How to troubleshoot DHCP issues with VMware Integrated OpenStack 7.x with DVS networking deployments

Products

• VMware
• VMware Integrated OpenStack

Issue/Introduction

Symptoms:

This is only for deployments with DVS-backed networking with VMware Integrated OpenStack 7.x. It does not apply for integrations with NSX.

 

DHCP assignments will be failing. They may exist in OpenStack, but tenant instances will not receive IP address assignments in the guest operating system or vCenter.

Environment

VMware Integrated Openstack 7.x

Resolution

We need to check several items that may be incorrect on the OpenStack side. We'll start with specific networks:

1. Receive the list of network agents with the OpenStack Client: openstack network agent list --network <network uuid>
2. We need the DHCP port IP addresses for the network. This can be collected through the OpenStack horizon GUI or from the OpenStack Client with: openstack port list --device-owner network:dhcp
3. For each DHCP agent we need to perform the following:
   1. SSH into the relevant controller. The VIO controllers can be gathered from the manager with "viocli get controllers". The SSH command is: "viossh <controller UUID>"
   2. Check the networking namespaces for qdhcp-<network ID> with: ip a l
   3. Verify there is a network interface existing with the above command that matches the DHCP ports found in step 2.
   4. Verify the dnsmasq process for the networks are running with: ps guax | grep dnsmasq

If anything from step #3 is missing the DHCP agent pod can be deleted. Upon re-creation all network namespaces will be re-created for networks scheduled to the VIO controller.

 

Once everything is validated OpenStack can safely be ruled out as the issue. The issue exists on the physical network outside of VIO.