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vendor/github.com/hyperhq/hypercli/docs/admin/systemd.md

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+<!--[metadata]>
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+aliases = ["/engine/reference/logging/systemd/"]
+title = "Control and configure Docker with systemd"
+description = "Controlling and configuring Docker using systemd"
+keywords = ["docker, daemon, systemd,  configuration"]
+[menu.main]
+parent = "engine_admin"
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+<![end-metadata]-->
+
+# Control and configure Docker with systemd
+
+Many Linux distributions use systemd to start the Docker daemon. This document
+shows a few examples of how to customize 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.
+
+The recommended way is to use a systemd drop-in file. These are local files in
+the `/etc/systemd/system/docker.service.d` directory. This could also be
+`/etc/systemd/system/docker.service`, which also works for overriding the
+defaults from `/lib/systemd/system/docker.service`.
+
+However, if you had previously used a package which had an `EnvironmentFile`
+(often pointing to `/etc/sysconfig/docker`) then for backwards compatibility,
+you drop a file in the `/etc/systemd/system/docker.service.d`
+directory including the following:
+
+    [Service]
+    EnvironmentFile=-/etc/sysconfig/docker
+    EnvironmentFile=-/etc/sysconfig/docker-storage
+    EnvironmentFile=-/etc/sysconfig/docker-network
+    ExecStart=
+    ExecStart=/usr/bin/docker daemon -H fd:// $OPTIONS \
+              $DOCKER_STORAGE_OPTIONS \
+              $DOCKER_NETWORK_OPTIONS \
+              $BLOCK_REGISTRY \
+              $INSECURE_REGISTRY
+
+To check if the `docker.service` uses an `EnvironmentFile`:
+
+    $ sudo systemctl show docker | grep EnvironmentFile
+    EnvironmentFile=-/etc/sysconfig/docker (ignore_errors=yes)
+
+Alternatively, find out where the service file is located:
+
+    $ sudo systemctl status docker | grep Loaded
+       Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled)
+    $ sudo grep EnvironmentFile /usr/lib/systemd/system/docker.service
+    EnvironmentFile=-/etc/sysconfig/docker
+
+You can customize the Docker daemon options using override files as explained in the
+[HTTP Proxy example](#http-proxy) below. The files located in `/usr/lib/systemd/system`
+or `/lib/systemd/system` contain the default options and should not be edited.
+
+### 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.service` file looks something like:
+
+    [Unit]
+    Description=Docker Application Container Engine
+    Documentation=https://docs.docker.com
+    After=network.target docker.socket
+    Requires=docker.socket
+
+    [Service]
+    Type=notify
+    ExecStart=/usr/bin/docker daemon -H fd://
+    LimitNOFILE=1048576
+    LimitNPROC=1048576
+    TasksMax=1048576
+
+    [Install]
+    Also=docker.socket
+
+This will allow us to add extra flags via a drop-in file (mentioned above) by
+placing a file containing the following in the `/etc/systemd/system/docker.service.d`
+directory:
+
+    [Service]
+    ExecStart=
+    ExecStart=/usr/bin/docker daemon -H fd:// --graph="/mnt/docker-data" --storage-driver=overlay
+
+You can also set other environment variables in this file, for example, the
+`HTTP_PROXY` environment variables described below.
+
+To modify the ExecStart configuration, specify an empty configuration followed
+by a new configuration as follows:
+
+    [Service]
+    ExecStart=
+    ExecStart=/usr/bin/docker daemon -H fd:// --bip=172.17.42.1/16
+
+If you fail to specify an empty configuration, Docker reports an error such as:
+
+    docker.service has more than one ExecStart= setting, which is only allowed for Type=oneshot services. Refusing.
+
+### 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.
+
+First, create a systemd drop-in directory for the docker service:
+
+    mkdir /etc/systemd/system/docker.service.d
+
+Now create a file called `/etc/systemd/system/docker.service.d/http-proxy.conf`
+that adds the `HTTP_PROXY` environment variable:
+
+    [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,127.0.0.1,docker-registry.somecorporation.com"
+
+Flush changes:
+
+    $ sudo systemctl daemon-reload
+
+Verify that the configuration has been loaded:
+
+    $ sudo systemctl show docker --property Environment
+    Environment=HTTP_PROXY=http://proxy.example.com:80/
+
+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`.