K8s command summary

debug
refer
refer2

• -v6

  kubectl scale deployment AA --replicas=6 -v 6
  

• config

kubectl config view

# get the password for the e2e user
kubectl config view -o jsonpath='{.users[?(@.name == "e2e")].user.password}'

kubectl config view -o jsonpath='{.users[].name}'    # display the first user
kubectl config view -o jsonpath='{.users[*].name}'   # get a list of users
kubectl config get-contexts                          # display list of contexts 
kubectl config current-context                       # display the current-context
kubectl config use-context my-cluster-name           # set the default context to my-cluster-name
kubectl config unset users.foo                       # delete user foo

• apply

  //oneline
  # Create a secret with several keys
  cat <<EOF | kubectl apply -f -
  apiVersion: v1
  kind: Secret
  metadata:
  name: mysecret
  type: Opaque
  data:
  password: $(echo -n "s33msi4" | base64 -w0)
  username: $(echo -n "jane" | base64 -w0)
  EOF
  

• finding resources

  # List pods Sorted by Restart Count
  kubectl get pods --sort-by='.status.containerStatuses[0].restartCount'
  # Get all worker nodes (use a selector to exclude results that have a label
  # named 'node-role.kubernetes.io/master')
  kubectl get node --selector='!node-role.kubernetes.io/master'
  # Get ExternalIPs of all nodes
  kubectl get nodes -o jsonpath='{.items[*].status.addresses[?(@.type=="ExternalIP")].address}'
  # Get by Age
  kubectl get nodes --sort-by=".metadata.creationTimestamp"
  

• updating resources

  kubectl set image deployment/frontend www=image:v2               # Rolling update "www" containers of "frontend" deployment, updating the image
  kubectl rollout history deployment/frontend                      # Check the history of deployments including the revision 
  kubectl rollout undo deployment/frontend                         # Rollback to the previous deployment
  kubectl rollout undo deployment/frontend --to-revision=2         # Rollback to a specific revision
  kubectl rollout status -w deployment/frontend                    # Watch rolling update status of "frontend" deployment until completion
  kubectl rollout restart deployment/frontend                      # Rolling restart of the "frontend" deployment
  kubectl expose rc nginx --port=80 --target-port=8000
  

• patching resources

  # Partially update a node
  kubectl patch node k8s-node-1 -p '{"spec":{"unschedulable":true}}'
  

• scaling

  kubectl scale --current-replicas=2 --replicas=3 deployment/mysql  # If the deployment named mysql's current size is 2, scale mysql to 3
  kubectl scale --replicas=5 rc/foo rc/bar rc/baz                   # Scale multiple replication controllers
  

• interacting

  kubectl logs -f -l name=myLabel --all-containers    # stream all pods logs with label name=myLabel (stdout)
  kubectl run -i --tty busybox --image=busybox -- sh  # Run pod as interactive shel
  kubectl attach my-pod -i                            # Attach to Running Container
  kubectl port-forward my-pod 5000:6000               # Listen on port 5000 on the local machine and forward to port 6000 on my-pod
  kubectl exec my-pod -- ls /                         # Run command in existing pod (1 container case)
  kubectl exec -it $(kubectl get pod -l app=AA -o name) -- ls /
  kubectl top pod POD_NAME --containers               # Show metrics for a given pod and its containers
  

• with nodes and cluster

  kubectl top node my-node                                              # Show metrics for a given node
  kubectl cluster-info dump                                             # Dump current cluster state to stdout
  # If a taint with that key and effect already exists, its value is replaced as specified.
  kubectl taint nodes foo dedicated=special-user:NoSchedule
  

• resource types

  kubectl api-resources --namespaced=true      # All namespaced resources
  kubectl api-resources --namespaced=false     # All non-namespaced resources
  kubectl api-resources -o name                # All resources with simple output (only the resource name)
  kubectl api-resources -o wide                # All resources with expanded (aka "wide") output
  kubectl api-resources --verbs=list,get       # All resources that support the "list" and "get" request verbs
  kubectl api-resources --api-group=extensions # All resources in the "extensions" API group
  

• log verbosity

   //
   --v=0	Generally useful for this to always be visible to a cluster operator.
   --v=1	A reasonable default log level if you don't want verbosity.
   --v=2	Useful steady state information about the service and important log messages that may correlate to significant changes in the system. This is the recommended default log level for most systems.
   --v=3	Extended information about changes.
   --v=4	Debug level verbosity.
   --v=5	Trace level verbosity.
   --v=6	Display requested resources.
   --v=7	Display HTTP request headers.
   --v=8	Display HTTP request contents.
   --v=9	Display HTTP request contents without truncation of contents.
  

• raw api

  kubectl get --raw /api/v1/nodes/<node>/proxy/stats/summary
  

• kubectl delete pod
  termination lifecycle

• kubectl apply/replace/patch
  article

• kubectl create/apply
  vs

container

 time cat /sys/fs/cgroup/memory/memory.stat >/dev/null

etcd

etcdctl --endpoints 127.0.0.1:2379,127.0.0.1:2380,127.0.0.1:2381 endpoint status --cluster -w table
etcdctl defrag —command-timeout=5m
ETCDCTL_API=3 etcdctl move-leader ${MEMBER_ID} --endpoints http://etcd-0.etcd:2380,http://etcd-1.etcd:2380,http://etcd-2.etcd:2380

iptables

sudo iptables -L KUBE-NODEPORTS -t nat
sudo iptables -L KUBE-MARK-MASQ -t nat

bash alias

kall() { kubectl get pods --all-namespaces -o wide --field-selector spec.nodeName="$1"; }