CleanupAlertsForNodes removes alerts whose Node isn't in
existingNodes. That map is built upstream only from state.Nodes
(Proxmox nodes) and state.PBSInstances (PBS instances) — no agent
resources. Agent-sourced alerts (Unraid, standalone Linux hosts,
TrueNAS, anything reached via Pulse Agent) typically have Node=""
or an agent UUID, so they fall into the cleanup branch every
cycle. Then the next poll re-creates the alert as new, calls
AddAlert, and appends a fresh history row. Observed in the wild:
3,980 alert history entries in 7 days, with the same canonical
alert ID (e.g. "Unraid array running without parity protection")
appearing every 30 seconds.
Adds a carve-out for ResourceID prefixes starting with "agent:",
matching the existing pattern for "docker-" / "docker:" and
"pbs-" / "pbs-offline". Locks in the behaviour with a new subtest
that mixes agent-sourced and Proxmox-sourced alerts and asserts
that only the legitimately stale Proxmox alert is removed.
rcourtman
113190a920