Kubectl is the command line to work with a Kubernetes cluster.
It has commands to deploy applications and work with objects in the cluster.
Two of the most common Kubectl commands are get and describe.
You can use them with different objects; try finding information about the nodes in your cluster:
kubectl get nodes
Nodes are the servers in the cluster. The
getcommand prints a table with basic information.
kubectl describe nodes
There's a lot more information to see and
describegives it to you in a readable format.
Kubectl has built-in help, you can use it to list all commands or list the details of one command:
kubectl --help
kubectl get --help
And you can learn about resources by asking Kubectl to explain them:
kubectl explain node
You will spend a lot of time with Kubectl. You'll want to get familiar with some features early on, like querying.
Kubectl can print information in different formats, try showing your node details in JSON:
kubectl get node <your-node> -o json
Check the help to see what other output formats you can use.
One is JSON Path, which is a query language you can use to print specific fields:
kubectl get node <your-node> -o jsonpath='{.status.capacity.cpu}'
This tells you the number of CPU cores Kubernetes sees for that node.
What happens if you try the same command without specifying a node name?
Every object in Kubernetes can have labels - they are key-value pairs used to record additional information about the object.
Nodes have a set of labels which are provisioned by the environment, including some standard ones which all Kubernetes platforms provide.
Use Kubectl to find labels for your node, which will show you (among other things) the CPU architecture and operating system it's using.