Mirantis Container Cloud (MCC) becomes part of Mirantis OpenStack for Kubernetes (MOSK)!

Starting with MOSK 25.2, the MOSK documentation set covers all product layers, including MOSK management (formerly Container Cloud). This means everything you need is in one place. Some legacy names may remain in the code and documentation and will be updated in future releases. The separate Container Cloud documentation site will be retired, so please update your bookmarks for continued easy access to the latest content.

Node maintenance API objects

The node maintenance API consists of the following objects:

  • Cluster level:

    • ClusterWorkloadLock

    • ClusterMaintenanceRequest

  • Node level:

    • NodeWorkloadLock

    • NodeMaintenanceRequest

WorkloadLock objects

The WorkloadLock objects are created by each Application Controller. These objects prevent LCM from performing any changes on the cluster or node level while the lock is in the active state. The inactive state of the lock means that the Application Controller has finished its work and the LCM can proceed with the node or cluster maintenance.

ClusterWorkloadLock object example configuration
apiVersion: lcm.mirantis.com/v1alpha1
kind: ClusterWorkloadLock
metadata:
  name: cluster-1-openstack
spec:
  controllerName: openstack
status:
  state: active # inactive;active;failed (default: active)
  errorMessage: ""
  release: "6.16.0+21.3"
NodeWorkloadLock object example configuration
apiVersion: lcm.mirantis.com/v1alpha1
kind: NodeWorkloadLock
metadata:
  name: node-1-openstack
spec:
  nodeName: node-1
  controllerName: openstack
status:
  state: active # inactive;active;failed (default: active)
  errorMessage: ""
  release: "6.16.0+21.3"

MaintenanceRequest objects

The MaintenanceRequest objects are created by LCM. These objects notify Application Controllers about the upcoming maintenance of a cluster or a specific node.

ClusterMaintenanceRequest object example configuration
apiVersion: lcm.mirantis.com/v1alpha1
kind: ClusterMaintenanceRequest
metadata:
  name: cluster-1
spec:
  scope: drain # drain;os
NodeMaintenanceRequest object example configuration
 apiVersion: lcm.mirantis.com/v1alpha1
 kind: NodeMaintenanceRequest
 metadata:
   name: node-1
 spec:
   nodeName: node-1
   scope: drain # drain;os

The scope parameter in the object specification defines the impact on the MOSK cluster or node. The list of the available options include:

  • drain

    A regular cluster update. Each node in the cluster goes over a drain procedure. No node reboot takes place, a maximum impact includes restart of services on the node including Docker, which causes the restart of all containers present in the cluster.

  • os

    A node might be rebooted during the update. Triggers the workload evacuation by the OpenStack Controller (Rockoon).

When the MaintenanceRequest object is created, an Application Controller executes a handler to prepare workloads for maintenance and put appropriate WorkloadLock objects into the inactive state.

When maintenance is over, LCM removes MaintenanceRequest objects, and the Application Controllers move their WorkloadLocks objects into the active state.