operator-sdk: A Go repository from ylascombe

Project Status: pre-alpha

The project is currently pre-alpha and it is expected that breaking changes to the API will be made in the upcoming releases.

See the design docs for planned work on upcoming milestones.

Overview

This project is a component of the Operator Framework, an open source toolkit to manage Kubernetes native applications, called Operators, in an effective, automated, and scalable way. Read more in the introduction blog post.

Operators make it easy to manage complex stateful applications on top of Kubernetes. However writing an operator today can be difficult because of challenges such as using low level APIs, writing boilerplate, and a lack of modularity which leads to duplication.

The Operator SDK is a framework designed to make writing operators easier by providing:

High level APIs and abstractions to write the operational logic more intuitively
Tools for scaffolding and code generation to bootstrap a new project fast
Extensions to cover common operator use cases

Workflow

The SDK provides the following workflow to develop a new operator:

Create a new operator project using the SDK Command Line Interface(CLI)
Define new resource APIs by adding Custom Resource Definitions(CRD)
Specify resources to watch using the SDK API
Define the operator reconciling logic in a designated handler and use the SDK API to interact with resources
Use the SDK CLI to build and generate the operator deployment manifests

At a high level an operator using the SDK processes events for watched resources in a user defined handler and takes actions to reconcile the state of the application.

Prerequisites

dep version v0.5.0+.
git
go version v1.10+.
docker version 17.03+.
kubectl version v1.10.0+.
Access to a kubernetes v.1.10.0+ cluster.

Quick Start

First, checkout and install the operator-sdk CLI:

$ mkdir -p $GOPATH/src/github.com/operator-framework
$ cd $GOPATH/src/github.com/operator-framework
$ git clone https://github.com/operator-framework/operator-sdk
$ cd operator-sdk
$ git checkout master
$ make dep
$ make install

Create and deploy an app-operator using the SDK CLI:

# Create an app-operator project that defines the App CR.
$ mkdir -p $GOPATH/src/github.com/example-inc/
# Create a new app-operator project
$ cd $GOPATH/src/github.com/example-inc/
$ operator-sdk new app-operator
$ cd app-operator

# Add a new API for the custom resource AppService
$ operator-sdk add api --api-version=app.example.com/v1alpha1 --kind=AppService

# Add a new controller that watches for AppService
$ operator-sdk add controller --api-version=app.example.com/v1alpha1 --kind=AppService

# Build and push the app-operator image to a public registry such as quay.io
$ operator-sdk build quay.io/example/app-operator
$ docker push quay.io/example/app-operator

# Update the operator manifest to use the built image name
$ sed -i 's|REPLACE_IMAGE|quay.io/example/app-operator|g' deploy/operator.yaml

# Setup Service Account
$ kubectl create -f deploy/service_account.yaml
# Setup RBAC
$ kubectl create -f deploy/role.yaml
$ kubectl create -f deploy/role_binding.yaml
# Setup the CRD
$ kubectl create -f deploy/crds/app_v1alpha1_appservice_crd.yaml
# Deploy the app-operator
$ kubectl create -f deploy/operator.yaml

# Create an AppService CR
# The default controller will watch for AppService objects and create a pod for each CR
$ kubectl create -f deploy/crds/app_v1alpha1_appservice_cr.yaml

# Verify that a pod is created
$ kubectl get pod -l app=example-appservice
NAME                     READY     STATUS    RESTARTS   AGE
example-appservice-pod   1/1       Running   0          1m

# Cleanup
$ kubectl delete -f deploy/app_v1alpha1_appservice_cr.yaml
$ kubectl delete -f deploy/operator.yaml
$ kubectl delete -f deploy/role.yaml
$ kubectl delete -f deploy/role_binding.yaml
$ kubectl delete -f deploy/service_account.yaml
$ kubectl delete -f deploy/crds/app_v1alpha1_appservice_crd.yaml

User Guide

To learn more about the operator-sdk, see the user guide.

Samples

To explore any operator samples built using the operator-sdk, see the operator-sdk-samples.

Contributing

See CONTRIBUTING for details on submitting patches and the contribution workflow.

Reporting bugs

See reporting bugs for details about reporting any issues.

License

Operator SDK is under Apache 2.0 license. See the LICENSE file for details.

ylascombe/operator-sdk