Heart of Kubernetes: The API Server

Kubernetes API Server is the heart of everything. When you change something from the kubernetes or ICP dashboard you interact with the k8s API server via REST call.

kubectl or bx command line tool interact directly with the API Server, for example:
kubectl get namespaces
NAME          STATUS    AGE
default       Active    1d
kube-system   Active    1d
kube-public   Active    1d
if you run the same command with the -v9 parameter you can get debug information.

as you can see in the image a rest call was made from kubeclt client and in the output you can find the related curl command.

You can do the same via browser by exposing api server temporaly with this command

kubectl proxy --port=8080

and in the browser you will see your namespace in json format

These information are located in the etcd database, in other words k8s API server expose method to read and update etcd database and change the state of the cluster. In this way you can manipulate service, deployment and many other k8s stuff.



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