Zero Downtime Deployment with Kubernetes + HELM 📝

This repository is intended to teach how to rollout changes a Docker HelloWorld image into the Kubernetes clusters.

If you are here just for fun or learning, you will need to machines, Just 4Fun

Prerequisites 🗺️

• kubectl client configured (In other words, you need to have a k8s cluster.)
• Helm installed (Helm initialized in the cluster)

Intalling App 📥

PS: By default the app deployed version will be v1.0.0

1. Installing:

$ cd hello-world-web-chart/
$ helm install --name hello-world-web .

2. Check Installation:

http://<your ip address>:31000

Creating Docker Image 🐳

1. Change the file version:

vi app/index.html

2. Building Image:

$ docker build -t hello-world-web:<VERSION> .

3. Tagging the Image:

$ docker tag <IMAGE ID> <DOCKERHUB USER>/hello-world-web:<VERSION>

4. Pushing to your repository:

$ docker push <DOCKERHUB USER>/hello-world-web:<VERSION>

5. Testing Docker image:

$ docker run -d -p80:80 <DOCKERHUB USER>/hello-world-web:<VERSION>

6. Now follow the steps bellow

ZeroDownTime Rollout ⏰

PS: Before rolling out update login in another terminal of your cluster and run the command bellow:

$ while true; do  curl 0:31000; sleep 1s;

1. Change the configurations according to your container in values.yml:

$ cd hello-world-web-chart/
$ vi values.yml

2. Edit Chart.yml with new versions of the application:

$ vi Chart.yml

3. Upgrading the app:

$ helm upgrade hello-world-web .

4. Check the version at the other terminal and the current terminal:

$ helm list
NAME            REVISION        UPDATED                         STATUS          CHART                           APP VERSION     NAMESPACE
hello-world-web 2               Fri May 24 16:55:54 2019        DEPLOYED        hello-world-web-chart-2.0.0     2.0.0           default

Helm Rollback ⏪

1. Check the revision number:

$ helm history hello-world-web
REVISION        UPDATED                         STATUS          CHART                           DESCRIPTION
1               Fri May 24 16:29:23 2019        SUPERSEDED      hello-world-web-chart-1.0.0     Install complete
2               Fri May 24 16:55:54 2019        DEPLOYED        hello-world-web-chart-2.0.0     Upgrade complete

2. Use the revision number in the command bellow:

$ helm rollback hello-world-web <REVISION NUMBER>

Deleting ❌

helm del --purge hello-world-web

Just 4Fun 👾 🎮 🎲

Prerequisites 🗺️

• Vagrant
• Virtual Box
• Ansible

$ cd k8s-cluster/
$ vagrant up
$ vagrant ssh k8s-master
$ vagrant@k8s-master:~$ kubectl get nodes
NAME         STATUS   ROLES    AGE     VERSION
k8s-master   Ready    master   18m     v1.13.3
node-1       Ready    <none>   12m     v1.13.3
node-2       Ready    <none>   6m22s   v1.13.3