| title | notetype | date |
|---|---|---|
K8S Apiserver |
feed |
03-11-2021 |
Kube Apiserver is the primary component of a [[Kubernetes]] cluster. It runs on a [[K8S Master Node]], and is the only component which is talking directly to the [[etcd cluster]]. It exposes a REST API through which all K8S components interact with the cluster / with each other.
Whenever you execute a kubectl command, your client is sending a request to the Kube Apiserver.
If a kubectl GET request is sent, kube apiserver:
- authenticates and validates the request
- retrieves the data from etcd cluster
- responds back with the requested information
Instead of using kubectl it would be possible to invoke the APIs directly. For example, making a POST request to create a pod in the lines of curl -X POST /api/v1/namespaces/default/pods.... will trigger the following actions:
- authenticate user (see [[K8S RBAC]])
- validate request
- update etcd
- inform the user that the [[K8S Pod]] has been created
From here, other components start acting to make sure pod starts running. This process is described in more detail in [[What happens when you create a Pod in Kubernetes]].
Status: #🌲