From 3470091f146efdd11794b39c00c2ab6e5aada4fd Mon Sep 17 00:00:00 2001
From: LearnwithShiv <116908363+LearnwithShiv@users.noreply.github.com>
Date: Sat, 26 Nov 2022 11:02:08 +0530
Subject: [PATCH] Create K8s Commands

---
 Kubernetes/K8s Commands | 309 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 309 insertions(+)
 create mode 100644 Kubernetes/K8s Commands

diff --git a/Kubernetes/K8s Commands b/Kubernetes/K8s Commands
new file mode 100644
index 0000000..202f987
--- /dev/null
+++ b/Kubernetes/K8s Commands	
@@ -0,0 +1,309 @@
+source <(kubectl completion bash) # set up 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 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}'    # 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 set-cluster my-cluster-name           # set a cluster entry in the kubeconfig
+
+# configure the URL to a proxy server to use for requests made by this client in the kubeconfig
+kubectl config set-cluster my-cluster-name --proxy-url=my-proxy-url
+
+# add a new user 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
+
+# short alias to set/show context/namespace (only works for bash and bash-compatible shells, current context to be set before using kn to set namespace) 
+alias kx='f() { [ "$1" ] && kubectl config use-context $1 || kubectl config current-context ; } ; f'
+alias kn='f() { [ "$1" ] && kubectl config set-context --current --namespace $1 || kubectl config view --minify | grep namespace | cut -d" " -f6 ; } ; f'
+
+-----------------------------------Creating objects------------------------------------
+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
+
+# create a Job which prints "Hello World"
+kubectl create job hello --image=busybox:1.28 -- echo "Hello World"
+
+# create a CronJob that prints "Hello World" every minute
+kubectl create cronjob hello --image=busybox:1.28   --schedule="*/1 * * * *" -- echo "Hello World"
+
+kubectl explain pods                           # get the documentation for pod 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:1.28
+    args:
+    - sleep
+    - "1000000"
+---
+apiVersion: v1
+kind: Pod
+metadata:
+  name: busybox-sleep-less
+spec:
+  containers:
+  - name: busybox
+    image: busybox:1.28
+    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 and finding resources---------------------------------------
+Viewing and finding resources
+# 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 current namespace, with more details
+kubectl get deployment my-dep                 # List a particular deployment
+kubectl get pods                              # List all pods in the namespace
+kubectl get pod my-pod -o yaml                # Get a pod's YAML
+
+# Describe commands with verbose output
+kubectl describe nodes my-node
+kubectl describe pods my-pod
+
+# List Services Sorted by Name
+kubectl get services --sort-by=.metadata.name
+
+# List pods Sorted by Restart Count
+kubectl get pods --sort-by='.status.containerStatuses[0].restartCount'
+
+# List PersistentVolumes sorted by capacity
+kubectl get pv --sort-by=.spec.capacity.storage
+
+# Get the version label of all pods with label app=cassandra
+kubectl get pods --selector=app=cassandra -o \
+  jsonpath='{.items[*].metadata.labels.version}'
+
+# Retrieve the value of a key with dots, e.g. 'ca.crt'
+kubectl get configmap myconfig \
+  -o jsonpath='{.data.ca\.crt}'
+
+# Retrieve a base64 encoded value with dashes instead of underscores.
+kubectl get secret my-secret --template='{{index .data "key-name-with-dashes"}}'
+
+# Get all worker nodes (use a selector to exclude results that have a label
+# named 'node-role.kubernetes.io/control-plane')
+kubectl get node --selector='!node-role.kubernetes.io/control-plane'
+
+# 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)
+kubectl get pods --show-labels
+
+# 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"
+
+# Output decoded secrets without external tools
+kubectl get secret my-secret -o go-template='{{range $k,$v := .data}}{{"### "}}{{$k}}{{"\n"}}{{$v|base64decode}}{{"\n\n"}}{{end}}'
+
+# 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 all containerIDs of initContainer of all pods
+# Helpful when cleaning up stopped containers, while avoiding removal of initContainers.
+kubectl get pods --all-namespaces -o jsonpath='{range .items[*].status.initContainerStatuses[*]}{.containerID}{"\n"}{end}' | cut -d/ -f3
+
+# List Events sorted by timestamp
+kubectl get events --sort-by=.metadata.creationTimestamp
+
+# Compares the current state of the cluster against the state that the cluster would be in if the manifest was applied.
+kubectl diff -f ./my-manifest.yaml
+
+# Produce a period-delimited tree of all keys returned for nodes
+# Helpful when locating a key within a complex nested JSON structure
+kubectl get nodes -o json | jq -c 'paths|join(".")'
