Fix: Avoid Linux Agent timeouts when systemd-timedated doesn't run

[mueller-ma]

General information

See https://forum.checkmk.com/t/linux-agent-issues-with-systemd-timedated-service-creates-timeouts/52259 for context

Bug reports

When the Linux agents checks systemd-timesync, it calls timedatectl show:

checkmk/agents/check_mk_agent.linux

Line 1631 in 86cbbd3

timedatectl show | awk '/Timezone/{print $0}'

When the service systemd-timedated.service doesn't run, the command times out and blocks the agent out for ~25 seconds:

# time timedatectl show
Failed to parse bus message: Connection timed out

real    0m25.020s
user    0m0.000s
sys     0m0.006s
# systemctl status systemd-timedated.service
● systemd-timedated.service - Time & Date Service
     Loaded: loaded (/lib/systemd/system/systemd-timedated.service; static)
     Active: failed (Result: exit-code) since Wed 2025-02-12 15:35:38 CET; 7s ago

25 seconds is nearly half of the default 60 seconds agent timeout, so the agent reaches this timeout sometimes when systemd-timedated is down.

Proposed changes

Add a timeout call to reduce the timeout from timedatectl show from ~25 seconds to 5 seconds.