14 Managing Pods with Deployments

This chapter covers

Deploying stateless workloads with the Deployment object
Horizontally scaling Deployments
Updating workloads declaratively
Preventing rollouts of faulty workloads
Implementing various deployment strategies

In the previous chapter, you learned how to deploy Pods via ReplicaSets. However, workloads are rarely deployed this way because ReplicaSets don’t provide the functionality necessary to easily update these Pods. This functionality is provided by the Deployment object type. By the end of this chapter, each of the three services in the Kiada suite will have its own Deployment object.

Before you begin, make sure that the Pods, Services, and other objects of the Kiada suite are present in your cluster. If you followed the exercises in the previous chapter, they should already be there. If not, you can create them by creating the kiada namespace and applying all the manifests in the Chapter14/SETUP/ directory with the following command:

$ kubectl apply -f SETUP -R

NOTE

You can find the code files for this chapter at https://github.com/luksa/kubernetes-in-action-2nd-edition/tree/master/Chapter14.

14.1 Introducing Deployments

14.1.1 Creating a Deployment

14.1.2 Scaling a Deployment

14.1.3 Deleting a Deployment

14.2 Updating a Deployment

14.2.1 The Recreate strategy

14.2.2 The RollingUpdate strategy

14.2.3 Configuring how many Pods are replaced at a time

14.2.4 Pausing the rollout process

14.2.5 Updating to a faulty version

14.2.6 Rolling back a Deployment

14.3 Implementing other deployment strategies

14.3.1 The Canary deployment strategy

14.3.2 The A/B strategy

14.3.3 The Blue/Green strategy

14.3.4 Traffic shadowing

14.4 Summary