Crd-assignment

Resource Creation

• For starting minikube $ minikube start
• Resource Type = App, Group = phoenix.com, version = v1aplha1
• Create resource file app.yaml with Spec details
• Added resource definition by $ kubectl create -f artifacts/apps/crd.yaml
• Creating an object of CRD by declaring app.yaml
• Added crd based object by $ kubectl create -f artifacts/apps/app.yaml
• Checking if object is running by $ kubeclt get app

NAME            AGE
phoenix-app-1   43s

Controller Creation

• point to the directory: `cd home/{user}/go/src/github.com/{github-username}/Crd-assignment
• create folder pkg/apis/{Group}/{version} and add types.go file
• Add definitions of cluster type and its fields(Spec, Status, List) in the types.go file
• We need to specifiy that the Kluster Spec is a Kubernetes object, for this we will create a register.go file in the same directory that will register the Kluster type to scheme.
• Create doc.go for declaring tabs. tabs are basically used to call a particular instruction for all valid instance over the codebase. For eg- +k8s:deepcopy-gen=package means that a deep copy must be generated at every package. This is global. If we declare it anywhere else, it will be local.
• Create register.go in the directory pkg/apis/{Group} as every directory must contain a go file.
• Install code-generator by $ go get k8s.io/code-generator
• Create alias path $ execDir=~/go/pkg/mod/k8s.io/[email protected]
• Create deepcopy, lister, clientset and informers by runnning $ "${execDir}"/generate-groups.sh all github.com/vinay272001/Crd-assignment/pkg/client github.com/vinay272001/Crd-assignment/pkg/apis phoenix.com:v1alpha1 --go-header-file "${execDir}"/hack/boilerplate.go.txt
• Create the main.go. In main.go we will declare the kubeconfig, create clientsets and the generate clusters.
• To add all dependency : $ go mod tidy
• Create the controller.go.

Running Controller

• build the controller using $ go build -o Crd-assignment
• To start the controller `$ ./crd-assignment
• When custom resource is created using kubectl create -f app.yaml number of running pods will sync with the count field in CR and the pods will echo message and count in it
• For deleting a CR
• $ kubectl delete -f artifacts/apps/app.yml, this will make sure all the associated pods are deleted as well.

For deleting a pod

• $ kubectl delete pod {podname} After deleting the pod, they won't spawn back

To get podname

• $ kubectl get pods