Ansible Role SSH Cluster

This is an ansible role for installing SSH keys between Hosts. This might be useful for rsync over SSH or other tools.

Usage

Example usage:

- hosts: webservers
  vars:
    ssh_targets: "{{ groups['webservers'] }}"
  roles:
    - role: ccremer.ssh-cluster

This will enable root access between all hosts in group webservers. e.g. Server A can access Server B and C over SSH. Server B can access Server A and C, and so on. SSH keys will be generated if they don't exist yet and inserted into ~/.ssh/authorized_keys on the target machines. Also, the current host keys of the target machines will get added to ~/.ssh/known_hosts, so that you do not need to confirm first connection, while still having host key checks enabled.

Advanced Usage

Advanced usage (with default values):

- hosts: server.a.localdomain
  vars:
    # This definition basically says that server A can access server B and C, but B and C cannot access A.
    # The actual default is empty list []
    ssh_targets:
      - server-b.localdomain
      - server-c.localdomain
    # Setting the user is theoretically implemented, but UNTESTED (I needed root access)
    ssh_user: root
    ssh_known_hosts_rehash: true
  roles:
    - role: ccremer.ssh-cluster

Gotchas

• This role does not setup the initial connection of your Ansible machine to the configured hosts.
• This role rehashes the host names in ~/.ssh/known_hosts, which is the default in debian/ubuntu. If you use and rely on unhashed hostnames in this file, disable it by setting ssh_known_hosts_rehash to false.