• kubernetes: Rollback a deployment update

    2 min read

    kubectl rolling update history undo

    When performing rolling updates we can see it's history using kubectl rollout history:

    $ kubectl rollout history deploy pet2cattle
deployment.apps/pet2cattle 
REVISION  CHANGE-CAUSE
100       <none>
101       <none>
102       <none>
103       <none>
104       <none>
105       <none>
106       <none>
107       <none>
109       kubectl scale deployment/pet2cattle --replicas=2 --record=true
110       kubectl scale deployment/pet2cattle --replicas=5 --record=true
111       kubectl scale deployment/pet2cattle --replicas=1 --record=true

    If have any problem with the update we can undo and update using kubectl rollout undo

    25/05/2021

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  • Keeping record of the change cause using the --record flag

    3 min read

    kubectl rolling update history change-cause

    On Kubernetes, when we update objects such as a deployment or a daemonset we can check it's rollout history using kubectl rollout history:

    $ kubectl rollout history deploy pet2cattle
deployment.apps/pet2cattle 
REVISION  CHANGE-CAUSE
21        <none>
22        <none>
23        <none>
24        <none>
26        <none>
28        <none>
29        <none>
30        <none>
32        <none>
33        <none>
34        <none>

    By default we won't be able to see a change cause, but we can fill this gap by setting the command that triggered the update adding the --record flag as follows:

    $ kubectl scale deployment/pet2cattle --replicas 2 --record
deployment.apps/pet2cattle scaled

    18/05/2021

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  • Rolling updates on Kubernetes deployments

    2 min read

    Deployment pod rolling update

    There are several strategies available for updating a deployment on Kubernetes, by default it will trigger a rolling update: It will deploy the new version before tearing down the old one so there's no downtime associated to it.

    Let's see how we can see this process by applying an update to a deployment:

    $ kubectl apply -f deployment.yaml

    17/05/2021

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  • helm upgrade history

    2 min read

    helm kubernetes history

    When you have an application installed using helm, you can upgrade it by using helm upgrade:

    helm upgrade -f pet2cattle_values.yaml pet2cattle .

    If we need to keep track of all the upgrades we are making to this application, we can rely on helm to keep this data

    01/01/2021

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From pet to cattle
Treat your kubernetes clusters like cattle, not pets