[topology label] add new label operator.habitat.sh/topology

[surajssd]

Renaming the topology label from just topology to
operator.habitat.sh/topology.

Fixes #309

[surajssd]

@indradhanush can you PTAL?

[surajssd]

When the operator with this change is deployed, it updates the labels inside the StatefulSet that already exists, this leads to deletion of existing pod and re-creation of new one.

With following events

0s        0s        1         example-standalone-habitat-0.154a601bee720296   Pod       spec.containers{habitat-service}   Normal    Killing   kubelet, minikube   Killing container with id docker://habitat-service:Need to kill Pod
0s        0s        1         example-standalone-habitat-0.154a601c4f5af632   Pod                 Normal    Scheduled   default-scheduler   Successfully assigned example-standalone-habitat-0 to minikube        
0s        10m       6         example-standalone-habitat.154a5f85a74d6e69   StatefulSet             Normal    SuccessfulCreate   statefulset-controller   create Pod example-standalone-habitat-0 in StatefulSet example-standalone-habitat successful
0s        0s        1         example-standalone-habitat.154a601c553527f4   Habitat             Normal    ConfigMapUpdated   habitat-controller   Removed peer IP from ConfigMap                                  
0s        0s        2         example-standalone-habitat.154a601c553527f4   Habitat             Normal    ConfigMapUpdated   habitat-controller   Removed peer IP from ConfigMap                                  
0s        0s        1         example-standalone-habitat-0.154a601c5a318ee4   Pod                 Normal    SuccessfulMountVolume   kubelet, minikube   MountVolume.SetUp succeeded for volume "config"           
0s        0s        1         example-standalone-habitat-0.154a601c5a3641b6   Pod                 Normal    SuccessfulMountVolume   kubelet, minikube   MountVolume.SetUp succeeded for volume "default-token-clkdd"
0s        1s        3         example-standalone-habitat.154a601c553527f4   Habitat             Normal    ConfigMapUpdated   habitat-controller   Removed peer IP from ConfigMap                                  
0s        0s        1         example-standalone-habitat-0.154a601c8b0e4721   Pod       spec.containers{habitat-service}   Normal    Pulling   kubelet, minikube   pulling image "habitat/redis-hab"              
0s        0s        1         example-standalone-habitat-0.154a601d75eea4aa   Pod       spec.containers{habitat-service}   Normal    Pulled    kubelet, minikube   Successfully pulled image "habitat/redis-hab"  
0s        0s        1         example-standalone-habitat-0.154a601d820e072c   Pod       spec.containers{habitat-service}   Normal    Created   kubelet, minikube   Created container                              
0s        0s        1         example-standalone-habitat-0.154a601d8cdbf692   Pod       spec.containers{habitat-service}   Normal    Started   kubelet, minikube   Started container                              
0s        0s        1         example-standalone-habitat.154a601dbc96d81b   Habitat             Normal    ConfigMapUpdated   habitat-controller   Updated peer IP in ConfigMap 

cc: @krnowak

[krnowak]

Two things need to happen before we can merge this PR:

• we need to keep the old topology label and we need to remember to add some entry to the changelog when we do a release that this label is deprecated (for say, two releases) and will be dropped in future
• I'd prefer [spec][backwards incompatible] drop support for v1beta1 #331 to be merged first.

[krnowak]

I'd keep the old constant and add a new one, instead of replacing it. The reason behind it is that the code that was filtering pods by the old topology label will stop working after replacing. So, for now, I would keep the old label intact and add a new one.

[surajssd]

What do you mean by

code that was filtering pods by the old topology label

because adding a new label will update the StatefulSet and willl also re-create the pod.

[krnowak]

After this change something like kubectl get pods -l topology=leader will not show the pods it used to show, because they won't have the topology label anymore. They will have operator.habitat.sh/topology instead. That's why I would like to keep the old label and add a new one. The old label could be removed after some deprecation period.

[surajssd]

cool gotcha!

[krnowak]

As I mentioned earlier - let's keep the old label too.

[krnowak]

Same here.

[krnowak]

Please rebase.

[surajssd]

@krnowak rebased!

[surajssd]

@krnowak rebased PTAL :-)

[krnowak]

LFAD.

[krnowak]

Would be nice to do the similar thing for other labels we add there I think.