Using the “change-cause” Kubernetes annotation as a changelog

Suppose you have an application you are deploying to your kubernetes cluster. For most purposes, running kubectl rollout history deployments/your-app will give you a very simple revision history.

$ kubectl rollout history deployments/awesome-app
1         <none>

However, what if you had multiple deployments by different people. How would you know what was the reason for the deployment? Especially when you have something like this?

1         <none>
100       <none>
101       <none>
102       <none>

It is possible to set a value into the change-cause field via an annotation, but that field is quite volatile, it is also filled/replaced if someone uses the --record flag when doing an apply. However, it can be utilised to make it much more useful:

11        Deploy new version of awesome-app to test environment
12        Deploy new version of awesome-app to staging environment
13        Deploy new version of awesome-app, Thu 21 Jun 07:01:03 BST 2018
14        Deploy new version of awesome-app with integration to gitlab v0.0.0 [test]

How is this done? Pretty simply, actually. here’s a snippet from the deploy script I use.

echo Deploy message?
if [ -z "$MESSAGE" ]; then
  MESSAGE="Deploy new version of awesome-app, $(date)"
  echo Blank message detected, defaulting to \"$MESSAGE\"
echo Deploy updates...
cat deploy.yaml | sed s/'SUB_TIMESTAMP'/"$(date)"/g | kubectl replace -f -
kubectl annotate deployment awesome-app"$MESSAGE" --record=false --overwrite=true
kubectl rollout status deployments/awesome-app
kubectl rollout history deployment awesome-app

For lines 1 to 6, I read in a message from the terminal to populate the annotation, and if nothing is provided, a default is used.
On line 8, I replace the timestamp to trigger a change to the deployment (this can be anything, for example, changing the version tag of your docker image from awesome-app:release-1.0 to awesome-app:release-1.1)

Note that I used replace and not applyreplace will reset the deployment declaration, and since my deploy yaml does NOT contain a change-cause annotation, replace will remove the annotation.

On line 9, I annotate the deployment, making sure I don’t record it and overwrite the annotation in the event it’s there already (though those two switches might be redundant)

On line 10 I check the status of the rollout — this blocks until it is complete

On line 11, I then dump the deployment history.

This is an example of a script run:

$ ./
Deploy message?
[typed] Deploy new version of awesome-app with gitlab integration v0.0.0 [test]
Deploy updates...
deployment "awesome-app" replaced
deployment "awesome-app" annotated
Waiting for rollout to finish: 1 old replicas are pending termination...
deployment "awesome-app" successfully rolled out
deployments "awesome-app"
11        Deploy new version of awesome-app, Thu 21 Jun 07:00:19 BST 2018
12        Deploy new version of awesome-app, Thu 21 Jun 07:00:52 BST 2018
13        Deploy new version of awesome-app, Thu 21 Jun 07:01:03 BST 2018
14        Deploy new version of awesome-app with integration to gitlab v0.0.0 [test]


Cloudy and slightly drizzly run today.

Played some Eurobeat on Spotify and that was fun keeping time to the beat. Annoyingly Spotify removed the running mode which allowed me an auto-playlist of specific BPM tracks. Now I have no idea what music to play to help keep pace. Spotify have added some static playlists giving a range of BPM, but that doesn’t work as well.


c25k training. A relatively warm but not overly-hot today. Week 3 runs. 1.5 min run/1.5 min walk, then 3.0 min run/3.0 min walk, then repeat for 4 run/walk intervals.

Felt worked out, but not overly pushed for some reason….

FitBit and ZenLabs were in disagreement about the distance I ran again — ZenLabs said 4.1 km, FitBit said 3.59

Microsoft to Acquire GitHub

Sad news that M$ are to acquire GitHub. I suspect I’ll start getting Windows adverts in my email inbox soon as my office uses GitHub

On the plus side, this LinuxJournal article has proposed some alternatives. GitLab is a good one and even mentioned on some job listings so I guess I’ll move my repos there.

I’ll be removing my GitHub repos…

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