Too many open files


I am running Icinga on Centos 8.2.2004, i’m seeing an issue where icinga is crashing each day and in icinga2.log it only says: critical/ApiListener: Cannot accept new connection: Too many open files

Does anyone know how to resolve this?


Do you have pending signing requests on the master?
If I understand this open bug at github correctly this can be a problem:

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Hello and welcome to the community @qvindesland!

Did you make any progress with this?

I would love to hear back from you and whether the issue linked by log1c applied to you (if you’re running Icinga 2.10 that would probably be it)

Have a nice day,


i guess the issue still persists.

we have in our infrastructure the same issue. We running two Icinga2-servers (CentOS 7) with version icinga2-2.13.2-1 installed.

We increased the open file limit for the system to 65535
and under the /etc/sysconfig/icinga2 the RLIMIT also to 65535.

But increasing the file limits doesn´t solved the problem, because the openfiles only increase then to the next open file limit. After restart of icinga2-service the open files are cleaned, but only till the limit is reached again.

what we found out is that the established connections between the icinga-server and the clients are not closed.

for example:

sudo netstat -antp | grep icinga2

tcp        0      0    ESTABLISHED 109943/icinga2
tcp        0      0    ESTABLISHED 109943/icinga2

is there a possibilty to set a timeout for the connections or has to be fixed in the softwarepackage ?