https://github.com/mmontes11/echoperator

🤖 Simple Kubernetes operator built from scratch with client-go
https://github.com/mmontes11/echoperator

client-go crd custom-resource-definition go golang high-availability kubernetes kubernetes-operator leader-election operator

Last synced: 7 months ago
JSON representation

🤖 Simple Kubernetes operator built from scratch with client-go

• Host: GitHub
• URL: https://github.com/mmontes11/echoperator
• Owner: mmontes11
• License: mit
• Created: 2021-07-12T18:28:05.000Z (about 4 years ago)
• Default Branch: main
• Last Pushed: 2023-03-16T18:18:02.000Z (over 2 years ago)
• Last Synced: 2024-10-12T02:50:29.073Z (12 months ago)
• Topics: client-go, crd, custom-resource-definition, go, golang, high-availability, kubernetes, kubernetes-operator, leader-election, operator
• Language: Go
• Homepage:
• Size: 101 KB
• Stars: 42
• Watchers: 3
• Forks: 8
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

README

          
# 🤖 echoperator 

[![CI](https://github.com/mmontes11/echoperator/actions/workflows/ci.yml/badge.svg)](https://github.com/mmontes11/echoperator/actions/workflows/ci.yml)

[![Release](https://github.com/mmontes11/echoperator/actions/workflows/release.yml/badge.svg)](https://github.com/mmontes11/echoperator/actions/workflows/release.yml)

[![Go Report Card](https://goreportcard.com/badge/github.com/mmontes11/echoperator)](https://goreportcard.com/report/github.com/mmontes11/echoperator)

[![Go Reference](https://pkg.go.dev/badge/github.com/mmontes11/echoperator.svg)](https://pkg.go.dev/github.com/mmontes11/echoperator)

[![Artifact HUB](https://img.shields.io/endpoint?url=https://artifacthub.io/badge/repository/echoperator)](https://artifacthub.io/packages/helm/mmontes/echoperator)

[![License: MIT](https://img.shields.io/badge/license-MIT-green.svg)](https://opensource.org/licenses/MIT)

Simple Kubernetes operator built from scratch with [client-go](https://github.com/kubernetes/client-go).

[Kubernetes operator pattern](https://kubernetes.io/docs/concepts/extend-kubernetes/operator/) implementation using the [client-go](https://github.com/kubernetes/client-go) library. Altough there are a bunch of frameworks for doing this ([kubebuilder](https://book.kubebuilder.io/), [operator framework](https://operatorframework.io/) ...), this example operator uses the tools provided by [client-go](https://github.com/kubernetes/client-go) for simplicity and flexibility reasons. 

[Medium article](https://betterprogramming.pub/building-a-highly-available-kubernetes-operator-using-golang-fe4a44c395c2) that explains how to build this operator step by step.

### Features

- Simple example to understand how a Kubernetes operator works.

- Manages [Echo CRDs](https://github.com/mmontes11/charts/blob/main/charts/echoperator/crds/echo.yml) for executing an `echo` inside a pod.

- Manages [ScheduledEcho CRDs](https://github.com/mmontes11/charts/blob/main/charts/echoperator/crds/scheduledecho.yml) for scheduling the execution of an `echo` inside a pod.

- High Availability operator using Kubernetes [lease](https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.20/#lease-v1-coordination-k8s-io) objects.

- Prometheus metrics.

- [Helm chart](https://github.com/mmontes11/charts/tree/main/charts/echoperator).

### Versioning 

|Echo|ScheduledEcho|Job|CronJob|Lease|Kubernetes|

|----|-------------|---|-------|-----|----------|

|v1alpha1|v1alpha1|v1|v1|v1|v1.21.x|

### Installation

```bash

helm repo add mmontes https://mmontes11.github.io/charts

helm install echoperator mmontes/echoperator

```

### Custom Resource Definitions (CRDs)

The helm chart installs automatically the [Custom Resource Definitions](https://kubernetes.io/docs/concepts/extend-kubernetes/api-extension/custom-resources/) needed for this operator to work. However, if you wanted to install them manually, you can find them in the [helm chart repo](https://github.com/mmontes11/charts/tree/main/charts/echoperator/crds).

### Example use cases

###### Hello world

- Client creates a [hello world Echo CRD](./manifests/examples/hello-world.yml).

- Operator receives a `Echo` added event.

- Operator reads the `message` property from the `Echo` and creates a `Job` resource.

- The `Job` resource creates a `Pod` that performs a `echo` command with the `message` property.

###### Scheduled hello world

- Client creates a [hello world ScheduledEcho CRD](./manifests/examples/hello-world-scheduled.yml).

- Operator receives a `ScheduledEcho` added event.

- Operator reads the `message` and `schedule` property from the `ScheduledEcho` and creates a `CronJob`.

- The `CronJob` schedules a `Job` creation using the `schedule` property.

- When scheduled, the `Job` resource creates a `Pod` that performs a `echo` command with the `message` property.