From db4779476ec5deaabb6431589e74e70b19a17797 Mon Sep 17 00:00:00 2001 From: David M Noriega Date: Fri, 29 Sep 2017 14:06:30 -0700 Subject: [PATCH] docs are good :) --- README.md | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/README.md b/README.md index efe0421..610e5cb 100644 --- a/README.md +++ b/README.md @@ -36,6 +36,29 @@ Docker Compose installation options. (Used only for RedHat/CentOS.) You can enable the Edge or Test repo by setting the respective vars to `1`. +### devicemapper + +Out of the box this role deploys docker with the overlay driver, but the only +officially supported configuration of Docker on RedHat/CentOS is to use device +mapper as the storage driver (Not to be confused with `docker volume`). Docker +can configure the lvm thin provisioning when provided a raw block device (such +as a second disk). To deploy this configuration, set the following variables in +your deploy: + + docker_devicemapper_raw_device: /dev/sdb # Or /dev/vdb or ... + docker_configure_daemon: true + +For more information, see the [device mapper driver][devicemapper] documentation. + +### Docker daemon configuration + +To configure devicemapper as the storage driver, this role has to configure the +docker daemon via `daemon.json`, but you can also use this to configure the +daemon as you wish by overriding `docker_daemon_config`. This yaml hash is then +converted to json. Making changes to `daemon.json` then require a restart of the +service, but this role does not default to restarting the service. To trigger a +restart when reconfiguring the daemon, set `docker_restart` to `true`. + ## Use with Ansible (and `docker` Python library) Many users of this role wish to also use Ansible to then _build_ Docker images and manage Docker containers on the server where Docker is installed. In this case, you can easily add in the `docker` Python library using the `geerlingguy.pip` role: @@ -71,3 +94,5 @@ MIT / BSD ## Author Information This role was created in 2017 by [Jeff Geerling](https://www.jeffgeerling.com/), author of [Ansible for DevOps](https://www.ansiblefordevops.com/). + +[devicemapper]: https://docs.docker.com/engine/userguide/storagedriver/device-mapper-driver/