Hardware requirements

Sensu backend requirements

Backend minimum requirements

This configuration is the minimum required to run the Sensu backend (although it is insufficient for production use):

  • 64-bit Intel or AMD CPU
  • 4 GB RAM
  • 4 GB free disk space
  • 10 mbps network link

See the Backend recommended configuration for production recommendations.

This configuration is recommended as a baseline for production use to ensure a good user and operator experience:

  • 64 bit four-core Intel or AMD CPU
  • 8 GB RAM
  • SSD (NVMe or SATA3)
  • Gigabit ethernet

Using additional resources (and even over-provisioning) further improves stability and scalability.

The Sensu backend is typically CPU- and storage-intensive. In general, the backend’s use of these resources scales linearly with the total number of checks executed by all Sensu agents connecting to the backend.

The Sensu backend is a massively parallel application that can scale to any number of CPU cores. Provision roughly one CPU core for every 50 checks per second (including agent keepalives). Most installations are fine with four CPU cores, but larger installations may find that more CPU cores (8+) are necessary.

Every executed Sensu check results in storage writes. When provisioning storage, a good guideline is to have twice as many sustained disk input/output operations per second (IOPS) as you expect to have events per second.

Don’t forget to include agent keepalives in this calculation. Each agent publishes a keepalive every 20 seconds. For example, in a cluster of 100 agents, you can expect the agents to consume 10 write IOPS for keepalives.

The Sensu backend uses a relatively modest amount of RAM under most circumstances. Larger production deployments use more RAM (8+ GB).

Sensu agent requirements

Agent minimum requirements

This configuration is the minimum required to run the Sensu agent (although it is insufficient for production use:

  • 386, amd64, ARM (ARMv5 minimum), or MIPS CPU
  • 128 MB RAM
  • 10 mbps network link

See the Agent recommended configuration for production recommendations.

This configuration is recommended as a baseline for production use to ensure a good user and operator experience:

  • 64 bit four-core Intel or AMD CPU
  • 512 MB RAM
  • Gigabit ethernet

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

Networking recommendations

Agent connections

Sensu uses WebSockets for communication between the agent and backend. All communication occurs over a single TCP socket.

We recommend that you connect backends and agents via gigabit ethernet, but any reliable network link should work (for example, WiFi and 4G). If you see WebSocket timeouts in the backend logs, you may need to use a more reliable network link between the backend and agents.

Cloud recommendations

AWS

The recommended EC2 instance type and size for Sensu backends running embedded etcd is M5d.xlarge. The M5d instance provides four vCPU, 16 GB of RAM, up to 10 gbps network connectivity, and a 150-NVMe SSD directly attached to the instance host (optimal for sustained disk IOPS).