Deployments

A Deployment provides declarative updates for Pods and ReplicaSets.

You describe a desired state in a Deployment, and the Deployment Controller changes the actual state to the desired state at a controlled rate. You can define Deployments to create new ReplicaSets, or to remove existing Deployments and adopt all their resources with new Deployments.

The following are typical use cases for Deployments:

Create a Deployment to rollout a ReplicaSet. The ReplicaSet creates Pods in the background. Check the status of the rollout to see if it succeeds or not.
Declare the new state of the Pods by updating the PodTemplateSpec of the Deployment. A new ReplicaSet is created and the Deployment manages moving the Pods from the old ReplicaSet to the new one at a controlled rate. Each new ReplicaSet updates the revision of the Deployment.
Rollback to an earlier Deployment revision if the current state of the Deployment is not stable. Each rollback updates the revision of the Deployment.
Scale up the Deployment to facilitate more load.
Pause the Deployment to apply multiple fixes to its PodTemplateSpec and then resume it to start a new rollout.
Use the status of the Deployment as an indicator that a rollout has stuck.
Clean up older ReplicaSets that you don’t need anymore.

Resources

OpenShiftKubernetes

Deployments

Managing Deployment Processes

DeploymentConfig Strategies

Route Based Deployment Strategies

Deployments

Scaling Deployments

References

apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-deployment
  labels:
    app: nginx
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
        - name: nginx
          image: bitnami/nginx:1.16.0
          ports:
            - containerPort: 8080

OpenshiftKubernetes

Create a Deployment

oc apply -f deployment.yaml

Get Deployment

oc get deployment my-deployment

Get Deployment's Description

oc describe deployment my-deployment

Edit Deployment

oc edit deployment my-deployment

Scale Deployment

oc scale deployment/my-deployment --replicas=3

Delete Deployment

oc delete deployment my-deployment

Create a Deployment

kubectl apply -f deployment.yaml

Get Deployment

kubectl get deployment my-deployment

Get Deployment's Description

kubectl describe deployment my-deployment

Edit Deployment

kubectl edit deployment my-deployment

Scale Deployment

kubectl scale deployment/my-deployment --replicas=3

Delete Deployment

kubectl delete deployment my-deployment

Activities

Task	Description	Link
*Try It Yourself*
Rolling Updates Lab	Create a Rolling Update for your application	Rolling Updates