# pve-local-exporter

Prometheus exporter for Proxmox VE that collects VM and storage metrics directly from the host without using the PVE API. Written in Go.

Metrics are gathered by reading `/proc`, `/sys`, `/etc/pve`, and running `qm monitor` commands.

> **Disclaimer:** This is a heavily vibe-coded rewrite of [pvemon](https://github.com/illustris/pvemon) for better maintainability and easier distribution. This disclaimer will remain up until the codebase has been reviewed and validated.

## Building

Requires [Nix](https://nixos.org/):

```sh
nix build               # build static binary
nix flake check         # evaluate flake + run go vet
```

The output binary is statically linked (`CGO_ENABLED=0`).

## Development

```sh
nix develop                          # shell with go + gopls
nix develop -c go test ./... -race   # run tests with race detector
nix develop -c go vet ./...          # static analysis
```

Go source lives in `src/`. After changing `go.mod` dependencies, run `go mod tidy` then update `vendorHash` in `default.nix` (set to a bogus hash, run `nix build`, copy the correct hash from the error).

## Usage

```sh
pve_local_exporter [flags]
```

### Flags

| Flag | Default | Description |
|------|---------|-------------|
| `--port` | 9116 | HTTP listen port |
| `--host` | 0.0.0.0 | Bind address |
| `--collect-running-vms` | true | Collect KVM VM metrics |
| `--collect-storage` | true | Collect storage pool metrics |
| `--metrics-prefix` | pve | Prefix for all metric names |
| `--loglevel` | INFO | DEBUG, INFO, WARNING, ERROR |
| `--qm-terminal-timeout` | 10s | qm monitor command timeout |
| `--qm-max-ttl` | 600s | TTL cache for qm monitor data |
| `--qm-rand` | 60s | Jitter range for cache expiry |
| `--qm-monitor-defer-close` | true | Defer closing unresponsive qm sessions |
| `--version` | | Print version and exit |

## Exported metrics

All metric names are prefixed with the configured `--metrics-prefix` (default `pve`).

### Per-VM metrics

| Metric | Type | Labels | Description |
|--------|------|--------|-------------|
| `_kvm_info` | gauge | id, name, cpu, pid, pool, pool_levels, pool1, pool2, pool3 | VM info (value 1) |
| `_kvm_cpu_seconds_total` | counter | id, mode | KVM CPU time (mode: user, system, iowait) |
| `_kvm_vcores` | gauge | id | vCores allocated |
| `_kvm_maxmem_bytes` | gauge | id | Maximum memory in bytes |
| `_kvm_memory_percent` | gauge | id | Memory percent of host |
| `_kvm_memory_extended` | gauge | id, type | Extended memory info from /proc status (vmrss, vmpeak, etc.) |
| `_kvm_threads` | gauge | id | Threads used |
| `_kvm_ctx_switches_total` | counter | id, type | Context switches (type: voluntary, involuntary) |
| `_kvm_io_read_count_total` | counter | id | Read system calls by KVM process |
| `_kvm_io_read_bytes_total` | counter | id | Bytes read from disk by KVM process |
| `_kvm_io_read_chars_total` | counter | id | Bytes read including buffers by KVM process |
| `_kvm_io_write_count_total` | counter | id | Write system calls by KVM process |
| `_kvm_io_write_bytes_total` | counter | id | Bytes written to disk by KVM process |
| `_kvm_io_write_chars_total` | counter | id | Bytes written including buffers by KVM process |
| `_kvm_nic_info` | gauge | id, ifname, netdev, queues, type, model, macaddr | NIC info (value 1) |
| `_kvm_nic_queues` | gauge | id, ifname | NIC queue count |
| `_kvm_nic_{stat}_total` | counter | id, ifname | Per-NIC sysfs counters (rx_bytes, tx_bytes, rx_packets, etc.) |
| `_kvm_disk_info` | gauge | id, disk_name, block_id, disk_path, disk_type, vol_name, pool, pool_name, cluster_id, vg_name, device, attached_to, cache_mode, detect_zeroes, read_only | Disk info (value 1) |
| `_kvm_disk_size_bytes` | gauge | id, disk_name | Disk size in bytes |

### Storage metrics

| Metric | Type | Labels | Description |
|--------|------|--------|-------------|
| `_node_storage_info` | gauge | (dynamic, varies by storage config) | Storage pool info (value 1) |
| `_node_storage_size_bytes` | gauge | name, type | Storage total size in bytes |
| `_node_storage_free_bytes` | gauge | name, type | Storage free space in bytes |

### Operational metrics

| Metric | Type | Labels | Description |
|--------|------|--------|-------------|
| `_scrape_duration_seconds` | gauge | | Duration of metrics collection |
| `_exporter_build_info` | gauge | version | Build information (value 1) |

## Architecture

All I/O is behind interfaces for testability. No test touches the real filesystem or runs real commands.

```
src/
  main.go                          HTTP server, signal handling
  internal/
    config/                        CLI flag parsing
    cache/                         TTLCache (with jitter), MtimeCache (file change detection)
    procfs/                        /proc parsing: process discovery, CPU, IO, memory, threads
    sysfs/                         /sys reading: NIC stats, block device sizes
    qmmonitor/                     qm monitor pipe I/O + TTL cache, network/block parsers
    pveconfig/                     /etc/pve parsers: pools (user.cfg), storage (storage.cfg)
    storage/                       statvfs wrapper, zpool list parser
    collector/                     Prometheus Collector wiring all packages together
```

Concurrent NIC and disk collection uses a bounded goroutine pool (16 workers).

## License

See [LICENSE](LICENSE) if present.