+
+# Produce a period-delimited tree of all keys returned for pods, etc
+kubectl get pods -o json | jq -c 'paths|join(".")'
+
+# Produce ENV for all pods, assuming you have a default container for the pods, default namespace and the `env` command is supported.
+# Helpful when running any supported command across all pods, not just `env`
+for pod in $(kubectl get po --output=jsonpath={.items..metadata.name}); do echo $pod && kubectl exec -it $pod -- env; done
+
+# Get a deployment's status subresource
+kubectl get deployment nginx-deployment --subresource=status
+
+-------------------------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
+
+
+cat pod.json | kubectl replace -f -                              # Replace a pod based on the JSON passed into stdin
+
+# 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
+# Partially update a node
+kubectl patch node k8s-node-1 -p '{"spec":{"unschedulable":true}}'
+
+# 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" } }]'
+
+# Update a deployment's replica count by patching its scale subresource
+kubectl patch deployment nginx-deployment --subresource='scale' --type='merge' -p '{"spec":{"replicas":2}}'
+
+-----------------------------------Editing resources--------------------------------------
+
+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 unwanted --now                                 # Delete a pod with no grace period
+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 -n my-ns delete pod,svc --all                             # Delete all pods and services in namespace my-ns,
+# Delete all pods matching the awk pattern1 or pattern2
+kubectl get pods  -n mynamespace --no-headers=true | awk '/pattern1|pattern2/{print $1}' | xargs  kubectl delete -n mynamespace pod
+
+
+--------------------------------Interacting with running Pods-----------------------------
+kubectl logs my-pod                                 # dump pod logs (stdout)
+kubectl logs -l name=myLabel                        # dump pod logs, with label name=myLabel (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 -l name=myLabel -c my-container        # dump pod logs, with label name=myLabel (stdout)
+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 logs -f -l name=myLabel --all-containers    # stream all pods logs with label name=myLabel (stdout)
+kubectl run -i --tty busybox --image=busybox:1.28 -- sh  # Run pod as interactive shell
+kubectl run nginx --image=nginx -n mynamespace      # Start a single instance of nginx pod in the namespace of mynamespace
+kubectl run nginx --image=nginx --dry-run=client -o yaml > pod.yaml
+                                                    # Generate spec for running pod nginx and write it into a file called pod.yaml
+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 --stdin --tty my-pod -- /bin/sh        # Interactive shell access to a running 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
+kubectl top pod POD_NAME --sort-by=cpu              # Show metrics for a given pod and sort it by 'cpu' or 'memory'
+
+
+------------------------------Copying files and directories to and from containers---------------------
+kubectl cp /tmp/foo_dir my-pod:/tmp/bar_dir            # Copy /tmp/foo_dir local directory to /tmp/bar_dir in a remote pod in the current namespace
+kubectl cp /tmp/foo my-pod:/tmp/bar -c my-container    # Copy /tmp/foo local file to /tmp/bar in a remote pod in a specific container
+kubectl cp /tmp/foo my-namespace/my-pod:/tmp/bar       # Copy /tmp/foo local file to /tmp/bar in a remote pod in namespace my-namespace
+kubectl cp my-namespace/my-pod:/tmp/foo /tmp/bar       # Copy /tmp/foo from a remote pod to /tmp/bar locally
+
+-----------------------------Interacting with Deployments and Services----------------------------------
+kubectl logs deploy/my-deployment                         # dump Pod logs for a Deployment (single-container case)
+kubectl logs deploy/my-deployment -c my-container         # dump Pod logs for a Deployment (multi-container case)
+
+kubectl port-forward svc/my-service 5000                  # listen on local port 5000 and forward to port 5000 on Service backend
+kubectl port-forward svc/my-service 5000:my-service-port  # listen on local port 5000 and forward to Service target port with name <my-service-port>
+
+kubectl port-forward deploy/my-deployment 5000:6000       # listen on local port 5000 and forward to port 6000 on a Pod created by <my-deployment>
+kubectl exec deploy/my-deployment -- ls                   # run command in first Pod and first container in Deployment (single- or multi-container cases)
+
+--------------------------------Interacting with Nodes and cluster-----------------------------------------
+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
+
+# View existing taints on which exist on current nodes.
+kubectl get nodes -o='custom-columns=NodeName:.metadata.name,TaintKey:.spec.taints[*].key,TaintValue:.spec.taints[*].value,TaintEffect:.spec.taints[*].effect'
+
+# 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 (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