4.2. Deploying the OVN metadata agent on Compute nodes

The OVN metadata agent is configured in the tripleo-heat-templates/deployment/ovn/ovn-metadata-container-puppet.yaml file and included in the default Compute role through OS::TripleO::Services::OVNMetadataAgent. As such, the OVN metadata agent with default parameters is deployed as part of the OVN deployment. See 4章Deploying OVN with director.

OpenStack guest instances access the Networking metadata service available at the link-local IP address: 169.254.169.254. The neutron-ovn-metadata-agent has access to the host networks where the Compute metadata API exists. Each HAProxy is in a network namespace that is not able to reach the appropriate host network. HaProxy adds the necessary headers to the metadata API request and then forwards the request to the neutron-ovn-metadata-agent over a UNIX domain socket.

The OVN Networking service creates a unique network namespace for each virtual network that enables the metadata service. Each network accessed by the instances on the Compute node has a corresponding metadata namespace (ovnmeta-<net_uuid>).

4.2.1. Troubleshooting Metadata issues

You can use metadata namespaces for troubleshooting to access the local instances on the Compute node. To troubleshoot metadata namespace issues, run the following command as root on the Compute node:

Prerequisites

  • RHOSP deployment with ML2/OVN.

Procedure

  1. Log in as root on the Compute node.
  2. Run the following command, where USER@INSTANCE_IP_ADDRESS is the user name and IP address for the local instance you want to troubleshoot.

    # ip netns exec ovnmeta-fd706b96-a591-409e-83be-33caea824114 ssh USER@INSTANCE_IP_ADDRESS