### KUBECTL - CHEAT SHEET ###


## KUBECTL AUTOCOMPLETE  ##

BASH
source <(kubectl completion bash) # setup autocomplete in bash into the current shell, bash-completion package should be installed first.
echo "source <(kubectl completion bash)" >> ~/.bashrc # add autocomplete permanently to your bash shell.









## KUBECTL CONTEXT AND CONFIGURATION ##

Set which Kubernetes cluster kubectl communicates with and modifies configuration information. See Authenticating Across Clusters with kubeconfig documentation for detailed config file information.

kubectl config view # Show Merged kubeconfig settings.

# use multiple kubeconfig files at the same time and view merged config
KUBECONFIG=~/.kube/config:~/.kube/kubconfig2 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}'    # 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

# add a new cluster to your kubeconf that supports basic auth
kubectl config set-credentials kubeuser/foo.kubernetes.com --username=kubeuser --password=kubepassword

# permanently save the namespace for all subsequent kubectl commands in that context.
kubectl config set-context --current --namespace=ggckad-s2

# set a context utilizing a specific username and namespace.
kubectl config set-context gce --user=cluster-admin --namespace=foo \
  && kubectl config use-context gce
 
kubectl config unset users.foo                       # delete user foo









## APPLY ##

apply manages applications through files defining Kubernetes resources. It creates and updates resources in a cluster through running kubectl apply. This is the recommended way of managing Kubernetes applications on production. See Kubectl Book.

Creating Objects
Kubernetes manifests can be defined in json or yaml. The file extension .yaml, .yml, and .json can be used.

kubectl apply -f ./my-manifest.yaml           # create resource(s)
kubectl apply -f ./my1.yaml -f ./my2.yaml     # create from multiple files
kubectl apply -f ./dir                        # create resource(s) in all manifest files in dir
kubectl apply -f https://git.io/vPieo         # create resource(s) from url
kubectl create deployment nginx --image=nginx  # start a single instance of nginx
kubectl explain pods,svc                       # get the documentation for pod and svc manifests

# Create multiple YAML objects from stdin
cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: Pod
metadata:
  name: busybox-sleep
spec:
  containers:
  - name: busybox
    image: busybox
    args:
    - sleep
    - "1000000"
---
apiVersion: v1
kind: Pod
metadata:
  name: busybox-sleep-less
spec:
  containers:
  - name: busybox
    image: busybox
    args:
    - sleep
    - "1000"
EOF

# 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









## VIEWING, FINDINGRESOURCES ##

# Get commands with basic output
kubectl get services                          # List all services in the namespace
kubectl get pods --all-namespaces             # List all pods in all namespaces
kubectl get pods -o wide                      # List all pods in the namespace, with more details
kubectl get deployment my-dep                 # List a particular deployment
kubectl get pods --include-uninitialized      # List all pods in the namespace, including uninitialized ones
kubectl get pod my-pod -o yaml                # Get a pod's YAML
kubectl get pod my-pod -o yaml --export       # Get a pod's YAML without cluster specific information

# Describe commands with verbose output
kubectl describe nodes my-node
kubectl describe pods my-pod

kubectl get services --sort-by=.metadata.name # List Services Sorted by Name

# List pods Sorted by Restart Count
kubectl get pods --sort-by='.status.containerStatuses[0].restartCount'

# Get the version label of all pods with label app=cassandra
kubectl get pods --selector=app=cassandra rc -o \
  jsonpath='{.items[*].metadata.labels.version}'

# 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 all running pods in the namespace
kubectl get pods --field-selector=status.phase=Running

# Get ExternalIPs of all nodes
kubectl get nodes -o jsonpath='{.items[*].status.addresses[?(@.type=="ExternalIP")].address}'

# List Names of Pods that belong to Particular RC
# "jq" command useful for transformations that are too complex for jsonpath, it can be found at https://stedolan.github.io/jq/
sel=${$(kubectl get rc my-rc --output=json | jq -j '.spec.selector | to_entries | .[] | "\(.key)=\(.value),"')%?}
echo $(kubectl get pods --selector=$sel --output=jsonpath={.items..metadata.name})

# Show labels for all pods (or any other Kubernetes object that supports labelling)
# Also uses "jq"
for item in $( kubectl get pod --output=name); do printf "Labels for %s\n" "$item" | grep --color -E '[^/]+$' && kubectl get "$item" --output=json | jq -r -S '.metadata.labels | to_entries | .[] | " \(.key)=\(.value)"' 2>/dev/null; printf "\n"; done

# Check which nodes are ready
JSONPATH='{range .items[*]}{@.metadata.name}:{range @.status.conditions[*]}{@.type}={@.status};{end}{end}' \
 && kubectl get nodes -o jsonpath="$JSONPATH" | grep "Ready=True"

# List all Secrets currently in use by a pod
kubectl get pods -o json | jq '.items[].spec.containers[].env[]?.valueFrom.secretKeyRef.name' | grep -v null | sort | uniq

# List Events sorted by timestamp
kubectl get events --sort-by=.metadata.creationTimestamp









## UPDATING RESOURCES ##

As of version 1.11 rolling-update have been deprecated (see CHANGELOG-1.11.md), use rollout instead.

