Werk #15114: Avoid using systemd v219 and earlier if possible

Component Checks & agents
Title Avoid using systemd v219 and earlier if possible
Date Jan 23, 2023
Checkmk Edition Checkmk Enterprise (CEE)
Checkmk Version 2.0.0p33
Level Trivial Change
Class Bug Fix
Compatibility Compatible - no manual interaction needed

The agent package created by the agent bakery now prefers xinetd over systemd v219 if it is available. Version 219 and earlier do not provide the REMOTE_ADDR environment variable, which might result in dataloss.

In detail:

Users can configure the used network service for the Checkmk agent. They can choose to either use xinetd, systemd, or to prefer systemd, but fall back to xinetd if systemd is not available or not suitable.

The question which systemd is suitable depends on your configuration and use case:

  • If the ruleset Allowed agent access via IP address is configured, we require systemd v235 or newer.
  • If users want to monitor the host from more than one site we need at least systemd v220, or we risk dataloss.

Note that we cannot decide if the latter is the case by looking at the configuration.

The algorithm to decide which network service is best is improved as follows:

Prior to this werk: If the agent access ruleset is configured, we require systemd v235 or newer, otherwise any systemd version is used.

With this werk: We still require systemd v235 if the above ruleset is configured. If it is not, the order of preference is 1. systemd v220 or newer 1. xinetd 1. systemd v219 or older

We really don't recommend systemd v219 or earlier. We allow it as a last resort, because completely disallowing it would break existing installations of hosts that only have systemd v219 and no xinetd (RHEL, we're looking at you). If you are monitoring the host only on one site, or you use neither the hardware/software inventory nor logwatch, you're probably fine.

For Checkmk versions 2.1 and newer we only allow systemd v219 in combination with the agent controller, in which case there is no risk of dataloss.

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