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Brief introduction of Kubectl

Before learning how to use kubectl more effectively, you should have a basic understanding of what it is and how it works.

From the user's point of view:

Kubectl is the cockpit that controls Kubernetes. It allows you to perform all possible Kubernetes operations.

From a technical standpoint:

Kubectl is the client of Kubernetes API, through which we have full control of Kubernetes, which means that each Kubernetes operation is exposed as an API port and can be performed through an HTTP request to this endpoint.

Command Daquan (as far as I know) query command

View all pod

Kubectl get pods

Dynamic monitoring to view all pod

Kubectl get pods-w

View all deploymen

Kubectl get deployment

View all service services

Kubectl get service

View associated backend nodes

Kubectl get endpoints

View the log of the relevant POD

Kubectl get logs NAME

Pod copy quantity adjustment

Kubectl scale [--current-replicas=replicas]-- replicas=replicas NAME

Among them

Current number of copies of "--current-replicas"

Number of copies of "--replicas"

The life cycle of the project

Create-- "publish--" update-- "rollback--" delete

Create

Kubect run NAME-- image=image [--port=port] [--replicas=replicas] [--command]

"--image" specifies the image

"--replicas" specifies the number of copies

"--port" specifies the intercom port

Example: kubectl run nginx-- image=nginx:latest-- replicas=3

Use the latest version of nginx as a mirror to create a pods with three copies

Publish

Kubectl expose (- f FILENAME | TYPE NAME) [--port=port] [--protocol=TCP | UDP | SCTP] [--target-port=number-or-name] [--name=name] [--external-ip=external-ip-of-service] [--type=type]

"- f FILENAME" specifies the YAML file name

"TYPE NAME" specifies the deploymen name

"--type" specifies the service type (default is cluster address-clusterip)

Port for internal communication of "--port=80"

"--target-port=80" exposed to external ports

Example: kubectl expose deploy/nginx-- port=80-- target-port=80-- name=nginx-svc-- type=NodePort

Publish nginx as internal port 80, exposed port 80, specified name as nginx-svc, type as node.

Update

New version of kubectl set image deploy/NAME NAME=

Example: kubectl set image deploy/nginx nginx=nginx:1.14

Change nginx version to nginx1.14

Roll back

Kubectl rollout [commands]

Common command:

History displays rollout history

The resource provided by the pause tag is aborted

Resume continues a stopped resource

Status displays the status of rollout

Undo undoes the last rollout

Example: kubectl rollout undo deploy/nginx

Delete

Kubectl delete ([- f FILENAME] | TYPE [(NAME |-l label |-- all)]) [options]

Example:

Kubectl delete svc/nginx-svc

Kubectl delete deploy/nginx

In addition, there are a number of orders.

View resource object abbreviations

Kubectl api-resources

View specific resource details

Kubectl describe (- f FILENAME | TYPE [NAME_PREFIX |-l label] | TYPE/NAME) [options]

Example:

Kubectl describe pod/nginx-7697996758-9d6tf

Kubectl describe svc/nginx

Edit resource details

Kubectl edit (- f FILENAME | TYPE [NAME_PREFIX |-l label] | TYPE/NAME) [options]

Example:

Kubectl edit deploy/NAME

Enter the corresponding pod *

Kubectl exec POD [- c CONTAINER]-- COMMAND [args...] [options]

Example: kubectl exec-it nginx-7697996758-9d6tf bash

View the generated YAML format file

Kubectl run nginx-deployment-image=nginx-port=80-replicas=3-dry-run-o yaml

View the generated JSON format file

Kubectl run nginx-deployment-image=nginx-port=80-replicas=3-dry-run-o json

Generate YAML and JSON file export

Kubectl run nginx-deployment-image=nginx-port=80-replicas=3-dry-run-o json (yaml) > test.json (yaml)

Export existing resources

Kubectl get svc/nginx-svc-- export-o yaml > nginx-svc.yaml

Test the correctness of the command and do not execute it (similar to sh-n in shell script)

Kubectl run nginx-image=nginx-port=80-replicas=2-dry-run

Similarities and differences between create and apply

Create from a YAML file

Kubectl create-f FILENAME [options]

Example: kubectl create-f nginx.yaml

Upgrade deployment from a YAML file

Kubectl apply-f FILENAME

Similarities and differences if the deployment value in the yaml file is deployment, then both of the above commands can create a deployment and generate a corresponding number of podcreate commands: delete all existing things first and generate new ones based on the yaml file. So the configuration in the yaml file must be a complete apply command: upgrade the existing one according to what is listed in the configuration file. So the contents of the yaml file can only write the attributes that need to be upgraded.

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