kubectl set image deployment/frontend www=image:v2               # Rolling update "www" containers of "frontend" deployment, updating the image
kubectl rollout undo deployment/frontend                         # Rollback to the previous deployment
kubectl rollout status -w deployment/frontend                    # Watch rolling update status of "frontend" deployment until completion

# deprecated starting version 1.11
kubectl rolling-update frontend-v1 -f frontend-v2.json           # (deprecated) Rolling update pods of frontend-v1
kubectl rolling-update frontend-v1 frontend-v2 --image=image:v2  # (deprecated) Change the name of the resource and update the image
kubectl rolling-update frontend --image=image:v2                 # (deprecated) Update the pods image of frontend
kubectl rolling-update frontend-v1 frontend-v2 --rollback        # (deprecated) Abort existing rollout in progress

cat pod.json | kubectl replace -f -                              # Replace a pod based on the JSON passed into std

# Force replace, delete and then re-create the resource. Will cause a service outage.
kubectl replace --force -f ./pod.json

# Create a service for a replicated nginx, which serves on port 80 and connects to the containers on port 8000
kubectl expose rc nginx --port=80 --target-port=8000

# Update a single-container pod's image version (tag) to v4
kubectl get pod mypod -o yaml | sed 's/\(image: myimage\):.*$/\1:v4/' | kubectl replace -f -

kubectl label pods my-pod new-label=awesome                      # Add a Label
kubectl annotate pods my-pod icon-url=http://goo.gl/XXBTWq       # Add an annotation
kubectl autoscale deployment foo --min=2 --max=10                # Auto scale a deployment "foo"









## PATCHING RESOURCES ##

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

# Update a container's image; spec.containers[*].name is required because it's a merge key
kubectl patch pod valid-pod -p '{"spec":{"containers":[{"name":"kubernetes-serve-hostname","image":"new image"}]}}'

# Update a container's image using a json patch with positional arrays
kubectl patch pod valid-pod --type='json' -p='[{"op": "replace", "path": "/spec/containers/0/image", "value":"new image"}]'

# Disable a deployment livenessProbe using a json patch with positional arrays
kubectl patch deployment valid-deployment  --type json   -p='[{"op": "remove", "path": "/spec/template/spec/containers/0/livenessProbe"}]'

# Add a new element to a positional array 
kubectl patch sa default --type='json' -p='[{"op": "add", "path": "/secrets/1", "value": {"name": "whatever" } }]'








## EDITING RESOURCES ##

he edit any API resource in an editor.

kubectl edit svc/docker-registry                      # Edit the service named docker-registry
KUBE_EDITOR="nano" kubectl edit svc/docker-registry   # Use an alternative editor











## SCALING RESOURCES ##

kubectl scale --replicas=3 rs/foo                                 # Scale a replicaset named 'foo' to 3
kubectl scale --replicas=3 -f foo.yaml                            # Scale a resource specified in "foo.yaml" to 3
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












## DELETING RESOURCES ##

kubectl delete -f ./pod.json                                              # Delete a pod using the type and name specified in pod.json
kubectl delete pod,service baz foo                                        # Delete pods and services with same names "baz" and "foo"
kubectl delete pods,services -l name=myLabel                              # Delete pods and services with label name=myLabel
kubectl delete pods,services -l name=myLabel --include-uninitialized      # Delete pods and services, including uninitialized ones, with label name=myLabel
kubectl -n my-ns delete po,svc --all                                      # Delete all pods and services, including uninitialized ones, in namespace my-ns










## INTERACTING WITH RUNNING PODS ##

kubectl logs my-pod                                 # dump pod logs (stdout)
kubectl logs my-pod --previous                      # dump pod logs (stdout) for a previous instantiation of a container
kubectl logs my-pod -c my-container                 # dump pod container logs (stdout, multi-container case)
kubectl logs my-pod -c my-container --previous      # dump pod container logs (stdout, multi-container case) for a previous instantiation of a container
kubectl logs -f my-pod                              # stream pod logs (stdout)
kubectl logs -f my-pod -c my-container              # stream pod container logs (stdout, multi-container case)
kubectl run -i --tty busybox --image=busybox -- sh  # Run pod as interactive shell
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 my-pod -c my-container -- ls /         # Run command in existing pod (multi-container case)
kubectl top pod POD_NAME --containers               # Show metrics for a given pod and its containers









## INTERACTING WITH NODES AND CLUSTERS ##

kubectl cordon my-node                                                # Mark my-node as unschedulable
kubectl drain my-node                                                 # Drain my-node in preparation for maintenance
kubectl uncordon my-node                                              # Mark my-node as schedulable
kubectl top node my-node                                              # Show metrics for a given node
kubectl cluster-info                                                  # Display addresses of the master and services
kubectl cluster-info dump                                             # Dump current cluster state to stdout
kubectl cluster-info dump --output-directory=/path/to/cluster-state   # Dump current cluster state to /path/to/cluster-state

# 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
List all supported resource types along with their shortnames, API group, whether they are namespaced, and Kind:

kubectl api-resources
Other operations for exploring API resources:

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 (just 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