Icinga2 Notifications: 101

Problem

• Email notifications in Icinga2 for your hostgroup
• You can’t find a quick ’n dirty method

Pre-Reqs

• Installation of Icinga2
• Configured some hosts, hostgroups and services

So how do I do it?

Making sure mail works

1. Install ssmtp

yum install ssmtp

2. Disable postfix and stop the service

systemctl disable postfix
systemctl stop postfix

3. Configure your ‘finger’ information.

chfn -f name-you-want-as-displayname loginname

4. Configure ssmtp

#
# /etc/ssmtp.conf -- a config file for sSMTP sendmail.
#
# Recipient for all mail to userids < 100
root=postmaster

# The place where the mail goes.
mailhub=smtp.example.com

# Where will the mail seem to come from? This would be the part after the @
RewriteDomain=example.com

# Set this to never rewrite the "From:" line (unless not given) and to
# use that address in the "from line" of the envelope.
FromLineOverride=YES

5. Start and enable service

systemctl enable ssmtp
systemctl start ssmtp

6. Test this

echo "Hello, this is a test" | mail -s "Test" [email protected]

Configure icinga2 user (and usergroups)

By default, icinga2 comes with a UserGroup called ‘icingaadmins’. Any user of this group will receive email notifications if the icinga2 host itself has issues.

Please note that an icinga2 user is not necessarily an icingaweb2 login user. This is a whole different topic.

A simple user looks like this:

object UserGroup "icingaadmins" {
	display_name = "Icinga 2 Admin Group"
}
 
object User "TestUser" {
  display_name = "A Name"
  groups = [ "icingaadmins" ]
  email = "[email protected]"
  period = "24x7"
  states = [ OK, Warning, Critical, Unknown ]
  types = [ Problem, Recovery ]
}

If you need more information on the attributes just have a look at the documentation.

Assign Notification to Service and User

But if you want mails for hosts or services you have to use assign (see documentation).

In the following example I assign the command mail-service-notification (defined in “/etc/icinga2/scripts/”) to every service, which runs on the host named “Host1”. A notification will only be sent once a state change is detected. (“interval = 0”)

apply Notification "Notify-Test" to Service {
  command = "mail-service-notification"
  users = ["TestUser"]
  interval = 0
  assign where service.host_name == "Host1"
}