March 17, 2020
This advisory was first communicated by email, on the date mentioned above, to all Rancher customers with a then active support subscription.
Dear Rancher 2.x user,
This is an operational advisory from Rancher Support that is addressed to users of Rancher 2.x who run Windows clusters.
With their update on Feb 11, 2020, Microsoft requires container images to be on the same Windows server version as their host.
Refer to this Windows KB Article: https://support.microsoft.com/en-us/help/4542617/you-might-encounter-issues-when-using-windows-server-containers-with-t
When shipping v2.4.0 and v2.3.6, Rancher will be packaging our agents with the latest Windows server core version, which requires users to upgrade their nodes to the latest Windows server version.
Here’s the associated GH issue with our findings and testings:
If you are running Windows clusters and looking to upgrade Rancher, you will need to upgrade your nodes to the latest Windows server version before upgrading Rancher.
In order to upgrade your Windows worker nodes, you can add the correct Windows server nodes into your cluster(s) before removing the old Windows server nodes.
How to recover in the event of a failure to upgrade Windows Server prior to the Rancher upgrade?
In the event of Rancher getting upgraded before upgrading the Windows server version in your cluster, please know that the Windows cluster will fail due to the Rancher agent not being compatible with the old Windows server nodes.
This can be fixed by adding correct Windows server nodes into your cluster before removing the old Windows server nodes.
Simply submit a request via this portal referencing this article and we will track and respond to your question as a Support Ticket.
Rancher Support Team