Can't get notifications to work in icinga docker

Icinga Web Modules Icinga Director
1

I am very new to Icinga and have struggled to get where I am by following online guides. I have successfully setup all my hosts and services but I am now struggling with notifications. I followed this to get Icinga up and running (Icinga Docker Setup Made Easy with Docker Compose | Tutorial). I think I have properly set everything up for a notification for both hosts and services but when I try to apply the notification to a host or service, I get this error:

[2026-02-07 11:47:58 +0000] information/cli: Icinga application loader (version: v2.15.1)
[2026-02-07 11:47:58 +0000] information/cli: Loading configuration file(s).
[2026-02-07 11:47:58 +0000] information/ConfigItem: Committing config item(s).
[2026-02-07 11:47:58 +0000] information/ApiListener: My API identity: Icinga2
[2026-02-07 11:47:58 +0000] critical/config: Error: Validation failed for object 'DesktopMasterBedroom!Notifications HOST' of type 'Notification'; Attribute 'command': Object 'mail-service-notification' of type 'NotificationCommand' does not exist.
Location: in [stage]/zones.d/master/notification_templates.conf: 2:5-2:41
[stage]/zones.d/master/notification_templates.conf(1): template Notification "HOST Notifications" {
[stage]/zones.d/master/notification_templates.conf(2):     command = "mail-service-notification"
                                                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[stage]/zones.d/master/notification_templates.conf(3):     period = "Always"
[stage]/zones.d/master/notification_templates.conf(4):     states = [ Down, Up ]

Any assistance would be greatly appreciated

Thanks

2

So I have made some progress today as I now see notifications being sent under history. This is what I did:

cd /etc/icinga2/zones.d
mkdir master
cd master
cp /etc/icinga2/conf.d/commands.conf /etc/icinga2/zones.d/master/commands.conf

Curious if this will persist docker starts and stops?

Now I am getting the error:

terminated with exit code 1, output: mail: cannot send message: Process exited with a non-zero status

I have Exim4 configured on the host and it works fine. I also have bsd-mailx installed as I think it installs with Exim4. mail, Mail, and mailx are all symlinked to /usr/bin/bsd-mailx

3

You probably don’t have a mailserver (exim) running in the container, do you?

You’ll need an SMTP forwarder instead. I usually use SSMTP for this in my docker containers.

4

Thank you for this response @adn77 as this is likely my issue. I have a couple questions if you could be so kind. 1) If install ssmtp inside the container, do I need to do anything to make the installation persist reboots of the host or restarts of the container 2) Do I configure ssmtp to forward mail to exim4 on the host or straight to the gmail smtp server

thanks

5

If you want the ICINGA2 container to send mail, you will already find MSMTP installed in the image:

To notify by e-mail, provide an msmtp configuration - either by mounting the /etc/msmtprc file or by specifying the desired content of ~icinga/.msmtprc via the environment variable MSMTPRC.

:slight_smile:

As to the second question, it depends on your local mail sending policy… I usually use a local smarthost in our network.

6

so, I created a docker volume

home/myuser/docker/docker-compose-icinga/.msmtprc:/etc/msmtprc/.msmtprc

created the .msmtprc file:

## Set default values for all following accounts.
#defaults
#auth           on
#tls            on
#tls_trust_file /etc/ssl/certs/ca-certificates.crt
#logfile        ~/.msmtp.log

# Gmail
account        gmail
host           smtp.gmail.com
port           587
tls_starttls   on
from           user@gmail.com
user           user
password       app-password

## A freemail service
#account        freemail
#host           smtp.freemail.example
#from           joe_smith@freemail.example
#...

## Accounts can inherit info from another account
#account        postmasterfreemail : freemail
#from           postmaster*@freemail.example

# Set a default account
account default: gmail

then I try to send mail from inside the container using:
mail -s "Icinga Raspi 5 Test" gmailuser@gmail.com

and I get cannot send message: Process exited with a non-zero status

7

I wonder if I need to map port 587 in my docker-compose?

edit: that didn’t help, same error

8

I have mail working inside the container now. I can send mail using the mail -s "test" user@gmail.com. Icinga shows notification history indicating notifications are being generated but I still get the cannot send message: Process exited with a non-zero status inside the container when reviewing docker logs.

9

Posting my notification settings to see if anyone sees anything out of the ordinary

template User "generic-host-notifications" {
    enable_notifications = true
    states = [ Down, Up ]
    types = [
        DowntimeEnd,
        DowntimeStart,
        FlappingEnd,
        FlappingStart,
        Problem,
        Recovery
    ]
}

object User "user1" {
    import "generic-host-notifications"

    display_name = "User HOST"
    email = "user@gmail.com"
    period = "Always"
}

template Notification "HOST Notifications" {
    command = "mail-host-notification"
    period = "Always"
    states = [ Down, Up ]
    types = [ DowntimeEnd, DowntimeStart, FlappingEnd, FlappingStart ]
    users = [ "user1" ]
}

apply Notification "Notifications HOST" to Host {
    import "HOST Notifications"

    assign where host.vars.NodeType == "linux1" 
    states = [ Down, Up ]
    types = [
        DowntimeEnd,
        DowntimeRemoved,
        DowntimeStart,
        FlappingEnd,
        FlappingStart
    ]
    users = [ "user1" ]
}

object TimePeriod "Always" {
    import "legacy-timeperiod"
    display_name = "24x7"
    ranges = {
        "friday"	= "00:00-24:00"
        "monday"	= "00:00-24:00"
        "saturday"	= "00:00-24:00"
        "sunday"	= "00:00-24:00"
        "thursday"	= "00:00-24:00"
        "tuesday"	= "00:00-24:00"
        "wednesday"	= "00:00-24:00"
    }
}