148422597X Kubernetes Management Design Patterns [Vohra 2017-01-29] {E559F6BB}

Chapter 8 ■ Using Rolling Updates
The following command creates a rolling update on the RC with a new image tag and new RC name.
The –a option displays all labels, and the --poll-interval specifies the interval between polling the
replication controller for status after update.
kubectl rolling-update mysql-v1
mysql --image=mysql:latest -a --poll-interval=3ms
The RC mysql-v1 is rolling-updated to mysql as shown in Figure 8-8. Subsequently the RC mysql-v1 is
deleted.
Figure 8-8. Rolling update to an RC using a Docker image
After the update, list the RC and the pods:
kubectl get rc
kubectl get pods
A different RC, mysql, and different pods are now listed, as shown in Figure 8-9.
Figure 8-9. Listing the RC and pods
A rolling update on an RC does not have to use a new RC name. As an example, perform a rolling update
with a new image tag and same RC name.
kubectl rolling-update mysql
--image=mysql:5.6
For the purpose of updating the RC a temporary RC is created and the update is applied to the RC as
shown in Figure 8-10. Subsequently the original RC mysql is deleted and the temporary RC is renamed to
mysql, as a result keeping the RC name the same.
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