@@ -98,6 +98,7 @@ pages:

 - ['articles/ambassador_pattern_linking.md', 'Articles', 'Cross-Host linking using ambassador containers']

 - ['articles/runmetrics.md', 'Articles', 'Runtime metrics']

 - ['articles/b2d_volume_resize.md', 'Articles', 'Increasing a Boot2Docker volume']

+- ['articles/systemd.md', 'Articles', 'Controlling and configuring Docker using Systemd']

 # Reference

 - ['reference/index.md', '**HIDDEN**']

new file mode 100644

@@ -0,0 +1,101 @@

+page_title: Controlling and configuring Docker using Systemd

+page_description: Controlling and configuring Docker using Systemd

+page_keywords: docker, daemon, systemd, configuration

+

+# Controlling and configuring Docker using Systemd

+

+Many Linux distributions use systemd to start the Docker daemon. This document

+shows a few examples of how to customise Docker's settings.

+

+## Starting the Docker daemon

+

+Once Docker is installed, you will need to start the Docker daemon.

+

+    $ sudo systemctl start docker

+    # or on older distributions, you may need to use

+    $ sudo service docker start

+

+If you want Docker to start at boot, you should also:

+

+    $ sudo systemctl enable docker

+    # or on older distributions, you may need to use

+    $ sudo chkconfig docker on

+

+## Custom Docker daemon options

+

+There are a number of ways to configure the daemon flags and environment variables

+for your Docker daemon. 

+

+If the `docker.service` file is set to use an `EnvironmentFile`

+(often pointing to `/etc/sysconfig/docker`) then you can modify the

+referenced file.

+

+Or, you may need to edit the `docker.service` file, which can be in `/usr/lib/systemd/system`

+or `/etc/systemd/service`.

+

+### Runtime directory and storage driver

+

+You may want to control the disk space used for Docker images, containers

+and volumes by moving it to a separate partition.

+

+In this example, we'll assume that your `docker.services` file looks something like:

+

+    [Unit]

+    Description=Docker Application Container Engine

+    Documentation=http://docs.docker.com

+    After=network.target docker.socket

+    Requires=docker.socket

+    

+    [Service]

+    Type=notify

+    EnvironmentFile=-/etc/sysconfig/docker

+    ExecStart=/usr/bin/docker -d -H fd:// $OPTIONS

+    LimitNOFILE=1048576

+    LimitNPROC=1048576

+    

+    [Install]

+    Also=docker.socket

+

+This will allow us to add extra flags to the `/etc/sysconfig/docker` file by

+setting `OPTIONS`:

+

+    OPTIONS="--graph /mnt/docker-data --storage btrfs"

+

+You can also set other environment variables in this file, for example, the

+`HTTP_PROXY` environment variables described below.

+

+### HTTP Proxy

+

+This example overrides the default `docker.service` file.

+

+If you are behind a HTTP proxy server, for example in corporate settings, 

+you will need to add this configuration in the Docker systemd service file.

+

+Copy file `/usr/lib/systemd/system/docker.service` to `/etc/systemd/system/docker/service`.

+

+Add the following to the `[Service]` section in the new file:

+

+    Environment="HTTP_PROXY=http://proxy.example.com:80/"

+

+If you have internal Docker registries that you need to contact without

+proxying you can specify them via the `NO_PROXY` environment variable:

+

+    Environment="HTTP_PROXY=http://proxy.example.com:80/" "NO_PROXY=localhost,127.0.0.0/8,docker-registry.somecorporation.com"

+

+Flush changes:

+

+    $ sudo systemctl daemon-reload

+    

+Restart Docker:

+

+    $ sudo systemctl restart docker

+

+## Manually creating the systemd unit files

+

+When installing the binary without a package, you may want

+to integrate Docker with systemd. For this, simply install the two unit files

+(service and socket) from [the github

+repository](https://github.com/docker/docker/tree/master/contrib/init/systemd)

+to `/etc/systemd/system`.

+

+

@@ -53,3 +53,9 @@ service:

 To start on system boot:

     $ sudo systemctl enable docker

+

+## Custom daemon options

+

+If you need to add an HTTP Proxy, set a different directory or partition for the

+Docker runtime files, or make other customizations, read our systemd article to

+learn how to [customize your systemd Docker daemon options](/articles/systemd/).

@@ -45,11 +45,11 @@ to `/etc/systemd/system`.

 CentOS-7 introduced firewalld, which is a wrapper around iptables and can

 conflict with Docker.

