##############################################################################
# KUBERNETES
# PDF: https://sematext.com/kubernetes-cheat-sheet/
# WEBSITE: https://kubernetes.io/
# DOCUMENTATION: https://kubernetes.io/docs/home
##############################################################################


##############################################################################
# CLIENT CONFIGURATION
##############################################################################


# Setup autocomplete in bash; bash-completion package should be installed first
source <(kubectl completion bash)

# View Kubernetes config
kubectl config view

# View specific config items by json path
kubectl config view -o jsonpath='{.users[?(@.name == "k8s")].user.password}'

# Set credentials for foo.kuberntes.com
kubectl config set-credentials kubeuser/foo.kubernetes.com --username=kubeuser --password=kubepassword

# Set active namespace
kubectl config set-context --current --namespace=namespace_name

##############################################################################
# VIEWING, FINDING RESOURCES
##############################################################################


# List all services in the namespace
kubectl get services

# List all pods in all namespaces in wide format
kubectl get pods -o wide --all-namespaces

# List all pods in json (or yaml) format
kubectl get pods -o json

# Describe resource details (node, pod, svc)
kubectl describe nodes my-node

# 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'

# Rolling update pods for frontend-v1
kubectl rolling-update frontend-v1 -f frontend-v2.json

# Scale a replicaset named 'foo' to 3
kubectl scale --replicas=3 rs/foo

# Scale a resource specified in "foo.yaml" to 3
kubectl scale --replicas=3 -f foo.yaml

# Execute a command in every pod / replica
for i in 0 1; do kubectl exec foo-$i -- sh -c 'echo $(hostname) > /usr/share/nginx/html/index.html'; done


##############################################################################
# MANAGE RESOURCES
##############################################################################


# Get documentation for pod or service
kubectl explain pods,svc

# Create resource(s) like pods, services or daemonsets
kubectl create -f ./my-manifest.yaml

# Apply a configuration to a resource
kubectl apply -f ./my-manifest.yaml

# Start a single instance of Nginx
kubectl run nginx --image=nginx

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

# Delete a resource
kubectl delete -f ./my-manifest.yaml


##############################################################################
# MONITORING & LOGGING
##############################################################################


# Deploy Heapster from Github repository
kubectl create -f deploy/kube-config/standalone/

# Show metrics for nodes
kubectl top node

# Show metrics for pods
kubectl top pod

# Show metrics for a given pod and its containers
kubectl top pod pod_name --containers

# Dump pod logs (stdout)
kubectl logs pod_name

# Stream pod container logs (stdout, multi-container case)
kubectl logs -f pod_name -c my-container


##############################################################################
# INTERACTING WITH RUNNING PODS
##############################################################################


# Run command in pod
kubectl exec pod_name -- command_name

# Run command in pod with multiple containers
kubectl exec pod_name -c container_name -- command_name

# Get terminal of pod
kubectl exec -it pod_name /bin/sh

# Get terminal of a container running in pod with multiple containers
kubectl exec -it pod_name -c container_name /bin/sh