OpenvSwitch meshing

See SovereignCloudStack/Docs#98 for my definition of Prio 1-4.

• Prio 1: As a Cloud Operator, I want to know if the OpenvSwitch(**) agent fails to complete its first synchronization iteration without error, because that iteration is vital for the functioning and lack of a successful first iteration causes the below alert and customer visible impact.

  The potential action is to investigate why the first iteration did not complete, resolve the issue and restart the OpenvSwitch agent. If that is not feasible, workload needs to be migrated off the node.

• Prio 3 or higher*: as a Cloud Operator, I want to know if an OpenStack Network on a compute node with the OpenvSwitch agent(**) is lacking any of the following tunnels (VXLAN or VLAN) configured:

  • to a DHCP node with an DHCP instance for any subnet in the network; the corresponding flow rule must allow broadcast traffic.
  • to an L3 node with an L3 router instance with a port in any subnet in the network; the corresponding flow rule must allow broadcast traffic.
  • to another compute node with a compute instance with a port in any subnet in the network; the corresponding flow rule must allow broadcast traffic.

  because lack of those rules can cause loss of DHCP leases, loss of communication between some instances in the same network and loss of internet connectivity for instances.

(*) See footnote in SovereignCloudStack/Docs#98.
(**) I am not sure what SCS intends to use; I am not sure if the same in a different flavour applies for instance to OVN.