@@ -33,17 +33,33 @@ If you want Docker to start at boot, you should also:

 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.

+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`.

-Check if the `docker.service` uses an `EnvironmentFile`:

+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 -d -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, and look for the

-property:

+Alternatively, find out where the service file is located:

     $ sudo systemctl status docker | grep Loaded

        Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled)

@@ -69,18 +85,20 @@ In this example, we'll assume that your `docker.service` file looks something li

     [Service]

     Type=notify

-    EnvironmentFile=-/etc/sysconfig/docker

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

+    ExecStart=/usr/bin/docker daemon -H fd://

     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`:

+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:

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

+    [Service]

+    ExecStart=

+    ExecStart=/usr/bin/docker daemon -H fd:// --graph /mnt/docker-data --storage-driver btrfs

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

 `HTTP_PROXY` environment variables described below.