ls -alh# Random Notes and Useful Commands!!

Get info on Nodes Running: kubectl get nodes

Get info on Pods Running: kubectl get pods

Get info on Services Running: kubectl get services

Get detailed info on Nodes Running: kubectl describe nodes

Get detailed on Pods Running: kubectl describe pods

Get detailed on Services Running: kubectl describe services

Sample config file (YAML)

apiVersion: v1
kind: Pod
metadata:
    name: nginx
spec:
    containers:
    - name: nginx
      image: nginx:1.7.9
      ports:
      - containerPort: 80

Start Pod with sample config file: kubectl create -f nginx.yaml

Start a pod from command line: kubectl run busybox --image=busybox --restart=Never --tty -i --generator=run-pod/v1

To test the running box: wget -qO- http://10.244.0.8

To Delete a pod: kubectl delete pod busybox

To expose a port on a running pod: kubectl port-forward service <Hostport>:<ContainerPort>

• As an example: kubectl port-forward nginx 8008:80

Sample Config file with Label (YAML)

apiVersion: v1
kind: Pod
metadata:
    name: nginx
    labels:
        app: nginx
spec: 
    containers:
    - name: nginx
      image: nginx:1.7.9
      ports:
      - containerPort: 80

To get pods with a specific label: kubectl get pods -l app=nginx

To describe pods with a specific label: kubectl describe -l app=nginx

Sample config file for deployment (YAML)

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: nginx-deployment-prod
spec:
  replicas: 1
  template: 
    metadata:
      labels:
        app: nginx-deployment-prod
    spec: 
      containers:
      - name: nginx-deployment-prod
        image: nginx:1.7.9
        ports:
        - containerPort: 80

To deploy a deployment via config file: kubectl create -f nginx-deployment-prod

To get deployments: kubectl get deployments

To get all deployments: kubectl get deployments --show-all

To get deployments with a specific label: kubectl get deployments -l app=nginx-deployment-prod

To describe a specific deployment: kubectl describe deployments -l app=nginx-deployment-dev

Sample update config file for deployment(YAML)

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: nginx-deployment-dev
spec:
  replicas: 1
  template: 
    metadata:
      labels:
        app: nginx-deployment-dev
    spec: 
      containers:
      - name: nginx-deployment-dev
        image: nginx:1.8
        ports:
        - containerPort: 80

To apply an update to an existing deployment: kubectl apply -f nginx-deployment-dev-update.yaml

Sample replica-controller config file (YAML)

apiVersion: v1
kind: ReplicationController
metadata:
  name: nginx-www
spec:
  replicas: 2
  selector: 
    app: nginx
  template:
    metadata:
      name: nginx
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx
        ports:
        - containerPort: 80

To deploy a replication Controller: kubectl create -f nginx-multi.yaml

To get replication controller: kubectl get rc

To delete a replication controller kubectl delete rc nginx-www

Sample service config file (YAML)

apiVersion: v1
kind: Service
metadata:
  name: nginx-service
spec:
  ports:
  - port: 8000
    targetPort: 80
    protocol: TCP
  selector: 
    app: nginx

To deploy a service: kubectl create -f nginx-service.yaml

To get services: kubectl get svc

$ kubectl get svc
NAME            CLUSTER-IP     EXTERNAL-IP   PORT(S)    AGE
kubernetes      10.0.0.1       <none>        443/TCP    3d
nginx-service   10.0.138.251   <none>        8000/TCP   3m

To test service: wget -qO- 10.0.0.138.251:8000

To describe service deployed: kubectl describe svc nginx-service

To run temp pods from command line: kubectl run mysample --image=latest123/apache

To delete a running deployment: kubectl delete deployment mysample

To run multiple read replicas of a pod with labels: kubectl run myreplicas --image=latest123/apache --replicas=2 --labels=app=myapache,version=1.0

To run a specific command on a pod: kubectl exec myapache hostname

To run a specific command on a specific pod: kubectl exec myapache -c <CID> hostname

To interactively attach to a pod (without using kubectl attach): kubectl exec myapache -it -- /bin/bash

To get logs from a running pod with 1 container: kubectl logs myapache

To tail the logs from a container: kubectl logs --tail=1 myapache

To show logs for the previous N time: kubectl logs --since=(1s/1m/1h/1d) myapache

To follow the logs on a specific pod: kubectl logs -f myapache

To follow logs of a spcific pod: kubectl -f -c CID myapache

Run run a pod image from commandline: kubectl run myautoscale --image=latest123/apache --port=80 --labels=app=myautoscale

To apply a autoscaling policy to a deployment: kubectl autoscale deployment myautoscale --min=2 --max=6

To modify an existing autoscaling policy: kubectl scale --current-replicas=2 --replicas=4 deployment/myautoscale

Important Note:

• Once a pod is instantiated on a node it will stay there until it is deleted
  • Meaning once a pod on a host goes down. it will not be moved over to another node.
  • If the node goes down all the pods running on the node will be down and they will not come up on the other nodes
  • Once a node comes back up the deployed pods will come back up. Nothing will be redeployed
  • This means its important to keep track of node health so that deployments/pods can be scaled out incase of failure to nodes

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Kubernetes Needed!

These are the items you should consider before taking a cluster into production:

• Nodes Architecture (Networking)
• Backup etcd in Master (censo to monitor)
• Monitoring to detect failure on Master
  • Once detected, automation to failover master node
• Monitoring to scale up/down cluster * Automation to scale up/down cluster * Manual / ACI
• Blue/Green Deployment procedure
• Monitoring Nodes (Patch/Performance/Security)
• Container Log Monitoring
• Persistent Storage layer
• Demistfy ACS Magic
  • What is ACS doing?
  • What components is it configuring
  • Limitations
• DevOps how to deploy
• Diaster Recovery & High Avalibility of nodes in cluster
• Training
  • Increase competency across customer/partner operational and development team