First kubectl Session: Inspecting a Cluster

Foundations / Guide 2 of 103 / Beginner

• Kubernetes1.36.4
• Cluster4 nodes
• Runtimecontainerd 2.2.6
• CNICalico v3.32.1
• TimeAbout 20 min

Counts like 27 API groups and 26 running Pods are this cluster's, not universal. The commands that produce them are.

This guide includes

Use this the first time you are handed a cluster and have to work out what it is. This matters because the alternative is guessing at resource names and field paths, and six commands replace all of that guessing.

• confirming which cluster you are pointed at before running anything destructive
• reading client and server versions separately, because they are two different things
• listing what this cluster can actually be asked for with kubectl api-resources
• using kubectl explain --recursive as the field reference you already have, offline
• shaping output with -o wide and custom-columns instead of reading tables by eye

Before you start

• A cluster you can reach and a working kubectl. Any of the installation guides gets you one.
• Nothing else. This guide reads; it does not create anything.

1. 1

   Which cluster am I actually talking to?

2. 2

   Client and server version, separately

3. 3

   What can this cluster even be asked for?

4. 4

   The API groups, and why there are so many

5. 5

   kubectl explain, the field reference you already have

6. 6

   Shape the output instead of reading it

Official sources

• kubectl overview
• kubectl cheat sheet
• Kubernetes API concepts
• API groups and versioning
• JSONPath support
• Version skew policy