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GridNMS Docs

Monitoring & Managing Collectors

Collectors are the workhorses that poll your devices and receive their logs and traps. GridNMS gives you two views into their health: a per-collector view for detail, and a fleet-wide view for an at-a-glance picture across every collector and background service.

The good news first: collectors keep themselves up to date automatically. There is nothing to patch or manually upgrade — when a new collector version is published, your collectors pick it up on their own. Your job is to keep an eye on health, not to maintain versions.

Per-collector health

Section titled “Per-collector health”

Go to Configure → Collectors. The list shows every registered collector with an Online or Offline indicator and when it was last seen.

A collector open on the Collectors page, showing its health tabs. Configure → Collectors. Each collector shows online/offline status; open one for its Health, Channels, and Plugins tabs.

Open a collector to see its detail tabs:

  • Health — live status and metrics: the collector’s version, when it last checked in, and usage bars for the work it’s doing.
  • Channels — the live state of each connection the collector uses. See Collector Channels for a full walkthrough.
  • Plugins — the status of each internal worker (described below).

Plugin status pills

Section titled “Plugin status pills”

A collector runs several internal workers, each shown as a coloured pill:

Plugin What it does
monitor Liveness checks — is each device up?
poller Collects metrics and details from devices.
syslog Receives syslog messages from devices.
trap Receives SNMP traps from devices.

Each pill shows a state:

State Meaning
Running (green) Working normally.
Starting (amber, pulsing) Coming up.
Stopped (grey) Not running — usually because that feature isn’t in use.
Crashed (red) Stopped unexpectedly. It generally restarts on its own; if a pill stays red, it needs attention.

Metric bars, last-seen, and stale detection

Section titled “Metric bars, last-seen, and stale detection”

The Health tab shows usage bars for the collector’s main jobs — devices monitored, syslog rate, and SNMP poll rate — each against the collector’s capacity. The bars turn amber as they approach the limit and red when they’re nearly maxed out, so you can spot a collector that’s running hot before it falls behind.

You’ll also see memory, uptime, and latency (the round-trip time between GridNMS and the collector).

A collector reports in with a heartbeat about once a minute. If GridNMS hasn’t heard from it in a couple of minutes, the last known figures are shown with a stale metrics warning. Stale metrics on an otherwise-online collector usually mean it’s under heavy load or its connection is unstable.

Fleet-wide view: Service Management

Section titled “Fleet-wide view: Service Management”

For the big picture, go to Configure → Service Management. This page shows the health of the background services that keep monitoring running, alongside collector status across your whole fleet — all on one screen.

The Service Management page showing service health and collector sessions. Configure → Service Management gives an at-a-glance view of background services and connected collectors.

At the top you get summary figures, and below them:

  • Services — each core service with a Healthy / Degraded / Unknown badge. A green dot means it’s fine; red means it needs attention.
  • Connected collectors — every collector currently connected, with how long it’s been up. If a collector you expect is missing here, it isn’t connected.
  • Trend charts — recent history for key measures (memory, response time, event rate, and connected collectors) so you can see whether something is trending the wrong way rather than just its value right now.

Use Service Management as your daily glance, and drill into an individual collector under Configure → Collectors when something there looks off.

What healthy looks like

Section titled “What healthy looks like”
  • Every expected collector shows Online.
  • Plugin pills are green (or grey for features you’re not using) — none red.
  • Metric bars are well below their limits (green, not amber or red).
  • The collector’s Channels show recent activity with no climbing buffer and no drops (see Collector Channels).
  • No stale metrics warnings.

First steps when something’s wrong

Section titled “First steps when something’s wrong”

A collector is Offline

Section titled “A collector is Offline”
  1. Confirm the collector process is actually running where you deployed it.
  2. Check its network path to GridNMS — the collector makes an outbound connection, so a firewall or proxy change can cut it off.
  3. Once connectivity returns, the collector reconnects on its own — you don’t need to re-register it.
  4. Check last seen on the Collectors list to gauge how long it’s been gone.

A channel is backed up

Section titled “A channel is backed up”
  1. Open the collector’s Channels tab and watch the logging channel buffer depth.
  2. If the buffer drains back toward zero, it was a temporary traffic burst — nothing to do.
  3. If it keeps climbing or you see drops, the collector is receiving more than it can ship. The collector may be undersized for its log volume, or its connection to GridNMS may be constrained.
  4. See Collector Channels for what each channel statistic means.

A plugin pill is red (Crashed)

Section titled “A plugin pill is red (Crashed)”
  1. Give it a moment — crashed workers usually restart automatically.
  2. If it stays red, the collector is likely under stress or hitting a limit. Check its metric bars on the Health tab.
  3. If it persists, see Troubleshooting.
Section titled “Related pages”