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Update task for DaemonSet history and rollback (#4098)

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* Update task for DaemonSet history and rollback

Also remove mentions of templateGeneration field because it's deprecated

* Address comments
This commit is contained in:
Janet Kuo
2017-06-22 10:56:52 -07:00
committed by Andrew Chen
parent 43b9e97774
commit 9f6d8f4788
3 changed files with 168 additions and 39 deletions
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docs/tasks/manage-daemon/update-daemon-set.md
+13 -39
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@@ -33,46 +33,18 @@ DaemonSet has two update strategy types :
DaemonSet template, old DaemonSet pods will be killed, and new DaemonSet pods
will be created automatically, in a controlled fashion.
## Limitations
* DaemonSet rollout history is not supported yet.
* DaemonSet rollback is not directly supported in `kubectl` yet. You can rollback
by updating DaemonSet template to match the previous version.
## Caveat: Updating DaemonSet created from Kubernetes version 1.5 or before
If you try to rolling update a DaemonSet that was created from Kubernetes
If you try a rolling update on a DaemonSet that was created from Kubernetes
version 1.5 or before, a rollout will be triggered when you *first* change the
DaemonSet update strategy to `RollingUpdate`, even when DaemonSet template isn't
modified. All existing DaemonSet pods will be restarted.
DaemonSet update strategy to `RollingUpdate`, no matter if DaemonSet template is
modified or not. If the DaemonSet template is not changed, all existing DaemonSet
pods will be restarted (deleted and created).
To avoid this restart, first find the DaemonSet's current
`.spec.templateGeneration`:
Therefore, make sure you want to trigger a rollout before you first switch the
strategy to `RollingUpdate`.
```shell{% raw %}
kubectl get ds/<daemonset-name> -o go-template='{{.spec.templateGeneration}}{{"\n"}}'
{% endraw %}```
The output should be a number *N*. If the output shows `<no value>`, N = 0.
Then, simply label the existing DaemonSet pods with `pod-template-generation=<N>`
before changing DaemonSet `.spec.updateStrategy` to `RollingUpdate`:
```shell
# Replace N with DaemonSet `.spec.templateGeneration`
# Only run this on pods created from current DaemonSet template
kubectl label pods -l <daemonset-selector-key>=<daemonset-selector-value> pod-template-generation=<N>
```
This tells the DaemonSet that the labeled DaemonSet pods are created from current
DaemonSet template. Therefore, you should only run this command to existing DaemonSet
pods that are generated from current DaemonSet template.
Note that you only need to do this when you first change the update strategy of
a DaemonSet created from Kubernetes version 1.5 or before to `RollingUpdate`,
but don't want to update its template and start a new rollout yet.
## Setting DaemonSet update strategy for rolling update
## Performing a Rolling Update
To enable the rolling update feature of a DaemonSet, you must set its
`.spec.updateStrategy.type` to `RollingUpdate`.
@@ -87,15 +59,15 @@ First, check the update strategy of your DaemonSet, and make sure it's set to
RollingUpdate:
```shell{% raw %}
kubectl get ds/<daemonset-name> -o go-template='{{.spec.updateStrategy.type}}{{"\n"}}'{% endraw %}
```
kubectl get ds/<daemonset-name> -o go-template='{{.spec.updateStrategy.type}}{{"\n"}}'
``` {% endraw %}
If you haven't created the DaemonSet in the system, check your DaemonSet
manifest with the following command instead:
```shell{% raw %}
kubectl create -f ds.yaml --dry-run -o go-template='{{.spec.updateStrategy.type}}{{"\n"}}'
{% endraw %}```
``` {% endraw %}
The output from both commands should be:
@@ -224,7 +196,9 @@ progress.
{% capture whatsnext %}
*TODO: Link to "Task: Creating a DaemonSet to adopt existing DaemonSet pods"*
* See [Task: Performing a rollback on a
DaemonSet](/docs/tasks/manage-daemon/rollback-daemon-set/)
* *TODO: Link to "Task: Creating a DaemonSet to adopt existing DaemonSet pods"*
{% endcapture %}