Kubectl-Commands-05

Kubectl Commands

General Information

• kubectl can be replaced with k by using an alias.
• kubectl makes calls to the kube-apiserver behind the scenes.

Get or List Resources

• List all K8s objects:
  k get all

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  k get all

• List nodes:
  k get nodes

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  k get nodes

• List pods:
  k get pods

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  k get pods

• List pods with additional info:
  k get pods -o wide

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  k get pods -o wide

• List services:
  k get services

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  k get services

  or
  k get svc

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  k get svc

• List deployments:
  k get deployments

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  k get deployments

• List replica sets:
  k get replicasets

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  k get replicasets

• List replica sets with additional information:
  k get replicasets -o wide

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  k get replicasets -o wide

• List deployments in another namespace:
  k get deployments --namespace=<namespace>

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  k get deployments --namespace=<namespace>

• List pods in all namespaces:
  k get pods --all-namespaces

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  k get pods --all-namespaces

• List service accounts:
  k get serviceaccount

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  k get serviceaccount

• List pods with a label filter:
  k get pod --selector key=value

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  k get pod --selector key=value

• Get pods with multiple label filters:
  k get pods --selector env=prod,bu=finance,tier=frontend

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  k get pods --selector env=prod,bu=finance,tier=frontend

• List all jobs:
  k get jobs

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  k get jobs

• List all cron jobs:
  k get cronjobs

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  k get cronjobs

• List all network policies:
  k get networkpolicies

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  k get networkpolicies

• List all ingress resources:
  k get ingress

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  k get ingress

• List persistent volumes:
  k get persistentvolume

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  k get persistentvolume

• List persistent volume claims:
  k get persistentvolumeclaim

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  k get persistentvolumeclaim

• List all DaemonSets:
  k get daemonsets

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  k get daemonsets

• List cluster events:
  k get events -o wide

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  k get events -o wide

• Get which node each pod is deployed on:
  k get pods -o wide

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  k get pods -o wide

Describe Resources

• Describe a pod:
  k describe pod <pod-name>

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  k describe pod <pod-name>

• Describe a deployment:
  k describe deployment <deployment-name>

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  k describe deployment <deployment-name>

• Describe a service account:
  k describe serviceaccount <service-account-name>

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  k describe serviceaccount <service-account-name>

• Describe an ingress:
  k describe ingress <ingress-name>

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  k describe ingress <ingress-name>

• Describe a DaemonSet:
  k describe daemonset <daemonset-name>

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  k describe daemonset <daemonset-name>

Create Resources

• Create a pod from an image:
  k run <pod-name> --image <image-name>

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  k run <pod-name> --image <image-name>

• Apply a K8s config.yaml file (declarative):
  k apply -f <filename>.yaml

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  k apply -f <filename>.yaml

• Create a namespace:
  k create namespace <namespace>

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  k create namespace <namespace>

• Create a service account:
  k create serviceaccount <service-account-name>

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  k create serviceaccount <service-account-name>

Delete Resources

• Delete a pod:
  k delete pod <pod-name>

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  k delete pod <pod-name>

• Delete a replica set:
  k delete replicaset <replicaset-name>

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  k delete replicaset <replicaset-name>

• Delete a deployment:
  k delete deployment <deployment-name>

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  k delete deployment <deployment-name>

• Delete a K8s resource from a config file:
  k delete -f config.yaml

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  k delete -f config.yaml

View Logs

• View logs of a pod:
  k logs <pod-name>

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  k logs <pod-name>

• View live logs of a pod:
  k logs -f <pod-name>

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  k logs -f <pod-name>

• View logs of a container in a multi-container pod:
  k logs <pod-name> <container-name>

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  k logs <pod-name> <container-name>

• View logs of the previous container if the pod failed:
  k logs <pod-name> --previous

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  k logs <pod-name> --previous

Rollouts and Updates

• View the status of rollout for a deployment:
  k rollout status deployment/<deployment-name>

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  k rollout status deployment/<deployment-name>

• View the history of rollouts for a deployment:
  k rollout history deployment/<deployment-name>

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  k rollout history deployment/<deployment-name>

• View the history of a specific rollout revision:
  k rollout history deployment/<deployment-name> --revision=1

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  k rollout history deployment/<deployment-name> --revision=1

• Rollback a deployment:
  k rollout undo deployment/<deployment-name>

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  k rollout undo deployment/<deployment-name>

• Rollback a deployment to a specific revision:
  k rollout undo deployment/<deployment-name> --to-revision=1

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  k rollout undo deployment/<deployment-name> --to-revision=1

Node Commands

• Cordon a node (mark it unschedulable):
  k cordon <node-name>

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  k cordon <node-name>

• Un-cordon a node (mark it schedulable):
  k uncordon <node-name>

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  k uncordon <node-name>

• Drain a node of all the pods:
  k drain <node-name>

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  k drain <node-name>

• Drain a node of all the pods except DaemonSets:
  k drain <node-name> --ignore-daemonsets

