Helm controller

Helm controller

Helm controller is used by Mirantis Container Cloud to handle management, regional, and managed clusters core addons such as StackLight and the application addons such as the OpenStack components.

Helm controller runs in the same pod as the Tiller process. The Tiller gRPC endpoint is not accessible outside the pod. The pod is created using StatefulSet inside a cluster by LCM controller once the cluster contains at least one manager and worker node.

The Helm release information is stored in the KaaSRelease object for the management and regional clusters and in the ClusterRelease object for all types of the Container Cloud clusters. These objects are used by the Container Cloud provider. The Container Cloud provider uses the information from the ClusterRelease object together with the Container Cloud API Cluster spec. In Cluster spec, the operator can specify the Helm release name and charts to use. By combining the information from the Cluster providerSpec parameter and its ClusterRelease object, the cluster actuator generates the LCMCluster objects. These objects are further handled by LCM controller and the HelmBundle object handled by Helm controller. HelmBundle must have the same name as the LCMCluster object for the cluster that HelmBundle applies to.

Although a cluster actuator can only create a single HelmBundle per cluster, Helm controller can handle multiple HelmBundle objects per cluster.

Helm controller handles the HelmBundle objects and reconciles them with the Tiller state in its cluster.

Helm controller can also be used by the management cluster with corresponding HelmBundle objects created as part of the initial management cluster setup.