check_chef_stale

Alerting for stale nodes on Chef with Nagios/Icinga

Installation

1. copy plugin check_chef_stale.rb to /usr/lib/nagios/plugins
2. copy command definition and service template definition check_chef_stale.cfg to /etc/nagios/plugins.
3. create check definition like this:

define service {
    use                     chef_stale
    host_name               localhost
}       

NOTE: the paths may vary, depending on your Nagios/Icinga installation.

Known Issues

chef/http/auth_credentials.rb:40:in `signature_headers': Cannot sign the request without a client name, check that :node_name is assigned (ArgumentError)

ensure node_name is defined in chef config. If you use chef-client cookbook, then it omits writing node_name to config if it's the default (# Using default node name (fqdn)). you can workaround this by creating /etc/chef/client.d/nodename.rb:

# needed for check_chef_stale.rb
Chef::Config[:node_name] = 'nagios.fqdn.example.org'

---

[2016-02-03T13:49:00+02:00] WARN: Failed to read the private key /etc/chef/client.pem: #<Errno::EACCES: Permission denied - /etc/chef/client.pem>

ensure the files are accessible by user running the checks:

chmod a+r /etc/chef/client.d/nodename.rb
chown nagios /etc/chef/client.pem