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

Chapter 8 ■ Using Rolling Updates
Make some more rolling updates. For example, the rolling update shown in Figure 8-30 sets the image
tag to 5.6.
Figure 8-30. Applying a rolling update to the mysql Docker image tag
The kubectl set image command does not verify the validity of a tag. For example, suppose a mysql
image with the invalid tag 5.5.5 is also used for a rolling update and the deployment is rolled out. Some of the
pods of the old RC are stopped, but new pods are not started. Listing the pods shows that some of the pods
have the Status ImagePullBackOff, or show another error message as illustrated in Figure 8-31.
Figure 8-31. Rolling update with an invalid image tag
As another example, rolling-update and roll out a deployment using the image mysql:latest. The
deployment also is rolled out. But as indicated in the deployment description, only two of the pods are
available, as shown in Figure 8-32.
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