Merge pull request #5275 from Icinga/fix/docs-systemd-max-tasks

Add troubleshooting hints for cgroup fork errors

refs #4918
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Michael Friedrich 2017-05-19 15:27:23 +02:00 committed by GitHub
commit 24bcacb631
1 changed files with 28 additions and 0 deletions

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@ -307,6 +307,34 @@ Fetch all check result events matching the `event.service` name `random`:
$ curl -k -s -u root:icinga -X POST 'https://localhost:5665/v1/events?queue=debugchecks&types=CheckResult&filter=match%28%22random*%22,event.service%29'
### <a id="check-fork-errors"></a> Check Fork Errors
We've learned that newer kernel versions introduce a [fork limit for cgroups](https://lwn.net/Articles/663873/)
which is enabled in SLES 12 SP2+ for example. The default value
for `DefaultTasksMax` in Systemd is set to `512`.
Icinga 2 relies on forking child processes to execute commands
and might therefore hit this limit in larger setups.
The error message could look like this:
2017-01-12T11:55:40.742685+01:00 icinga2-master1 kernel: [65567.582895] cgroup: fork rejected by pids controller in /system.slice/icinga2.service
In order to solve the problem, increase the value for `DefaultTasksMax`
or set it to `infinity`:
[root@icinga2-master1.localdomain /]# vim /usr/lib/systemd/system/icinga2.service
[Service]
DefaultTasksMax=infinity
[root@icinga2-master1.localdomain /]# systemctl daemon-reload
[root@icinga2-master1.localdomain /]# systemctl restart icinga2
Please note that this setting is available since Systemd version 226.
### <a id="late-check-results"></a> Late Check Results
[Icinga Web 2](https://www.icinga.com/products/icinga-web-2/) provides