Automatic upgrade of a host operating system¶
To keep operating system on a bare metal host up to date with the latest security updates, the operating system requires periodic software packages upgrade that may or may not require the host reboot.
Mirantis Container Cloud uses life cycle management tools to update the operating system packages on the bare metal hosts. Container Cloud may also trigger restart of bare metal hosts to apply the updates.
In the management cluster of Container Cloud, software package upgrade and host restart is applied automatically when a new Container Cloud version with available kernel or software packages upgrade is released.
In managed clusters, package upgrade and host restart is applied as part of usual cluster upgrade using the Update cluster option in the Container Cloud web UI.
Operating system upgrade and host restart are applied to cluster nodes one by one. If Ceph is installed in the cluster, the Container Cloud orchestration securely pauses the Ceph OSDs on the node before restart. This allows avoiding degradation of the storage service.
Depending on the cluster configuration, applying security updates and host restart can increase the update time for each node to up to 1 hour.
Cluster nodes are updated one by one. Therefore, for large clusters, the update may take several days to complete.