To install docker on a host you have to put it into that group in inventory now, instead of adding the role to each host playbook. Idea is to extend the group docker_host playbook by more docker related things as for example metrics and monitoring.
yamllint warned: host_vars/hobbes.n39.eu/vars.yml 1:1 warning missing document start "---" (document-start) host_vars/krypton.n39.eu/vars.yml 1:1 warning missing document start "---" (document-start) host_vars/localhost/vars.yml 1:1 warning missing document start "---" (document-start) host_vars/platon.n39.eu/vars.yml 1:1 warning missing document start "---" (document-start) host_vars/pottwal.n39.eu/vars.yml 1:1 warning missing document start "---" (document-start) host_vars/radon.n39.eu/vars.yml 1:1 warning missing document start "---" (document-start) host_vars/tau.netz39.de/vars.yml 1:1 warning missing document start "---" (document-start) host_vars/unicorn.n39.eu/vars.yml 1:1 warning missing document start "---" (document-start)
