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GridNMS Docs

What Is a Collector?

A collector is a small, lightweight agent you run inside your network. It’s how GridNMS actually sees your equipment. Every GridNMS deployment — cloud or self-hosted — uses at least one.

What a collector does

Section titled “What a collector does”
  • Checks reachability — pings your devices to track up/down status.
  • Polls for metrics — gathers interface traffic, CPU, memory, disk, and more from your devices using the credentials you provide.
  • Receives logs and traps — listens for syslog and SNMP traps sent by your devices.
  • Runs discovery scans — finds new devices on the ranges you assign.

It then sends all of this back to GridNMS over a single secure outbound connection.

Why outbound-only matters

Section titled “Why outbound-only matters”

You never have to open inbound firewall ports to GridNMS. The collector always makes the connection out to your GridNMS instance, which is simpler and safer — especially across sites and through NAT.

   Your site                              GridNMS
 ┌─────────────────────┐               ┌──────────────┐
 │ switches / routers  │               │              │
 │ firewalls / servers │──► collector ─┼──► web app   │
 │ syslog + SNMP traps │   outbound,   │   dashboards │
 └─────────────────────┘   encrypted   └──────────────┘

How many collectors do I need?

Section titled “How many collectors do I need?”

Run one collector per site or network segment. A single collector can watch many devices across the networks you assign to it, so a small office needs just one. Add more for:

  • Additional physical sites — one collector per location.
  • Isolated network segments — when a single collector can’t route to every subnet.
  • Scale and resilience — spread load across several collectors.
Your setup Collectors
One office 1
Headquarters + 3 branches 4 (one each)
Self-hosted, single site The built-in collector that ships with the stack
Self-hosted, multi-site The built-in one + one per remote site

What a collector is allowed to reach

Section titled “What a collector is allowed to reach”

A collector only talks to the networks you assign to it (plus your GridNMS instance). This assignment is the boundary that controls what it can scan and monitor — see Networks & Sites.

Keeping collectors updated

Section titled “Keeping collectors updated”

Collectors update themselves automatically over their existing connection to GridNMS. There’s nothing to patch by hand.

Next steps

Section titled “Next steps”