Docker role

This role will install Docker on a target machine running Debian or Ubuntu.

• Docker role
  • Variable reference
    • Optional variables
  • Example
    • Select the Docker version
    • Select the Docker-compose version
  • Informations
    • Important about the network
    • Update of docker-compose

Variable reference

Optional variables

Variable	Description	Default value
docker_compose	install docker-compose	true
docker_user	name of the user who is going to use docker	root
docker_rootless	run the Docker daemon as a non-root user (Rootless mode)	false
docker_pinned	see section Select the Docker version bellow	None
docker_compose_version	see section Select the Docker-compose version bellow	None
docker_registry_login	see bellow	None

docker_registry_login is used when you need to define an url/username/password to access specific dockers registries.

The object is defined like this:

docker_registry_login:
  - url: "docker.cosium.dev"
    username: "user"
    password: "pass"
  - url: "something"
    username: "user"
    password: "pass"

Example

Select the Docker version

By default, the latest version of Docker will be installed, but you can specify a version by setting this variable:

docker_pinned: "17.09.0~ce-0~debian"
# Or only pin the major version {#or-only-pin-the-major-version}
docker_pinned: "27*"

To find out the list of available versions, use this command on the target server:

# apt-cache madison docker-ce {#apt-cache-madison-docker-ce}
 docker-ce | 17.09.0~ce-0~debian | https://download.docker.com/linux/debian stretch/stable amd64 Packages
 docker-ce | 17.06.2~ce-0~debian | https://download.docker.com/linux/debian stretch/stable amd64 Packages
 docker-ce | 17.06.1~ce-0~debian | https://download.docker.com/linux/debian stretch/stable amd64 Packages
 docker-ce | 17.06.0~ce-0~debian | https://download.docker.com/linux/debian stretch/stable amd64 Packages
 docker-ce | 17.03.2~ce-0~debian-stretch | https://download.docker.com/linux/debian stretch/stable amd64 Packages
 docker-ce | 17.03.1~ce-0~debian-stretch | https://download.docker.com/linux/debian stretch/stable amd64 Packages
 docker-ce | 17.03.0~ce-0~debian-stretch | https://download.docker.com/linux/debian stretch/stable amd64 Packages

Select the Docker-compose version

By default, this role will install the latest version of docker-compose. You can also select a specific docker-compose version by setting this variable:

docker_compose_version: "1.17.1"

You can find the list of docker-compose release here: https://github.com/docker/compose/releases/

Informations

Important about the network

This role let docker create the docker0 bridge interface. This means that if docker sees a route for all the rfc1918 networks (10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16), it will fail.

This basically is the case for the machines in the DMZ: all those routes are defined so that the default gateway can be the BGP router, typically you have such configuration for their DMZ interface:

# DMZ6 {#dmz6}
auto eth136
       iface eth136 inet static
       address 10.12.36.96
       netmask 24
       dns-nameservers 10.12.1.207 10.12.1.2
       dns-search cosium.com


# static route {#static-route}
up route add -net 10.0.0.0 netmask 255.0.0.0 gw 10.12.36.254 dev eth136
up route add -net 172.16.0.0 netmask 255.240.0.0 gw 10.12.36.254 dev eth136
up route add -net 192.168.0.0 netmask 255.255.0.0 gw 10.12.36.254 dev eth136

To allow doker to create the docker0 interface, you basically have to remove the last line. Currently we don't use any 192.168.0.0/16 network so it won't be an issue.

Update of docker-compose

To perform an update, add this parameter: --extra-vars "docker_compose_update_now=true" , true is case-sensitive since it's evaluated as a string in this case.

This role will also update if this parameter is present: --extra-vars "global_update_now=true" , true is also case-sensitive since it's evaluated as a string in this case.

The update will be skipped if you already have the latest version of the binary.