orderedhttp-operator

Example k8s operator using operator-sdk

What the example looks to accomplish

The goal for this example is to demonstrate a method of launching PODs serially. Waiting to launch additional PODs until the currently running POD has reached a live state.

Clearly with a basic structure of this single docker image, the same functionality can be accomplished using Service and StatefulSet features. This project is meant to be a learning tool to allow iteration and discovery.

Requirements

brew install go
brew install operator-sdk

go version
# go version go1.12.5 darwin/amd64
operator-sdk version
# operator-sdk version: v0.8.1, commit: 33b3bfe10176f8647f5354516fff29dea42b6342

These were the current brew versions as of June 1st, 2019.

Clone and Run

If you have a kubernetes cluster available and you want to see this operator in action, follow these steps.

Docker Hub Repositories

Logon to your Docker Hub and create yourself two repositories:

• orderedhttp-operator
• nginx-delay

# change into a directory in your $GOPATH/src/
git clone https://github.com/splicemaahs/orderedhttp-operator.git
cd orderedhttp-operator/nginx-delay
vi Makefile
# change the `splicemaahs` reference to YOUR docker id, so it will push to your newly created
# repository
make build
make push
cd ..
export GO111MODULE=on
operator-sdk build YOURDOCKERID/orderedhttp-operator:latest
docker push YOURDOCKERID/orderedhttp-operator:latest

Create Kubernetes Resources

kubectl create -f deploy/crds/orderedhttp_v1alpha1_orderedhttp_crd.yaml
kubectl create -f deploy/service_account.yaml
kubectl create -f deploy/role.yaml
kubectl create -f deploy/role_binding.yaml
kubectl create -f deploy/operator.yaml
kubectl get pods
kubectl create -f deploy/crds/orderedhttp_v1alpha1_orderedhttp_cr.yaml

Check on Resources

kubectl get pods
kubectl describe OrderedHttp
kubectl logs $(kubectl get pods | grep orderedhttp-operator | tr -s ' ' | cut -d' ' -f1)

Delete Resources

kubectl delete -f deploy/crds/orderedhttp_v1alpha1_orderedhttp_cr.yaml
kubectl delete -f deploy/operator.yaml

kubectl create -f deploy/crds/orderedhttp_v1alpha1_orderedhttp_crd.yaml
kubectl create -f deploy/service_account.yaml
kubectl create -f deploy/role.yaml
kubectl create -f deploy/role_binding.yaml

kubectl get pods

Create Operator using operator-sdk

Create Docker Hub Repositories, if not already existing

Logon to your Docker Hub and create yourself two repositories:

• orderedhttp-operator
• nginx-delay

Build our custom nginx-delay docker image

mkdir -p nginx-delay
curl -s https://raw.githubusercontent.com/splicemaahs/orderedhttp-operator/master/nginx-delay/Dockerfile -o nginx-delay/Dockerfile
curl -s https://raw.githubusercontent.com/splicemaahs/orderedhttp-operator/master/nginx-delay/Makefile -o nginx-delay/Makefile
curl -s https://raw.githubusercontent.com/splicemaahs/orderedhttp-operator/master/nginx-delay/hello-plain-text.conf -o nginx-delay/hello-plain-text.conf
curl -s https://raw.githubusercontent.com/splicemaahs/orderedhttp-operator/master/nginx-delay/nginx-foreground -o nginx-delay/nginx-foreground
chmod 755 nginx-delay/nginx-foreground
cd nginx-delay
vi Makefile
# change the `splicemaahs` reference to YOUR docker id, so it will push to your newly created
# repository
make build
make push

Create new operator

# change into a directory in your $GOPATH/src/
export GO111MODULE=on
operator-sdk new orderedhttp-operator
cd orderedhttp-operator

Add an api

This output produces some warning lines, this appears to be normal as the resulting operator works without issue.

operator-sdk add api --api-version=orderedhttp.splicemachine.io/v1alpha1 --kind=OrderedHttp

Add Properties to the api

Create this patch file, then apply to the current sources

mkdir -p patches
curl -s https://raw.githubusercontent.com/splicemaahs/orderedhttp-operator/master/patches/apicode.patch -o patches/apicode.patch

git apply patches/apicode.patch
# the 'generate k8s' process builds code based on the properties added to the Spec and Status
# sections of ./pkg/apis/orderedhttp/v1alpha1/orderedhttp_types.go'
operator-sdk generate k8s

Add a controller

operator-sdk add controller --api-version=orderedhttp.splicemachine.io/v1alpha1 --kind=OrderedHttp

Add reconciler code to the controller

mkdir -p patches
curl -s https://raw.githubusercontent.com/splicemaahs/orderedhttp-operator/master/patches/controllercode.patch -o patches/controllercode.patch

# ./pkg/controller/orderedhttp/orderedhttp_controller.go
git apply patches/controllercode.patch

Update operator deploy for docker image name

vi deploy/operator.yaml
# change the 'image: REPLACE_IMAGE' reference to 'image: YOURDOCKERID/orderedhttp-operator:latest'

Build the operator docker image

go mod vendor # <- you need only run this once, and can rebuild with the 'build' command
# this process will fail on go syntax errors as it builds the code as part of the docker image build.
operator-sdk build YOURDOCKERID/orderedhttp-operator:latest
# push our image to Docker Hub
docker push YOURDOCKERID/orderedhttp-operator:latest

Create Kubernetes Resources (same as above)

# this installs/defines the Custom Resource Definition
kubectl create -f deploy/crds/orderedhttp_v1alpha1_orderedhttp_crd.yaml
# these create the ability for the operator to interact with the k8s controller
kubectl create -f deploy/service_account.yaml
kubectl create -f deploy/role.yaml
kubectl create -f deploy/role_binding.yaml
# this deploys the operator pod itself
kubectl create -f deploy/operator.yaml
kubectl get pods
# this creates an instance of our custom 'Kind'
kubectl create -f deploy/crds/orderedhttp_v1alpha1_orderedhttp_cr.yaml

Check on Resources (same as above)

kubectl get pods
kubectl describe OrderedHttp
kubectl logs $(kubectl get pods | grep orderedhttp-operator | tr -s ' ' | cut -d' ' -f1)

Delete Resources (same as above)

kubectl delete -f deploy/crds/orderedhttp_v1alpha1_orderedhttp_cr.yaml
kubectl delete -f deploy/operator.yaml

kubectl create -f deploy/crds/orderedhttp_v1alpha1_orderedhttp_crd.yaml
kubectl create -f deploy/service_account.yaml
kubectl create -f deploy/role.yaml
kubectl create -f deploy/role_binding.yaml

kubectl get pods