Satellite node capacity assessment

Icinga 2
, ,
#1

Hello,

In a single zone only two satellite nodes are supported. Is this still true with 2.11.x version?

Is there a way to assess the capacity of a single Satellite node so as in able to service without overloading it in some way? something one can monitor via some stats?

Seeking advise about Satellites running NRPE only and one with Icinga2 agent.

Thanks

#2

The limitation to maximum two nodes is still a given thing and I have not seen any effort spend on changing this.

To prevent overloading the satellite with checks you have the MaxConcurrentChecks constant. To get some metrics for check execution you can use the icinga check, so it should help to tailor the value, but keep in mind hitting it will result in latency and if one high available node goes down the other has to handle all checks.

This is especially useful if the satellite does many checks on its own (the NRPE ones) and less useful if it only schedules checks on agents (the one with Icinga 2). For the later one network connections is the limiting factor (because of open files) and load comes from initializing connections so better initiate them from the agents.

#3

Thanks for your response. I see the performance metrics provided by the “icinga” check for a zone which is setup on the Masters. However I’m looking for similar performance metrics for every satellite node in a every zone.

Please explain the network connections/ Open files limitations you meant for me.

Thanks.

#4

You can use the icinga check on every instance. For master and satellite it makes sense for metrics and failures of last reload, on agents I do not care about metrics but failed reloads and minimum version are great to check.

For every connection a socket has to be kept open, this can result in hitting the open file limit. The limit can be set in /etc/security/limits.conf or better in the systemd unit. Defaults are sane, but I had to increase it in larger environments in the past.