Installs Nagios, NRPE (both client and server), and configures Nagios automatically based on Ansible's existing inventory of hosts. The goal is to have a complete Nagios monitoring system in a single Ansible role, and without too much manual configuration required.

Make sure that DNS or /etc/hosts name resolution is working. For example that you can ping web3 at web3.example.com. Email is a recommended prerequisite, with choices of Exim, Postfix, and others.

All the variables in the defaults/ directory may be overridden or changed.

The default ansible inventory group monitoring-servers can be customized with the nagios_monitoring_servers_group_name variable.

If the variable nagios_host_name is defined for a host this value will be used for the host_name attribute in hosts and services definitions.

Add users who should be allowed to login to the Nagios web GUI in the nagios_users variable:
nagios_users:

• user: nagiosadmin
  pass: Password1change
  email: [email protected]

Another and better way to add both nagios contacts and nagios admins is the users variable, compatible with https://github.com/mivok/ansible-users

This playbook will look for users in the sysadmin group and those will become nagios admins.

Create the users var, a good place is group_vars/all. Here is an example.

users:

• username: foo
  name: Foo Barrington
  groups: ['sysadmin']
  uid: 1001
  ssh_key:
  • "ssh-rsa AAAAA.... foo@machine"
  • "ssh-rsa AAAAB.... foo2@machine"
    htpasswd: $apr1$SheSL4Et$xry6RljdWWvUVrh42s7OA0
    nagios:
    pager: "[email protected]"
    email: "[email protected]"

Where did that htpasswd value come from? Generate the htpasswds manually, and then paste them into users.
htpasswd -n mario
mario:$apr1$SheSL4Et$xry6RljdWWvUVrh42s7OA0

You must configure at minimum one sysadmin user, as just explained, or nagios contacts won't work.

The nagios commands are in the nagios_commands variable, see defaults/main.yml. You can add more commands by adding to, or overriding, the variable.

The nagios services are currently in the "checks" per hostgroup variables, see defaults/main.yml. You can add more services by adding to, or overriding, the variable.

You can define a list of custom check scripts in the nagios_custom_checks variable. Files with these names will be templated to the nrpe_client_plugins_dir directory on the Nagios server and can be used in commands and local services definitions.

Ansible hosts in the 'all' group are converted to nagios monitored hosts. No configuration required.

Ansible groups are converted to nagios hostgroups. No configuration required.

The following values are set in defaults/main.yml :

nagios_hosts_ignore: ""
nagios_groups_ignore: ""

They can be overridden to include Hosts or Hostgroups that should be skipped entirely. Examples:

nagios_hosts_ignore:
  - host1_skip_this_host
nagios_groups_ignore:
  - hostgroup_dev_to_skip
  - and_this_one

This determines which hosts the nagios server will ignore/skip, because these hosts will be excluded from the configs.

Another consideration is whether the ansible playbook should run on all servers. The example playbook test.yml has "- hosts: all", which installs the nagios client on all known servers. You could adjust your top-level playbook and set a different "hosts: " directive. However it's probably fine to install the monitoring client on all servers.

Refer to test.yml in the root of this role.

To install the client:
roles:
- { role: 'sdarwin.nagios', run_nagios_client: true }

To install the server:
roles:
- { role: 'sdarwin.nagios', run_nagios_server: true }

Add nagios servers to the monitoring-servers group in the Ansible inventory.

BSD

By Sam Darwin, 2016. Based on pre-existing roles, see ACKNOWLEDGEMENTS.md file. Feedback and bug reports welcome.