apps-on-azure

Examining Nodes with Kubectl

Kubectl is the command line to work with a Kubernetes cluster.

It has commands to deploy applications and work with objects in the cluster.

Working with Nodes

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 get command prints a table with basic information.

kubectl describe nodes

There’s a lot more information to see and describe gives it to you in a readable format.

Getting help

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

Querying and formatting

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?

Lab

Every object in Kubernetes can have labels - they are key-value pairs used to record additional information about the object.

Use Kubectl to find labels for you node, which will confirm the CPU architecture and operating system it’s using.

Stuck? Try hints or check the solution.