Chapter 2 kubectl deployment doesn't work on a real cluster

[dwschulze]

In chapter 2 the command you show to deploy the myhello application gives a different output than you show when I run it on the master of a 3 node cluster:

$ kubectl run demo --image=dwschulze/myhello --port=9999 --labels app=demo
pod/demo created

The output you show is:

deployment.apps "demo" created

When I try to do the port forwarding it fails because I have no deployments.

Do I need a deployment.yaml to deploy this onto a real cluster, or is there a different kubectl command I use?

[dwschulze]

This is the command that is needed on a cluster:

$ sudo kubectl create deployment demo --image=demo

Maybe on a single node too?

[domingusj]

@dwschulze thanks for opening an issue!

Are you by chance running version 1.18 of Kubernetes?

I think the issue you are experiencing could be due to a change in the 1.18 release. The latest release of Kubernetes back when the book was published was 1.10 or 1.11 so this could be a case where Kubernetes has changed something and our example no longer works with newer versions.

After searching docs between 1.17 and 1.18 it looks like kubectl run no longer creates a Deployment:

1.17 docs (https://v1-17.docs.kubernetes.io/docs/reference/generated/kubectl/kubectl-commands#run) Creates a deployment or job to manage the created container(s).

1.18 docs (https://v1-18.docs.kubernetes.io/docs/reference/generated/kubectl/kubectl-commands#run) Create and run a particular image in a pod.

Let us know if that lines up with your current version and we'll get an update to the Known Issues section in the demo repo with an updated example.

[dwschulze]

I'm running 1.18.2. Should probably go into the errata too.

[domingusj]

PR merged with updated Known Issue in the README.

(Not sure why GitHub labeled the PR as "Closed" instead of "Merged").

Also submitted errata to O'Reilly.

Thank you @dwschulze for catching this!