Hardware requirements

Backend minimum requirements

  • 64-bit Intel or AMD CPU
  • 4 GB RAM
  • 4 GB free disk space
  • 10 mbps network link
  • 64 bit 4-core Intel or AMD CPU
  • 8 GB RAM
  • SSD (NVMe or SCSI)
  • Gigabit ethernet

The Sensu backend is typically CPU and storage intensive. Its use of these resources scales linearly with the total number of checks that all agents connecting to the backend are executing.

Sensu backend is a massively parallel application that can scale to any number of CPU cores. Provision roughly 1 CPU core for every 50 checks per second, including keepalives.

Most installations are fine with 4 CPU cores, but larger installations may find that 8 CPU cores are necessary.

Each check that is executed results in writes occurring in the backend. When provisioning storage hardware, a good rule of thumb is to have twice as many iops as you expect to have checks executing per second. Don’t forget to include keepalives in this calculation; each agent executes a keepalive every 20 seconds. So in a cluster of 100 agents, you can expect those agents to consume 10 write iops for keepalives.

The Sensu backend uses a relatively modest amount of RAM under most circumstances, but some users with a large amount of information stored may find that Sensu uses a large amount of RAM (2-4 GB). In many installations, 8 GB is more than sufficient.

Agent minimum requirements

  • 386, amd64, or ARM CPU (armv5 minimum)
  • 128 MB RAM
  • 10 mbps network link
  • 4-core amd64 or ARMv8 CPU
  • 512 MB RAM
  • Gigabit ethernet

The Sensu agent itself is quite lightweight, and should be able to run on all but the most modest hardware. However, since the agent is responsible for executing checks, factor the agent’s responsibilities into your hardware provisioning.

Networking recommendations

Sensu uses websockets for communicating between the backend and the agent. This means that all communication between a backend and an agent occurs over a single TCP socket.

It’s recommended that users connect backends and agents via gigabit ethernet, but any somewhat-reliable network link should work. If you see websocket timeouts in the backend logs from agentd, then you may need to use a better network link between the backend and agents.