- Add PendingUpdates and PendingUpdatesCheckedAt fields to Node model
- Add GetNodePendingUpdates method to Proxmox client (calls /nodes/{node}/apt/update)
- Add 30-minute polling cache to avoid excessive API calls
- Add pendingUpdates to frontend Node type
- Add color-coded badge in NodeSummaryTable (yellow: 1-9, orange: 10+)
- Update test stubs for interface compliance
Requires Sys.Audit permission on Proxmox API token to read apt updates.
Two critical fixes to prevent test timeouts:
1. Nil map panic in TestPollPVEInstanceUsesRRDMemUsedFallback:
- Test monitor was missing nodeLastOnline map initialization
- Panic occurred when pollPVEInstance tried to update nodeLastOnline[nodeID]
- Caused deadlock when panic recovery tried to acquire already-held mutex
- Added nodeLastOnline: make(map[string]time.Time) to test monitor
2. Alert manager goroutine leak in Docker tests:
- newTestMonitor() created alert manager but never stopped it
- Background goroutines (escalationChecker, periodicSaveAlerts) kept running
- Added t.Cleanup(func() { m.alertManager.Stop() }) to test helper
These fixes resolve the 10+ minute test timeouts in CI workflows.
Related to workflow run 19281508603.
Three categories of fixes:
1. Goroutine leak causing 10-minute timeout:
- Add defer mon.notificationMgr.Stop() in monitor_memory_test.go
- Background goroutines from notification manager weren't being stopped
2. Database NULL column scanning errors:
- Change LastError from string to *string in queue.go
- Change PayloadBytes from int to *int in queue.go
- SQL NULL values require pointer types in Go
3. SSRF protection blocking test servers:
- Check allowlist for localhost before rejecting in notifications.go
- Set PULSE_DATA_DIR to temp directory in tests
- Add defer nm.Stop() calls to prevent goroutine leaks
Fixes for preflight test failures in workflow run 19280879903.
Related to #553
## Problem
LXC containers showed inflated memory usage (e.g., 90%+ when actual usage was 50-60%,
96% when actual was 61%) because the code used the raw `mem` value from Proxmox's
`/cluster/resources` API endpoint. This value comes from cgroup `memory.current` which
includes reclaimable cache and buffers, making memory appear nearly full even when
plenty is available.
## Root Cause
- **Nodes**: Had sophisticated cache-aware memory calculation with RRD fallbacks
- **VMs (qemu)**: Had detailed memory calculation using guest agent meminfo
- **LXCs**: Naively used `res.Mem` directly without any cache-aware correction
The Proxmox cluster resources API's `mem` field for LXCs includes cache/buffers
(from cgroup memory accounting), which should be excluded for accurate "used" memory.
## Solution
Implement cache-aware memory calculation for LXC containers by:
1. Adding `GetLXCRRDData()` method to fetch RRD metrics for LXC containers from
`/nodes/{node}/lxc/{vmid}/rrddata`
2. Using RRD `memavailable` to calculate actual used memory (total - available)
3. Falling back to RRD `memused` if `memavailable` is not available
4. Only using cluster resources `mem` value as last resort
This matches the approach already used for nodes and VMs, providing consistent
cache-aware memory reporting across all resource types.
## Changes
- Added `GuestRRDPoint` type and `GetLXCRRDData()` method to pkg/proxmox
- Added `GetLXCRRDData()` to ClusterClient for cluster-aware operations
- Modified LXC memory calculation in `pollPVEInstance()` to use RRD data when available
- Added guest memory snapshot recording for LXC containers
- Updated test stubs to implement the new interface method
## Testing
- Code compiles successfully
- Follows the same proven pattern used for nodes and VMs
- Includes diagnostic snapshot recording for troubleshooting
