HON95-wiki/config/automation/ansible.md

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title: Ansible breadcrumbs:

• title: Configuration
• title: Automation --- {% include header.md %}

Usage

General

• Specify SSH password: --ask-pass
• Specify sudo password: --ask-become-pass
• Specify username: --username=<username>
• Specify SSH key: --private-key=<key> (use /dev/null to explicitly avoid SSH keys)

Ad Hoc

• Basic usage: ansible {all|<target>} -i <inventory> [-m <module>] [-a <module-arg>]
  • To specify a hostname directly and not use an inventory file, specify all -i <host>, (with the comma).
  • To run locally, specift all -i localhost, --connection=local.
• Module examples:
  • Ping: ... -m ping
  • Run command (default module): ... -a <cmd>
  • Run complicated command (example): ... -a 'bash -c "nvidia-smi > /dev/null"'
• Get facts (with optional filter): ansible <...> -m setup -a 'filter=ansible_os_*' (example fact filter)

Playbooks

• Basic: ansible-playbook <playbook>
• Specify inventory file: ansible-playbook -i <hosts> <playbook>
• Limit which groups/hosts to use (comma-separated): ansible-playbook -l <group|host> <playbook>
• Limit which tasks to run using tags (comma-separated): ansible-playbook -t <tag> <playbook>

Vault

• Used to encrypt files and values. For values, just paste the !vault ... output directly into the configs to use the encrypted value in.
• Use file to keep password: Just add the password as the only line in a file, e.g. ~/.ansible_vault/<name> (with appropriate parent dir perms). A generated [a-zA-Z0-9]{32} string is more than strong enough.
• Encrypt, prompt for secret, using password file: ansible-vault encrypt_string --vault-password-file=~/.ansible_vault/stuff
• Use password file with playbook: ansible-playbook --vault-password-file=<file> <...>
• To avoid leaking secrets in logs and stuff, use no_log in tasks handling secrets.

Configuration

Config locations:

• Global: /etc/ansible/ansible.cfg
• User: ~/.ansible.cfg
• Project: ansible.cfg

Example config:

[defaults]
host_key_checking = false
#interpreter_python = auto
interpreter_python = /usr/bin/python3
#inventory = hosts.ini
#roles_path = ansible-roles:~/.ansible/roles:/usr/share/ansible/roles:/etc/ansible/roles

Templating

• YAML files:
  • Conditionals and stuff tend to mess up indentation. Specify #jinja2: trim_blocks:False to avoid that. This will also make the output a little uglier with empty lines in place of unsatisfied conditionals and stuff though.

Troubleshooting

Ansible Freezes when Connecting

Probably caused by a password-protected SSH key. Add --private-key=<keyfile> to specify which SSH key to use or --private-key=/dev/null to avoid using any SSH key.

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