-When firewalld is started or restarted it will remove the `DOCKER` chain

+When `firewalld` is started or restarted it will remove the `DOCKER` chain

 from iptables, preventing Docker from working properly.

-When using systemd, firewalld is started before Docker, but if you

-start or restart firewalld  after Docker, you will have to restart the Docker daemon.

+When using systemd, `firewalld` is started before Docker, but if you

+start or restart `firewalld` after Docker, you will have to restart the Docker daemon.

 ## Installing Docker - CentOS-6

 Please note that this for CentOS-6, this package is part of [Extra Packages

@@ -103,7 +103,13 @@ Run a simple bash shell to test the image:

     $ sudo docker run -i -t centos /bin/bash

 If everything is working properly, you'll get a simple bash prompt. Type

-exit to continue.

+`exit` to continue.

+

+## Custom daemon options

+

+If you need to add an HTTP Proxy, set a different directory or partition for the

+Docker runtime files, or make other customizations, read our systemd article to

+learn how to [customize your systemd Docker daemon options](/articles/systemd/).

 ## Dockerfiles

 The CentOS Project provides a number of sample Dockerfiles which you may use

@@ -67,28 +67,11 @@ member of that group in order to contact the `docker -d` process.

 Adding users to the `docker` group is *not* necessary for Docker versions 1.0

 and above.

-## HTTP Proxy

+## Custom daemon options

-If you are behind a HTTP proxy server, for example in corporate settings, 

-you will need to add this configuration in the Docker *systemd service file*.

-

-Edit file `/usr/lib/systemd/system/docker.service`. Add the following to

-section `[Service]` :

-

-    Environment="HTTP_PROXY=http://proxy.example.com:80/"

-

-If you have internal Docker registries that you need to contact without

-proxying you can specify them via the `NO_PROXY` environment variable:

-

-    Environment="HTTP_PROXY=http://proxy.example.com:80/" "NO_PROXY=localhost,127.0.0.0/8,docker-registry.somecorporation.com"

-

-Flush changes:

-

-    $ systemctl daemon-reload

-    

-Restart Docker:

-

-    $ systemctl start docker

+If you need to add an HTTP Proxy, set a different directory or partition for the

+Docker runtime files, or make other customizations, read our systemd article to

+learn how to [customize your systemd Docker daemon options](/articles/systemd/).

 ## What next?

@@ -42,3 +42,9 @@ service:

 To start on system boot:

     $ sudo systemctl enable lxc-docker

+

+## Custom daemon options

+

+If you need to add an HTTP Proxy, set a different directory or partition for the

+Docker runtime files, or make other customizations, read our systemd article to

+learn how to [customize your systemd Docker daemon options](/articles/systemd/).

@@ -91,3 +91,7 @@ To start the `docker` daemon:

 To start on system boot:

     $ sudo systemctl enable docker

+   

+If you need to add an HTTP Proxy, set a different directory or partition for the

+Docker runtime files, or make other customizations, read our systemd article to

+learn how to [customize your systemd Docker daemon options](/articles/systemd/).

@@ -71,5 +71,13 @@ hand to ensure the `FW_ROUTE` flag is set to `yes` like so:

 **Done!**

+## Custom daemon options

+

+If you need to add an HTTP Proxy, set a different directory or partition for the

+Docker runtime files, or make other customizations, read our systemd article to

+learn how to [customize your systemd Docker daemon options](/articles/systemd/).

+

+## What's next

+

 Continue with the [User Guide](/userguide/).

@@ -75,6 +75,12 @@ and set `enabled=1` in the `[ol6_addons]` or the `[ol7_addons]` stanza.

 **Done!**

+## Custom daemon options

+

+If you need to add an HTTP Proxy, set a different directory or partition for the

+Docker runtime files, or make other customizations, read our systemd article to

+learn how to [customize your systemd Docker daemon options](/articles/systemd/).

+

 ## Using the btrfs storage engine

 Docker on Oracle Linux 6 and 7 supports the use of the btrfs storage engine.

@@ -83,6 +83,13 @@ Now let's verify that Docker is working.

 Continue with the [User Guide](/userguide/).

+## Custom daemon options

+

+If you need to add an HTTP Proxy, set a different directory or partition for the

+Docker runtime files, or make other customizations, read our systemd article to

+learn how to [customize your systemd Docker daemon options](/articles/systemd/).

+

+

 ## Issues?

 If you have any issues - please report them directly in the