{"id":6279,"date":"2019-07-26T18:32:14","date_gmt":"2019-07-26T18:32:14","guid":{"rendered":"https:\/\/www.devopsschool.com\/blog\/?p=6279"},"modified":"2021-11-16T11:12:43","modified_gmt":"2021-11-16T11:12:43","slug":"working-with-kubernetes-cluster-using-kubectl-part-5-anatomy-api-request","status":"publish","type":"post","link":"https:\/\/www.devopsschool.com\/blog\/working-with-kubernetes-cluster-using-kubectl-part-5-anatomy-api-request\/","title":{"rendered":"Working with Kubernetes Pods & Deployment"},"content":{"rendered":"\n

deployment.yaml<\/strong><\/p>\n\n\n

apiVersion: apps\/v1\nkind: Deployment\nmetadata:\n  name: hello-world\n  labels:\n    app: hello-world\nspec:\n  replicas: 4\n  selector:\n    matchLabels:\n      app: hello-world\n  template:\n    metadata:\n      labels:\n        app: hello-world\n    spec:\n      containers:\n      - name: hello-world\n        image: gcr.io\/google-samples\/hello-app:1.0\n        ports:\n        - containerPort: 8080\n\n\n<\/code><\/span><\/pre>\n\n\n
pod.yaml<\/strong><\/p>\n\n\n
apiVersion: v1\nkind: Pod\nmetadata:\n  name: hello-world\nspec:\n  containers:\n  - name: hello-world\n    image: gcr.io\/google-samples\/hello-app:1.0<\/code><\/span><\/pre>\n\n
#Anatomy of an API Request<\/span>\n#Creating a pod with YAML<\/span>\nkubectl apply -f pod.yaml\n\n#Get a list of our currently running Pods<\/span>\nkubectl get pod hello-world\n\n#We can use the -v option to increase the verbosity of our request.<\/span>\n#Display requested resource URL. Focus on VERB, API Path and Response code<\/span>\nkubectl get pod hello-world -v 6<\/span> \n\n#Same output as 6, add HTTP Request Headers. Focus on application type, and User-Agent<\/span>\nkubectl get pod hello-world -v 7<\/span> \n\n#Same output as 7, adds Response Headers and truncated Response Body.<\/span>\nkubectl get pod hello-world -v 8<\/span> \n\n#Same output as 8, add full Response. Focus on the bottom, look for metadata<\/span>\nkubectl get pod hello-world -v 9<\/span> \n\n#Start up a kubectl proxy session, this will authenticate use to the API Server<\/span>\n#Using our local kubeconfig for authentication and settings<\/span>\nkubectl proxy &\ncurl http:\/\/localhost:8001\/api\/v1\/namespaces\/default\/pods\/hello-world | head -n 20<\/span>\n\nfg\nctrl+c\n\n#Watch, Exec and Log Requests<\/span>\n#A watch on Pods will watch on the resourceVersion on api\/v1\/namespaces\/default\/Pods<\/span>\nkubectl get pods --watch -v 6<\/span> &\n\n#We can see kubectl keeps the TCP session open with the server...waiting for data.<\/span>\nnetstat -plant | grep kubectl\n\n#Delete the pod and we see the updates are written to our stdout. Watch stays, sicne we're watching All Pods in the default namespace.<\/span>\nkubectl delete pods hello-world\n\n#But let's bring our Pod back...because we have more demos.<\/span>\nkubectl apply -f pod.yaml\n\n#And kill off our watch<\/span>\nfg\nctrl+c\n\n#Accessing logs<\/span>\nkubectl logs hello-world\nkubectl logs hello-world -v 6<\/span>\n\n#Start kubectl proxy, we can access the resource URL directly.<\/span>\nkubectl proxy &\ncurl http:\/\/localhost:8001\/api\/v1\/namespaces\/default\/pods\/hello-world\/log <\/span>\n\n#Kill our kubectl proxy, fg then ctrl+c<\/span>\nfg\nctrl+c\n\n#Authentication failure Demo<\/span>\ncp ~\/.kube\/config  ~\/.kube\/config.ORIG\n\n#Make an edit to our username changing user: kubernetes-admin to user: kubernetes-admin1<\/span>\nvi ~\/.kube\/config\n\n#Try to access our cluster, and we see GET on .\/api\/v1\/namespaces\/default\/pods?limit=500 returns a 403. Status, failure.<\/span>\nkubectl get pods -v 6<\/span>\n\n#Let's put our backup kubeconfig back<\/span>\ncp ~\/.kube\/config.ORIG ~\/.kube\/config\n\n#Test out access to the API Server<\/span>\nkubectl get pods \n\n#Missing resources, we can see the response code for this resources is 404...it's Not Found.<\/span>\nkubectl get pods nginx-pod -v 6<\/span>\n\n#Let's look at creating and deleting a deployment. We see a query for the existence of the deployment, then a 201 OK on the POST to create the deployment<\/span>\nkubectl apply -f deployment.yaml -v 6<\/span>\n\n#Get a list of the Deployments<\/span>\nkubectl get deployment \n\n#Clean up when we're finished. we see a DELETE 200OK and a GET 404.<\/span>\nkubectl delete deployment hello-world -v 6<\/span>\nkubectl delete pod hello-world\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
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What is kubernetes pods with example commands<\/a><\/blockquote>