Deploy first deployment

  • Run on Master node
vagrant ssh k8s-master-01

create project folder

[vagrant@k8s-master-01 ~]$ mkdir controller
[vagrant@k8s-master-01 ~]$ cd controller
[vagrant@k8s-master-01 ~]$ vim nginx-deployment.yml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  selector:
    matchLabels:
      app: nginx
  replicas: 2 # tells deployment to run 2 pods matching the template
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.14.2
        ports:
        - containerPort: 80
  • Create a Deployment based on the YAML file:
[vagrant@k8s-master-01 controller]$ kubectl apply -f nginx-deployment.yml
deployment.apps/nginx-deployment created
  • Display information about the Deployment:
kubectl describe deployment nginx-deployment

Run kubectl get deployments to check if the Deployment was created.

If the Deployment is still being created, the output is similar to the following:

[vagrant@k8s-master-01 controller]$ kubectl get deployments

When you inspect the Deployments in your cluster, the following fields are displayed:

  • NAME lists the names of the Deployments in the namespace.
  • READY displays how many replicas of the application are available to your users. It follows the pattern ready/desired.
  • UP-TO-DATE displays the number of replicas that have been updated to achieve the desired state.
  • AVAILABLE displays how many replicas of the application are available to your users.
  • AGE displays the amount of time that the application has been running.

Notice how the number of desired replicas is 3 according to .spec.replicas field.

  • To see the ReplicaSet (rs) created by the Deployment, run kubectl get rs. The output is similar to this:
[vagrant@k8s-master-01 controller]$ kubectl get rs

ReplicaSet output shows the following fields:

  • NAME lists the names of the ReplicaSets in the namespace.

  • DESIRED displays the desired number of replicas of the application, which you define when you create the Deployment. This is the desired state.

  • CURRENT displays how many replicas are currently running.

  • READY displays how many replicas of the application are available to your users.

  • AGE displays the amount of time that the application has been running.-

  • To see the labels automatically generated for each Pod, run kubectl get pods --show-labels. The output is similar to:

[vagrant@k8s-master-01 controller]$ kubectl get pods --show-labels

-Running get pods should now show only the new Pods kubctl get pods

[vagrant@k8s-master-01 controller]$ kubectl get pods
  • To see network run kubectl get services
[vagrant@k8s-master-01 ~]$ kubectl get services
  • Delete deployment
[vagrant@k8s-master-01 ~]$ kubectl delete deployments.apps nginx-deployment 
deployment.apps "nginx-deployment" deleted
[vagrant@k8s-master-01 ~]$ kubectl delete pods  --all
No resources found