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πŸ–₯️ Cluster

Definition​

Kubernetes glossary

A set of worker machines, called nodes, that run containerized applications.

  • Reading: a set of computing machines connected for the same purpose.

Understanding​

  • On this site, a cluster mostly means a Kubernetes cluster.
  • If one command can use several machines at once, I call it a cluster.
  • My home cluster is so short on resources that I accept a single control plane.

Usage​

  • I run a home cluster on four Raspberry Pi boards: two Pi 4 (one is the control plane) and two Pi 5, on MicroK8s. The setup is documented in jyje/cluster.
  • At first all four nodes were workers and three of them were also control plane. Resources ran out, so I now run a single control plane.
  • The nodes first joined over Wi-Fi, but health checks were too slow to manage, so everything is wired now.
  • Frontier models have become very capable, so the cluster now centers on workloads that deploy container-based agent harnesses. I connect a Codex subscription and use them for personal purposes.

Details​

Examples​

  • Ten computers on the same network: one command can use all ten.
  • Five virtual machines inside one computer: one command can use all five.
  • Three virtual machines on each of two computers: every virtual machine can talk to the others, and one command can use them all.
  • A Raspberry Pi on the home router, a recent laptop and an old desktop: if one command can use all of them, it is a cluster.
  • A Kubernetes cluster of four computers at work: the computers form one group and run containers to solve a problem.

References​