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kubernetes cheatsheet
## Useful Commands
Get kubectl version
kubectl version
Get cluster info:
kubectl cluster-info
## Viewing, Finding Resources
### Columnar 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 rc <rc-name> # List a particular replication controller
kubectl get pods -l env=production # List all pods with a label env=production
### Verbose output
kubectl describe nodes <node-name>
kubectl describe pods <pod-name>
kubectl describe pods <rc-name> # Lists pods created by <rc-name> using common prefix
### 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
### 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 ExternalIPs of all nodes
kubectl get nodes -o jsonpath='{.items[*].status.addresses[?(@.type=ExternalIP)].address}'
### Check which nodes are ready
kubectl get nodes -o jsonpath='{range .items[*]}{@.metadata.name}:{range @.status.conditions[*]}{@.type}={@.status};{end}{end}'| tr ';' "\n" | grep "Ready=True"
## Creating Objects
kubectl create -f ./file.yml
kubectl create -f ./file1.yml -f ./file2.yaml
kubectl create -f ./dir
kubectl create -f http://www.fpaste.org/279276/48569091/raw/
### Create multiple YAML objects from stdin
cat <<EOF | kubectl create -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 create -f -
apiVersion: v1
kind: Secret
metadata:
name: mysecret
type: Opaque
data:
password: $(echo -n "Sup3rS3cr3t" | base64)
username: $(echo -n "superuser" | base64)
EOF
## Modifying and Deleting Resources
kubectl label pods <pod-name> new-label=awesome # Add a Label
kubectl annotate pods <pod-name> icon-url=http://goo.gl/XXBTWq # Add an annotation
kubectl delete pod pingredis-XXXXX
## Scaling up & down
kubectl scale --replicas=3 deployment nginx
### Interacting with running Pods
kubectl logs <pod-name>
kubectl logs -f <pod-name>
kubectl run -i --tty busybox --image=busybox -- sh # Run pod as interactive shell
kubectl attach <podname> -i # Attach to Running Container
kubectl port-forward <podname> <local-and-remote-port> # Forward port of Pod to your local machine
kubectl port-forward <servicename> <port> # Forward port to service
kubectl exec <pod-name> -- ls / # Run command in existing pod (1 container case)
kubectl exec <pod-name> -c <container-name> -- ls / # Run command in existing pod (multi-container case)
## Checking that the DNS works:
kubectl exec busybox -- nslookup kubernetes
kubectl exec busybox -- nslookup kubernetes.default
kubectl exec busybox -- nslookup kubernetes.default.svc.cluster.local
## Create an expose a deployment
kubectl run nginx --image=nginx:1.9.12
kubectl expose deployment nginx --port=80 --type=LoadBalancer
## Create a ConfigMap from a file
kubectl create configmap nginx-ghost --from-file=configs/ghost.conf --namespace=ghost
## Create a secret from a file
kubectl create secret generic db-user-pass --from-file=./username.txt --from-file=./password.txt
## Handy bash Aliases
alias k="kubectl"
alias kc="kubectl create -f"
alias kg="kubectl get"
alias pods="kubectl get pods"
alias allpods="kubectl get pods --all-namespaces"
alias rcs="kubectl get rc"
alias svcs="kubectl get services"
alias dep="kubectl get deployment"
alias kd="kubectl describe"
alias kdp="kubectl describe pod "
alias kds="kubectl describe service "
alias nodes="kubectl get nodes"
alias klogs="kubectl logs"
alias ns="kubectl get ns"
alias deploys="kubectl get deployment"
alias events="kubectl get events"
alias kexec="kubectl exec -it "
alias secrets="kubectl get secrets"
alias igs="kubectl get ingress"
alias contexts="kubectl config get-contexts"
alias ktop="kubectl top nodes"
## Handy bash functions
### Delete pod, don't wait
function dp(){
kubectl delete pod $1 --grace-period=0
}
### Secrets related functions
function encode(){
echo -n "$1" | base64
}
function decode(){
echo -n "$1" | base64 -D
}
function gettoken(){
kubectl get secret $(kubectl get secret | grep default | awk '{print $1}') -o yaml | grep "token:" | awk '{print $2}' | base64 -D
}
### set context quickly
function context(){
kubectl config use-context $1
}
### run bash in a pod
function dex(){
docker exec -it $1 bash
}
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