogleCloudPlatform/kubernetes/blob/master/docs/user-guide/walkthrough/README.md)!