Shulou(Shulou.com)06/02 Report--

As a user of Kubernetes, the most frequently used command every day is kubectl XXX.

Kubectl is actually a console, which mainly provides the following functions:

1. Provide REST API interface for Kubernetes cluster management, including authentication authorization, data verification and cluster status change

two。 Provides a hub for data exchange and communication between other modules (other modules query or modify data through API Server, and only API Server directly manipulates etcd)

In other words, every kubectl command we enter in the terminal is actually a Restful API call to Kubernetes API server.

We can do an experiment:

Kubectl get secret-vault 9, which sets the highest level of trace through-vault 9:

Observe from the output that the call to API server to retrieve all the secret url: https://xxxx/api/v1/namespaces/ / secrets?limit=500:

The format of this HTTP request can be found on the Kubernetes website.

So how does the kubectl command know which API server to send the request to?

Run the command kubectl config view to display the server in the content: the address that follows is the url of API server.

The content displayed by kubectl config view comes from the configuration file: ~ / .kube/config:

In fact, Kubernetes's kubectl works the same way as CloudFoundry's command-line tool cf.

Set the operating system environment variable CF_TRACE = true

Then execute any cf command, and you can see that these commands are actually sending a HTTP request to an endpoint in SAP Cloud Platform.

Example: cf logs connectvity-demo-approuter-- recent

You can then see the payload of the HTTP requests and responses sent to complete this command.

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