I followed the guide by subicura to do this practice.
If you’ve installed minukube and kubectl, you can start right away.
What is Minikube?
miniKube is a tool that quickly sets up a local Kubernetes cluster on macOS, Linux, and Windows. In other words, minikube makes it easy to create a Kubernetes cluster locally. It can even manage multiple clusters. To run a Kubernetes cluster, you need to install at least the scheduler, controller, api-server, etcd, kubelet, and kube-proxy. Depending on your needs, you may also need to install DNS, an ingress controller, a storage class, and so on. Installing Kubernetes is an important process, but when you’re first learning, it’s more important to learn how to use it in practice than to focus on installation. Minikube is a tool that makes this setup easy and quick. It can be used on Windows, macOS, and Linux, supports various virtual environments, and runs without problems in most environments. Source
1. Start Minikube
Run minikube with the minikube start command.
2. Write a YAML file
apiVersion: apps/v1
kind: Deployment
metadata:
name: wordpress-mysql
labels:
app: wordpress
spec:
selector:
matchLabels:
app: wordpress
tier: mysql
template:
metadata:
labels:
app: wordpress
tier: mysql
spec:
containers:
- image: mariadb:10.7
name: mysql
env:
- name: MYSQL_DATABASE
value: wordpress
- name: MYSQL_ROOT_PASSWORD
value: password
ports:
- containerPort: 3306
name: mysql
---
apiVersion: v1
kind: Service
metadata:
name: wordpress-mysql
labels:
app: wordpress
spec:
ports:
- port: 3306
selector:
app: wordpress
tier: mysql
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: wordpress
labels:
app: wordpress
spec:
selector:
matchLabels:
app: wordpress
tier: frontend
template:
metadata:
labels:
app: wordpress
tier: frontend
spec:
containers:
- image: wordpress:5.9.1-php8.1-apache
name: wordpress
env:
- name: WORDPRESS_DB_HOST
value: wordpress-mysql
- name: WORDPRESS_DB_NAME
value: wordpress
- name: WORDPRESS_DB_USER
value: root
- name: WORDPRESS_DB_PASSWORD
value: password
ports:
- containerPort: 80
name: wordpress
---
apiVersion: v1
kind: Service
metadata:
name: wordpress
labels:
app: wordpress
spec:
type: NodePort
ports:
- port: 80
selector:
app: wordpress
tier: frontend
I copied it over because I don’t know exactly what it means yet.
3. kubectl apply
Use the apply command from kubectl to apply the desired state.
Once it’s applied, check it with the kubectl get all command.
Now let’s run the deployed wordpress.
4. Run it
Run minikube service ${service-name}. For ${service-name}, enter wordpress, since the kubectl get all command shows service/wordpress.
It returns this and opens a browser window.
5. Scale it to two replicas
At the moment, kubectl get all shows only one pod/wordpress. If you delete the pod with kubectl delete ${pod-name},
the connection is interrupted like this. However, Kubernetes immediately brings it back, so it becomes accessible again shortly afterward.
Now let’s scale it to two replicas so that deleting one doesn’t interrupt the connection.
Open the wordpress-k8s.yml file and
apiVersion: apps/v1
kind: Deployment
metadata:
name: wordpress
labels:
app: wordpress
spec:
replicas: 2
selector:
matchLabels:
app: wordpress
tier: frontend
template:
metadata:
labels:
app: wordpress
tier: frontend
spec:
containers:
- image: wordpress:5.9.1-php8.1-apache
name: wordpress
env:
- name: WORDPRESS_DB_HOST
value: wordpress-mysql
- name: WORDPRESS_DB_NAME
value: wordpress
- name: WORDPRESS_DB_USER
value: root
- name: WORDPRESS_DB_PASSWORD
value: password
ports:
- containerPort: 80
name: wordpress
under spec in the wordpress Deployment, add replicas: 2, then apply it again with kubectl apply -f wordpress-k8s.yml.
Then check with kubectl get all:
Unlike before, we can see two pod/wordpress instances. Now, deleting one pod/wordpress won’t interrupt the connection.
