[Openstack] Can't reach instance's floating IPs because of network infrastructure

Issue

• Can't access/ping a floating IP attached to a VM.
• Can't ping a router's external IP address.

This article is focused on troubleshooting network infrastructure that doesn't belong to OpenStack environment (external routers, switches, etc) to solve communication issues in external networks. The following OpenStack configuration should also be checked:

• Need to confirm that VM's security group is set to allow proper ingress/egress traffic (in out case it is ICMP).
• Need to check if actual network settings match Neutron configuration (for example, VLAN ID, MTU and network address for external network).

This article is written to be a general one and could be used to troubleshoot all kind of routers: legacy, DVRs, OVN, etc. At the same time, additional steps could be required for specific router types.

This article will not allow you to troubleshoot all possible issues, so please contact Red Hat technical support if it wouldn't work for you.