---
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.