magnum/releasenotes/notes/k8s-fedora-atomic-rolling-upgrade-3d8edcdd91fa1529.yaml
Feilong Wang 05c27f2d73 [k8s][fedora atomic] Rolling upgrade support
Rolling ugprade is an important feature for a managed k8s service,
at this stage, two user cases will be covered:

1. Upgrade base operating system
2. Upgrade k8s version

Known limitation: When doing operating system upgrade, there is no
chance to call kubectl drain to evict pods on that node.

Task: 30185
Story: 2002210

Change-Id: Ibbed59bc135969174a20e5243ff8464908801a23
2019-06-07 14:48:08 +12:00

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YAML

---
features:
- |
Now the fedora atomic Kubernetes driver can support rolling upgrade for k8s
version change or the image change. User can call command
`openstack coe cluster upgrade <cluster ID> <new cluster template ID>` to
upgrade current cluster to the new version defined in the new cluster
template. At this moment, only the image change and the kube_tag change
are supported.
issues:
- |
There is a known issue when doing image(operating system) upgrade for k8s
cluster. Because when doing image change for a server resource, Heat will
trigger the Nova rebuild to rebuild the instnace and there is no chance to
call kubectl drain to drain the node, so there could be a very minior
downtime when doing(starting to do) the rebuild and meanwhile a request
is routed to that node.