ssh

An Ansible role for managing ssh clients configuration.

Requirements

This role should work on any system that provides openssh client and is
supported by ansible. The role was tested on:

Role Variables

By default, the role should not modify the system configuration and generate
global ssh_config that matches OS default (the generated configuration does
not keep comments and order of the options).

ssh_user

By default (null) the role will modify the global configuration for all
users. Other values will be interpreted as a username and the role will
modify per-user configuration stored under ~/.ssh/config of the given user.
The user needs to exist before invoking this role otherwise it will fail.

ssh_skip_defaults

By default (auto), the role writes the system-wide configuration file
/etc/ssh/ssh_config and keeps OS defaults defined there (true). This is
automatically disabled, when a drop-in configuration file is created
(ssh_drop_in_name!=null) or when per-user configuration file is created
(ssh_user!=null).

ssh_drop_in_name

This defines the name for the drop-in configuration file to be placed in
system-wide drop-in directory. The name is used in the template
/etc/ssh/ssh_config.d/{name}.conf to reference the configuration file to
be modified. If the system does not support drop-in directory, setting this
option will make the play fail. Default is null if the system does not
support drop in directory and 00-ansible otherwise.

The suggested format is NN-name, where NN is two-digit number used for
sorting the and name is any descriptive name for the content or the owner
of the file.

ssh dict

A dict containing configuration options and respective values. See example
below.

Simple variables consisting of the option name prefixed with ssh_ can be
used rather than a dict above. The simple variable overrides values in dict
above.

ssh_additional_packages

This role automatically installs packages needed for most common use cases
on given platform. If some additional packages need to be installed (for
example openssh-keysign for host-based authentication), they can be specified
in this variable.

ssh_config_file

The configuration file that will be written by this role. The default is
defined by template /etc/ssh/ssh_config.d/{name}.conf if system has drop-in
directory or /etc/ssh/ssh_config otherwise. If ssh_user!=null, the
default is ~/.ssh/config.

To write /etc/ssh/ssh_config even if a drop-in directory is supported, set
ssh_drop_in_name to null.

ssh_config_owner, ssh_config_group, ssh_config_mode

The owner, group and mode of the created configuration file. The files are
owned by root:root with mode 0644 by default, unless
ssh_user!=null. In that case, the mode is 0600 and owner and
group are derived from username given in ssh_user variable.

ssh_backup

When set to false, the original ssh_config file is not backed up. Default is true.

Example Playbook

The following playbook configures the root user ssh configuration in his

home directory to use compression, control-master multiplexing and enable
GSSAPI authentication in the “match final all” block. Additionally, it
creates alias “example” for connecting to the example.com host as a user
somebody. The last line disables X11 forwarding.

- name: Manage ssh clients
  hosts: all
  tasks:
  - name: Configure ssh clients
    include_role:
      name: linux-system-roles.ssh
    vars:
      ssh_user: root
      ssh:
        Compression: true
        # wokeignore:rule=master
        ControlMaster: auto
        ControlPath: ~/.ssh/.cm%C
        Match:
          - Condition: "final all"
            GSSAPIAuthentication: true
        Host:
          - Condition: example
            Hostname: example.com
            User: somebody
      ssh_ForwardX11: false

More examples are in the examples/ directory.

License

LGPLv3, see the file LICENSE for more information.

Author Information

Jakub Jelen, 2021 - 2022