Hybrid Cluster

A Hybrid Cluster occurs when the hosts with a worker function (AIO controllers and worker nodes) are split between two groups, one running StarlingX OpenStack for hosting VM payloads and the other for hosting containerized payloads.

The host labels are used to define each worker function on the Hybrid Cluster setup. For example, a standard configuration (2 controllers and 2 computes) can be split into (2 controllers, 1 openstack-compute and 1 kubernetes-worker).

Limitations

• Worker function on AIO controllers MUST both be either Kubernetes or OpenStack.

  • Hybrid Cluster does not apply to AIO-SX or AIO-DX setups.

• A worker must have only one function, either it is OpenStack compute or k8s-only worker, never both at the same time.

  • The sriov and sriovdp labels cannot coexist on the same host, in order to prevent the SR-IOV device plugin from conflicting with the OpenStack SR-IOV driver.

  • No host will assign VMs and application containers to application cores at the same time.

• Standard Controllers cannot have openstack-compute-node label; only AIO Controllers can have openstack-compute-node label.

• Taints must be added to OpenStack compute hosts (i.e. worker nodes or AIO-Controller nodes with the openstack-compute-node label) to prevent end users’ hosted containerized workloads/pods from being scheduled on OpenStack compute hosts.