https://github.com/tcdowney/sinatra-k8s-sample
A basic stateless Ruby app for experimenting with Kubernetes
https://github.com/tcdowney/sinatra-k8s-sample
kubernetes ruby sinatra
Last synced: about 1 year ago
JSON representation
A basic stateless Ruby app for experimenting with Kubernetes
- Host: GitHub
- URL: https://github.com/tcdowney/sinatra-k8s-sample
- Owner: tcdowney
- License: mit
- Created: 2019-11-03T17:11:50.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2022-12-01T01:52:45.000Z (over 3 years ago)
- Last Synced: 2025-04-24T01:02:21.710Z (about 1 year ago)
- Topics: kubernetes, ruby, sinatra
- Language: Ruby
- Size: 104 KB
- Stars: 4
- Watchers: 1
- Forks: 3
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# sinatra-k8s-sample
[](https://cloud.docker.com/u/downey/repository/docker/downey/sinatra-k8s-sample)
A basic stateless Ruby app for experimenting with Kubernetes
---
This repo contains the sample code of a basic Sinatra app called [Belafonte](https://en.wikipedia.org/wiki/The_Life_Aquatic_with_Steve_Zissou) that can be deployed to Kubernetes for learning and exploration.
It was written to be an example application for my blog post on [Cloud Native Buildpacks and kapp in Kubernetes](https://dev.to/downey/simplify-kubernetes-app-deployments-with-cloud-native-buildpacks-and-kapp-339b).
The app prints out some basic information about the `pod` it is running on and demonstrates inter-pod communication by fetching a UUID from another microservice that spits out UUIDs ([httpbin](https://github.com/postmanlabs/httpbin)).
## Building the Image
I use the [Cloud Native Buildpacks](https://buildpacks.io/) [`pack`](https://github.com/buildpack/pack) CLI and heroku Ruby buildpack to build and publish the container image for this app.
```bash
pack build downey/sinatra-k8s-sample --builder heroku/buildpacks --buildpack heroku/ruby --publish
```
If you want to publish to your own image repository, replace the `downey/sinatra-k8s-sample` portion above.
## Deploying to Kubernetes
I have been deploying to a Digital Ocean hosted Kubernetes cluster that has the following installed:
* [kubernetes/ingress-nginx](https://github.com/kubernetes/ingress-nginxhttps://github.com/kubernetes/ingress-nginx) for workload Ingress
* https://kubernetes.github.io/ingress-nginx/deploy/#gce-gke (followed the GKE steps for Digital Ocean)
* [cert-manager](https://github.com/jetstack/cert-manager) for automated provisioning of lets-encrypt TLS certs
* https://docs.cert-manager.io/en/latest/getting-started/install/kubernetes.html
* A lets-encrypt `ClusterIssuer` for `cert-manager`
```yaml
apiVersion: cert-manager.io/v1alpha2
kind: ClusterIssuer
metadata:
name: letsencrypt-prod
namespace: cert-manager
spec:
acme:
email: email@example.com # change to your email address
http01: {}
privateKeySecretRef:
name: letsencrypt-prod
server: https://acme-v02.api.letsencrypt.org/directory
solvers:
- http01:
ingress:
class: nginx
```
To deploy the app itself I have been using the [`kapp`](https://get-kapp.io/) CLI.
```bash
kapp deploy -a belafonte -f deploy
```
This will deploy everything in the `deploy` directory and `kapp` will ensure resources are applied in a reasonable order (e.g. namespaces and CRDs first) and it will wait until the status checks succeed for resources before continuing.
After that finished you can run `kapp inspect -a belafonte` and you should see all of the resources that were deployed. Example:
```bash
Resources in app 'belafonte'
Namespace Name Kind Owner Conds. Rs Ri Age
(cluster) belafonte Namespace kapp - ok - 33m
belafonte belafonte Certificate cluster 1/1 t ok - 33m
^ belafonte Deployment kapp 2/2 t ok - 33m
^ belafonte Endpoints cluster - ok - 33m
^ belafonte Ingress kapp - ok - 33m
^ belafonte Service kapp - ok - 33m
^ belafonte-1918113368 CertificateRequest cluster 1/1 t ok - 33m
^ belafonte-1918113368-3886681398 Order cluster - ok - 33m
^ belafonte-694ffdfdd4 ReplicaSet cluster - ok - 33m
^ belafonte-7c874788d7 ReplicaSet cluster - ok - 11s
^ belafonte-7c874788d7-lm6hj Pod cluster 4/4 t ok - 11s
^ httpbin Deployment kapp 2/2 t ok - 33m
^ httpbin Endpoints cluster - ok - 33m
^ httpbin Service kapp - ok - 33m
^ httpbin-85b9b4c565 ReplicaSet cluster - ok - 33m
^ httpbin-85b9b4c565-x2nmb Pod cluster 4/4 t ok - 33m
```