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Site Pools

Site Pools distribute hosts automatically across a set of Checkmk monitoring sites — useful when a location is split across several remote sites for load reasons and you want the hosts spread evenly, without mapping each host to a site by hand.

Go to: Modules → Checkmk → Pools → Site Pools

How It Works

A Site Pool is a named group of Checkmk site ids. When a host matches a Site Pool rule, the Syncer places it on the site of that pool with the fewest hosts (least-loaded). The assignment is sticky: once a host is on a site it keeps it on later syncs, so hosts do not move around between sites. When a host no longer matches the pool rule, its seat is freed automatically.

The site is written to the host's site attribute in Checkmk — the same attribute the Monitored on Site action sets, just picked automatically and balanced across the pool.

Configuration

Create a Site Pool entry with:

  • Name — used to reference the pool in export rules
  • Member Sites — the Checkmk site ids that make up the pool (e.g. berlin_1, berlin_2, berlin_3). Import your sites first (Import Sites) so you know the exact ids.
  • Enabled — only enabled pools hand out sites

The hosts taken counter next to each member site is maintained by the Syncer and is read-only.

Using a Pool in Export Rules

In an export rule, use the Site Pool action and reference the pool by name:

berlin

The action parameter supports Jinja, so you can build the pool name from host attributes (e.g. {{location}}). When you pick the action, the rule form suggests the pools you have already defined as one-click chips — or warns you when none exist yet.

Note

Make sure a host matches only one Site Pool rule. Use the Last Match option to prevent unintended stacking with other site assignments.

Sync Command

The seat counters are kept up to date on every export. To recount them from the current host assignments without running a full export (for example after manual changes):

./cmdbsyncer checkmk sync_sitepools

This also runs as the cron job Checkmk: Sync Site Pools.

Site Pools vs. Folder Pools

Both spread hosts for load balancing, but on different axes:

  • Folder Pools distribute hosts across Checkmk folders (by seat count), which you then link to sites in Checkmk.
  • Site Pools distribute hosts directly across Checkmk sites (least-loaded), independent of the folder a host lands in.

Pick Site Pools when you want to balance the site attribute itself and keep your folder structure driven by other rules.