Release Notes
Considerations
Upgrading MKE 3.6.0 - 3.6.4 to a later MKE version can result in
ucp-pausecontainers not carrying forward to the later version.A limitation in MKE 3.6.2 and MKE 3.6.3 can cause issues in clusters that deploy more than 120 nodes.
If you plan to run a cluster with more than 120 nodes, Mirantis strongly recommends that you upgrade to MKE 3.6.4. If, however, it is imperative that you run one of the affected MKE versions with 121+ nodes, contact Mirantis support to secure a workaround.
As MKE 3.6.0 runs etcd 3.4.16, upgrading to it from MKE 3.5.6 or later (which run etcd 3.5.5) will fail. As such, it is necessary to upgrade instead to MKE 3.6.1 or later.
The etcd component, by design, will not accept a downgrade of itself.
MKE 3.6.0 requires MCR 20.10.13 or later, which you must install or upgrade to prior to installing or upgrading to MKE 3.6.0.
Upgrading from one MKE minor version to another minor version can result in the downgrading of MKE middleware components. For more information, refer to the middleware versioning tables in the release notes of both the source and target MKE versions.
CentOS 8 entered EOL status as of 31-December-2021. For this reason, Mirantis no longer supports CentOS 8 for all versions of MKE. We encourage customers who are using CentOS 8 to migrate onto any one of the supported operating systems, as further bug fixes will not be forthcoming.
Custom log drivers are no longer supported, beginning with MKE 3.6.0. This is due to the transition from Dockershim over to cri-dockerd.
In MKE 3.6.1 - 3.6.7, performance issues may occur with both cri-dockerd and dockerd due to the manner in which cri-dockerd handles container and ImageFSInfo statistics.