This document describes the latest changes, enhancements, known issues, and fixes for Mirantis Container Runtime (MCR) for versions 19.03.x.
Upgrading to the product combination [MKE 3.3.x + MCR 19.03.x + SLES 15 SP3/RHEL 8] can fail due to nodes that are not ready and MKE system containers that do not start. To resolve this problem, refer to Avoid firewall conflicts.
In developing MCR 19.03.x, Mirantis has been transitioning from legacy Docker Hub-issued licenses to JWT licenses, as detailed below:
Versions 19.03.0 to 19.03.10: Docker Hub licenses only
Versions 19.03.11 to 19.03.17: Docker Hub licenses and JWT licenses
Versions 19.03.18 and later: JWT licenses only
Using a JWT license with an MKE instance that manages MCR causes the engine to log error messages in the daemon log file, though MCR does not fail. This applies to MKE 3.4.x versions prior to 3.4.6 and MKE 3.3.x versions prior to 3.3.13.
CentOS 8 entered EOL status as of 31-December-2021. For this reason, Mirantis no longer supports CentOS 8 for all versions of MCR. 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. Refer to the MCR 19.03 Compatibility Matrix for more information.