Werk #20175: Run active checks on relays
| Component | Relay | ||||
| Title | Run active checks on relays | ||||
| Date | Aug 18, 2026 | ||||
| Level | Prominent Change | ||||
| Class | New Feature | ||||
| Compatibility | Incompatible - Manual interaction might be required | ||||
| Checkmk versions & editions |
|
Relays can now run active checks for the hosts they monitor. Until now a relay only ran SNMP and special-agent checks. The relay now executes these active checks itself, from inside the host's network, and forwards the results to your site.
Current active checks supported in this release:
- Check hosts with ping (ICMP echo request)
- Check HTTP web service
- Check certificates
You configure them with the usual rules: nothing relay-specific is needed. Other active checks are not supported yet on relays and are not created for relay-monitored hosts.
The relay uses a specific pool of processes to run active checks. You can size it per relay on its setup page.
Action required for ICMP on existing relays
check_icmp needs the NET_RAW Linux kernel capability, which current podman versions no longer grant by default. Relays installed with 2.5.0p15 or later get it automatically. Relays installed with earlier versions do not.
If your relay was installed before 2.5.0p15, you are probably affected. See this knowledge base article to fix it. The regular relay update does not fix this.