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  k drain <node-name> --ignore-daemonsets

Auth Commands

• View roles:
  k get roles

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  k get roles

• View role bindings:
  k get rolebindings

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  k get rolebindings

• Check if you have access to perform an operation:
• Create deployments:
  k auth can-i create deployments

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  k auth can-i create deployments

• Delete nodes in dev namespace:
  k auth can-i delete nodes -n dev

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  k auth can-i delete nodes -n dev

• Check if another user has access to perform an operation:
• Create deployments:
  k auth can-i create deployments --as dev-user

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  k auth can-i create deployments --as dev-user

• Delete nodes in dev namespace:
  k auth can-i delete nodes --as dev-user -n dev

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  k auth can-i delete nodes --as dev-user -n dev

• Check if a service account has access to perform an operation:
  k auth can-i get pods --as=system:serviceaccount:default:<serviceaccount-name>

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  k auth can-i get pods --as=system:serviceaccount:default:<serviceaccount-name>

Config Commands

• List all clusters:
  k config get-clusters

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  k config get-clusters

• Set context for a cluster:
  k config use-context <cluster-name>

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  k config use-context <cluster-name>

Certificates Commands

• List all CSRs:
  k get csr

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  k get csr

• View a CSR in YAML format:
  k get csr <csr-name> -o yaml

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  k get csr <csr-name> -o yaml

• Delete a CSR:
  k delete csr <csr-name>

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  k delete csr <csr-name>

• Approve a CSR:
  k certificate approve <csr-name>

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  k certificate approve <csr-name>

• Deny a CSR:
  k certificate deny <csr-name>

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  k certificate deny <csr-name>

Output Formats

• -o json

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  -o json

  – JSON output
• -o name

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  -o name

  – Only the resource name
• -o wide

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  -o wide

  – Extra info in plain text
• -o yaml

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  -o yaml

  – YAML output

Useful Imperative Commands

• Create a pod:
  k run <pod-name> --image=<image-name> --command -- <command-with-args>

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  k run <pod-name> --image=<image-name> --command -- <command-with-args>

• Create a deployment:
  k create deployment <deployment-name> --image <image-name> --replicas 3

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  k create deployment <deployment-name> --image <image-name> --replicas 3

• Create a service for a deployment:
  k expose deployment <deployment-name> --port 80 --name <service-name>

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  k expose deployment <deployment-name> --port 80 --name <service-name>

• Create a service for a pod:
  k expose pod <pod-name> --port 80 --name <service-name>

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  k expose pod <pod-name> --port 80 --name <service-name>

• Edit a deployment (in memory):
  k edit deployment <deployment-name>

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  k edit deployment <deployment-name>

• Scale a deployment:
  k scale deployment <deployment-name> --replicas 3

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  k scale deployment <deployment-name> --replicas 3

• Update the image in a deployment:
  k set image deployment <deployment-name> <old-image>=<new-image>

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  k set image deployment <deployment-name> <old-image>=<new-image>

• Create resources from a config file:
  k create -f filename.yaml

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  k create -f filename.yaml

• Update resources from a config file:
  k replace -f filename.yaml

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  k replace -f filename.yaml

• Delete and recreate resources from a config file:
  k replace --force -f filename.yaml

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  k replace --force -f filename.yaml

• Edit a deployment (doesn’t work for pods as they require recreation):
  k edit deployment <deployment-name>

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  k edit deployment <deployment-name>

Handy Commands

• Get the config YAML of a pod:
  k get pod <pod-name> -o yaml > pod.yaml

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  k get pod <pod-name> -o yaml > pod.yaml

• Get the config YAML of a deployment:
  k get deployment <deployment-name> -o yaml > deployment.yaml

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  k get deployment <deployment-name> -o yaml > deployment.yaml

• Create a sample config YAML file for a pod:
  k run <pod-name> --image <image-name> --dry-run=client -o yaml > filename.yaml

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  k run <pod-name> --image <image-name> --dry-run=client -o yaml > filename.yaml

• Create a sample config YAML file for a deployment:
  k create deployment <deployment-name> --image <image-name> --dry-run=client -o yaml > filename.yaml

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  k create deployment <deployment-name> --image <image-name> --dry-run=client -o yaml > filename.yaml

• Create a sample config YAML file for a service:
  k expose deployment <deployment-name> --port 80 --dry-run=client -o yaml > filename.yaml

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  k expose deployment <deployment-name> --port 80 --dry-run=client -o yaml > filename.yaml

JSON Path in Kubectl

• Get images of all the pods:
  k get pods -o jsonpath='{.items[0].spec.containers[0].image}'

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  k get pods -o jsonpath='{.items[0].spec.containers[0].image}'

Metrics Commands

• Get top nodes by memory:
  k top nodes --sort-by memory

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  k top nodes --sort-by memory

• Get top nodes by CPU for a context:
  k --context <context> top nodes --sort-by cpu

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  k --context <context> top nodes --sort-by cpu