CitadelPlatform monitoring
Monitor platform health, capacity, statistics, and stale data.
Citadel reports CPU, memory, network, and Docker storage filesystem usage for Local, regular Agent, and Platform Edge Agent connections.
Container memory
The Containers table's Memory column shows usage excluding reported file cache, followed by the memory limit. Container and Stack Stats show that same Usage value and Cache separately:
Usage = raw container memory − reported file cache
Cache = reported file cacheUsage may be lower than Linux docker stats, which excludes only inactive file
cache. If Docker does not report cache, no cache is subtracted.
Disk Usage
Disk Usage is the capacity of the host filesystem containing Docker's configured data root. It is not the sum of image, container, volume, and build cache sizes, and it does not represent reclaimable Docker space.
Citadel shows current used and total capacity in the Platform summary and historical percentage usage in the Platform Stats tab. Missing readings appear as unavailable rather than zero.
Citadel includes these system rules:
| Rule | Severity | Required matches | Cooldown |
|---|---|---|---|
| Disk above 70% | Warning | 3 | 300 seconds |
| Disk above 90% | Critical | 3 | 300 seconds |
Backup Summary
The platform summary counts backup policies attached to that platform through a Docker volume, stack, deployment, or managed Swarm Service. Citadel control-plane backups are instance-wide, so they are shown on the main Backups page and are not included in a platform's total. See Backups for details.
Container Mount
Linux Core and Platform Agent containers need this bind mount:
/:/host:roThe mount lets Citadel read filesystem capacity for Docker's configured data root, including a custom data root on another mounted filesystem. It is read-only, but it exposes host paths to the trusted Citadel process. Citadel does not browse or transfer host files through this feature.
Removing the mount disables only disk metrics. CPU, memory, network, and Docker operations continue. Older Agent containers must be upgraded and recreated with the mount. Build-pool-only Edge Agents do not need it.
Custom packaging can change the in-container mount location with:
CITADEL_HOST_ROOT=/hostThe environment value and actual bind target must match.
For ZFS, Citadel reports the mounted dataset or filesystem containing Docker's data root, not whole-pool allocation.