Ansible Role: SSH config

The SSH config role creates a SSH config file for an inventory containing all inventory hosts.

Especially useful for cloud environments where you cannot know in advance which IP will be assigned to the instance. The role helps to write this IP to an SSH configuration file so that you don't have to remember it.

Requirements

Configure SSH to also include configs under ~/.ssh/conf.d:

# Canonicalize Hostnames to use Host *.XXX stanzas below without
# the need to always use the FQDN when connecting
CanonicalizeHostname yes
Include conf.d/*

Installation

Via requirements.yml:

---
# file: requirements.yml
roles:
  - name: ngine_io.ssh_config
    version: v0.2.0

To install:

ansible-galaxy install -r requirements.yml

Role Variables

ssh_config__env: "{{ inventory_file }}"

The name of the environment the SSH config file is named after.

ssh_config__dest_path: "~/.ssh/conf.d"

The path where the config is stored.

ssh_config__configs:
  - Hostname {{ ansible_host | default(inventory_hostname) }}
  - Port {{ ansible_port | default(22) }}
  - User {{ ansible_user | default(lookup('env', 'USERNAME')) }}
  - StrictHostKeyChecking accept-new

The SSH config fragment for each host entry.

Dependencies

None.

Example Playbook

Imaging we have a role hcloud which creates instances based on our inventory and registers the IP of it as ansible_host.

---
- hosts: cloud
  gather_facts: false
  connection: local
  roles:
    - role: hcloud
      tags: hcloud
    - role: ssh_config
      tags: ssh_config
  post_tasks:
    - name: Waiting for SSH to come up
      wait_for:
        port: 22
        host: "{{ ansible_host }}"
        search_regex: OpenSSH
        delay: 2

Assuming we are having an inventory prod like so:

[prod:children]
cloud  ssh_config__env=prod

[cloud]
prod-web1
prod-web2

As a result we would get a config in ~/.ssh/conf.d/ssh_config_prod.conf like:

### Autogenerated, do not modify ###

Host prod-web1
    Hostname 1.2.3.4
    Port 22
    User ansible

Host prod-web2
    Hostname 1.2.3.5
    Port 22
    User ansible

Then you just SSH-into the instance like so:

ssh prod-web1

License

MIT / Apache2

Author Information

This role was created in 2022 by René Moser.