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Update blog post headings and add What's Next section

pull/37418/head
Peter Schuurman 2022-11-29 18:33:24 -08:00
parent 8555b53308
commit bd45ab5474
1 changed files with 29 additions and 3 deletions
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content/en/blog/_posts/2022-12-16-statefulset-migration.md
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@ -39,7 +39,7 @@ enables you to retain *at most one* semantics and
[Rolling Update](/docs/tutorials/stateful-application/basic-stateful-set/#rolling-update)
behavior when orchestrating a migration across clusters.
### Why would I want to use this feature?
## Why would I want to use this feature?
Say you're running your StatefulSet in one cluster, and need to migrate it out
to a different cluster. There are many reasons why you would need to do this:
@ -55,12 +55,12 @@ to a different cluster. There are many reasons why you would need to do this:
running an upgraded control plane, and can't handle the risk or downtime of
in-place control plane upgrades.
### How do I use it?
## How do I use it?
Enable the `StatefulSetStartOrdinal` feature gate on a cluster, and create a
StatefulSet with a customized `.spec.ordinals.start`.
### Try it for yourself
## Try it for yourself
In this demo, you'll use the `StatefulSetStartOrdinal` feature to migrate a
StatefulSet from one cluster to another. For this demo, the
@ -139,6 +139,17 @@ kubectl patch sts redis-redis-cluster -p '{"spec": {"replicas": 5}}'
7. Migrate dependencies from `source` to `destination`.
The following commands copy resources from `source` to `destionation`. Details
that are not relevant in `destination` cluster are removed (eg: `uid`,
`resourceVersion`, `status`).
Note: For the PV/PVC, this procedure only works if the underlying storage system
that your `StorageClass` uses can support copying existing PVs into a
new cluster. Storage that is associated with a specific node or topology
may not be supported. Additionally, some storage systems may store
addtional metadata about volumes outside of a PV object, and may require
a more specialized sequence to import a volume.
Source Cluster
```
@ -178,3 +189,18 @@ You should see that the new replica's address has joined the Redis cluster.
a8765caed08f3e185cef22bd09edf409dc2bcc61 10.104.0.19:6379@16379 master - 0 1669766685000 1 connected 0-5460
7743661f60b6b17b5c71d083260419588b4f2451 10.104.0.16:6379@16379 slave 2ce30362c188aabc06f3eee5d92892d95b1da5c3 0 1669766686613 3 connected
```
## What's Next?
This feature provides a building block for a StatefulSet to be split up across
clusters, but does not prescribe the mechanism as to how the StatefulSet should
be migrated. Migration requires coordination of StatefulSet replicas, along with
orchestration of the storage and network layer. This is dependent on the storage
and connectivity requirements of the application installed by the StatefulSet.
Additionally, many StatefulSets are controlled by Operators, which adds another
layer of complexity to migration.
If you're interested in building blocks to make these processes easier, get
involved with
[SIG Multicluster](https://github.com/kubernetes/community/blob/master/sig-multicluster)
to contribute!