Add prometheus demo

content/Articles/kubectl-essential.en.md

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+---
+title: 'Essential kubectl Commands'
+date: 2024-06-11T14:15:26+10:00
+draft: false
+weight: 1
+tags: ["kubernetes", "kubectl"]
+---
+
+**Duration:** 5 min read
+
+## List a Resource from the API Server
+To retrieve details of a specific resource in Kubernetes, use the following command:
+
+```sh
+kubectl get <resource-name> <obj-name> [-o yaml/json]
+```
+
+## Describe a Resource from the API Server
+To get a detailed description of a specific resource, use:
+
+```sh
+kubectl describe <resource-name> <obj-name>
+```
+
+## Create or Update Resources from a File
+To create or update resources from a YAML file, use:
+
+```sh
+kubectl apply -f obj.yaml
+```
+
+## Delete Resources from a File
+To delete resources defined in a YAML file, use:
+
+```sh
+kubectl delete -f obj.yaml
+# or to destroy the resource by its name
+kubectl delete <resource-name> <obj-name>
+```
+
+## Edit a Resource in the Kubernetes Database (i.e., etcd)
+To edit a resource directly in the Kubernetes database, use:
+
+```sh
+kubectl edit <resource-name> <obj-name>
+```
+> [Learn more about best practices for microservices](https://12factor.net/codebase)
+
+## Display Inline Documentation (and Provide Useful Examples)
+To display help and usage examples for a specific command, use:
+
+```sh
+kubectl create job --help
+# or
+kubectl help create job
+```
+
+## Describe YAML Specification
+To get a description of the YAML specification for a specific resource type, use:
+
+```sh
+kubectl explain pods.spec [--recursive]
+```
+
+## Display Logs for a Container (i.e., stdout/stderr)
+To display logs from a specific container, use:
+
+```sh
+kubectl logs <pod-name> [ -c <container-name> ]
+```
+> [Learn more about log management](https://12factor.net/logs)
+
+## Open an Interactive Shell Inside a Container
+To open an interactive shell inside a container, use:
+
+```sh
+kubectl exec -it <pod-name> -- bash
+```
+
+## Provide Network Access to a Pod
+To listen on port 8080 locally and forward data to/from port 80 in the pod, use:
+
+```sh
+# Listen on port 8080 locally, forwarding data to/from port 80 in the pod
+kubectl port-forward pod/mypod 8080:80 &
+
+# Access the pod with an HTTP client
+curl http://localhost:8080
+```
+
+## Quickly Generate a YAML Specification
+
+The `--dry-run=client -o yaml` options allow you to generate YAML without creating the resource in Kubernetes. They are very useful for quickly generating YAML files that can serve as a working base. Here is an example of its usage:
+
+```sh
+kubectl create service clusterip my-service --tcp=5678:8080 --dry-run=client -o yaml
+```
+
+## See List of Resources in Use
+
+This command requires the installation of 'kubernetes-sigs/metrics-server'. To display metrics for nodes and pods, use:
+
+```sh
+kubectl top nodes
+kubectl top pods
+```
+
+## Copy Files To and From a Container
+To copy files to and from a container, use:
+
+```sh
+kubectl cp <pod-name:/path/to/remote/file> </path/to/local/file>
+```