Updating a DaemonSet
- Docker & Kubernetes course
- Advanced
- Lesson 23/70
- 4 min
Learn the DaemonSet rolling update strategy.
Updating
DaemonSets have two update strategies:
RollingUpdate(default): nodes are updated one by one;maxUnavailablesets how many nodes may be without the agent at once.OnDelete: nothing happens when the template changes; when a pod is deleted by hand, the new one is created with the new template. It's used for controlled updates of critical components like network plugins.
spec:
updateStrategy:
type: RollingUpdate
rollingUpdate:
maxUnavailable: 1
kubectl set image ds/node-exporter exporter=prom/node-exporter:v1.8.3 -n izleme
kubectl rollout status ds/node-exporter -n izlemeHistory and rollback
A DaemonSet also keeps a rollout history and is rolled back with the same commands as a Deployment:
$ kubectl rollout history ds/node-exporter -n izleme
REVISION CHANGE-CAUSE
1 <none>
2 <none>
$ kubectl rollout undo ds/node-exporter -n izleme
daemonset.apps/node-exporter rolled backPractice Update the agent
Write three commands: set the image of the exporter container in the node-exporter DaemonSet in the izleme namespace to prom/node-exporter:v1.8.3; wait for the rollout to finish; show the history.
Starter code
# buraya yazSample solution
kubectl set image ds/node-exporter exporter=prom/node-exporter:v1.8.3 -n izleme
kubectl rollout status ds/node-exporter -n izleme
kubectl rollout history ds/node-exporter -n izlemeExpected output
daemonset.apps/node-exporter image updated Waiting for daemon set "node-exporter" rollout to finish: 1 out of 3 new pods have been updated... daemon set "node-exporter" successfully rolled out REVISION CHANGE-CAUSE 1 <none> 2 <none>
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Under the OnDelete strategy, what happens when the image is changed?
- All update immediately
- The DaemonSet is deleted
- It errors
- Running pods don't change; ones deleted by hand are created with the new image Correct answer
Explanation: The operator decides the timing and order of the update.
2 Set the update to be triggered by hand.
Question
spec:
updateStrategy:
type: ____
Answer
spec:
updateStrategy:
type: OnDeleteExplanation: OnDelete updates when a pod is deleted.
3 Match.
| Term | Meaning |
|---|---|
RollingUpdate |
Update node by node |
OnDelete |
Update when deleted by hand |
maxUnavailable |
Limit on agentless nodes |
rollout undo ds/ |
Roll back |