Operator SDK with Go (PodSet)

Start minishift cluster locally.

./start_minishift.sh

Login as admin

oc login -u system:admin

Ensure you are using myproject

oc project myproject

Configure Your machine to use operator sdk
Operator-SDK Installation

Create a new Go-based Operator SDK project for the PodSet (PodSet )

export PATH=$PATH:/usr/local/bin:$GOPATH/bin
export GOPATH=$HOME/go
mkdir -p $GOPATH/src/github.com/redhat/
cd $GOPATH/src/github.com/redhat/
operator-sdk new podset-operator --type=go #--skip-git-init

cd into podset directory

cd podset-operator/

Lets add a new Custom Resource Definition(CRD) API called PodSet

operator-sdk add api --api-version=app.example.com/v1alpha1 --kind=PodSet

Add a new Controller to the project that will watch and reconcile the PodSet resource

operator-sdk add controller --api-version=app.example.com/v1alpha1 --kind=PodSet

Confirm the CRD was successfully created.

oc get crd

Open IDE or use vim

code .
or
atom .

Lets inspect the Custom Resource Definition manifest*

cat deploy/crds/app_v1alpha1_podset_crd.yaml

Deploy your PodSet Custom Resource Definition to the live OpenShift Cluster.

oc create -f deploy/crds/app_v1alpha1_podset_crd.yaml

edit pkg/apis/app/v1alpha1/podset_types.go file on lines 10 - 18

// PodSetSpec defines the desired state of PodSet
type PodSetSpec struct {
    Replicas int32 `json:"replicas"`
}

// PodSetStatus defines the observed state of PodSet
type PodSetStatus struct {
    PodNames []string `json:"podNames"`
}

After modifying the podset_types.go file always run the following command to update the generated code for that resource type:

operator-sdk generate k8s

Edit the pkg/controller/podset/podset_controller.go

curl -OL https://gist.githubusercontent.com/madorn/bba19ea9bd4d0086b672a38ea5c65422/raw/a663f0f8a67c544134460c203f50d26b746faed4/podset_controller.go
# compare and replace with code found in the above link.
mv podset_controller.go podset_controller.bak.go
git diff  podset_controller.go pkg/controller/podset/podset_controller.go # or use IDE

Replace/Customize the Operator Logic

vim pkg/controller/podset/podset_controller.go
rm podset_controller.bak.go

Run the Operator Locally (Inside the Cluster) Test our logic by running our Operator outside the cluster via our kubeconfig credentials.

export OPERATOR_NAME=podset-operator #used by prometheus
operator-sdk up local --namespace myproject

Login Quay

docker login -u="username" -p="password" quay.io

Lets build and push the app-operator image to a public registry such as quay.io

ENDPOINT="takinosh"
OPERATORNAME="podset-operator"
operator-sdk build quay.io/${ENDPOINT}/${OPERATORNAME}
docker push quay.io/${ENDPOINT}/${OPERATORNAME}

Confirm quay.io repo is public

Lets update the operator manifest to use the built image name (if you are performing these steps on OSX, see note below)

sed -i 's|REPLACE_IMAGE|quay.io/'${ENDPOINT}'/'${OPERATORNAME}'|g' deploy/operator.yaml
# On OSX use:
sed -i "" 's|REPLACE_IMAGE|quay.io/'${ENDPOINT}'/'${OPERATORNAME}'|g' deploy/operator.yaml

Check if deploy/operator.yaml is correct

grep "${ENDPOINT}/${OPERATORNAME}" deploy/operator.yaml

Setup Service Account

oc create -f deploy/service_account.yaml

Setup RBAC

oc create -f deploy/role.yaml
oc create -f deploy/role_binding.yaml

In a new terminal or IE, inspect the Custom Resource manifest:

cat deploy/crds/app_v1alpha1_podset_cr.yaml

Ensure your kind: PodSet Custom Resource (CR) is updated with spec.replicas. Manually change if needed.

apiVersion: app.example.com/v1alpha1
kind: PodSet
metadata:
  name: example-podset
spec:
  replicas: 3

Deploy the app-operator

oc create -f deploy/operator.yaml

Runs the kube-openapi OpenAPIv3 code generator for all Custom Resource Definition (CRD) API tagged fields under pkg/apis/….

operator-sdk generate openapi

Deploy your PodSet Custom Resource to the live OpenShift Cluster:

oc create -f deploy/crds/app_v1alpha1_podset_cr.yaml

Check your Minishift cluster:

Optional: Delete Minishift Cluster

./delete_minishift.sh

Run the Etcd Operator Training on learn.openshift.com for in depth training.
openshift - Operator SDK with Go (PodSet)

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