Related to #630
Proxmox 8.3+ changed the VM status API to return the `agent` field as an
object ({"enabled":1,"available":1}) instead of an integer (0 or 1). This
caused Pulse to incorrectly treat VMs as having no guest agent, resulting
in missing disk usage data (disk:-1) even when the guest agent was running
and functional.
The issue manifested as:
- VMs showing "Guest details unavailable" or missing disk data
- Pulse logs showing no "Guest agent enabled, querying filesystem info" messages
- `pvesh get /nodes/<node>/qemu/<vmid>/agent/get-fsinfo` working correctly
from the command line, confirming the agent was functional
Root cause:
The VMStatus struct defined `Agent` as an int field. When Proxmox 8.3+ sent
the new object format, JSON unmarshaling silently left the field at zero,
causing Pulse to skip all guest agent queries.
Changes:
- Created VMAgentField type with custom UnmarshalJSON to handle both formats:
* Legacy (Proxmox <8.3): integer (0 or 1)
* Modern (Proxmox 8.3+): object {"enabled":N,"available":N}
- Updated VMStatus.Agent from `int` to `VMAgentField`
- Updated all references to `detailedStatus.Agent` to use `.Agent.Value`
- The unmarshaler prioritizes the "available" field over "enabled" to ensure
we only query when the agent is actually responding
This fix maintains backward compatibility with older Proxmox versions while
supporting the new format introduced in Proxmox 8.3+.
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
