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We were facing an issue when extending the Openstack public network range by adding a new subnet, by looking the comments of that launchpad bug: https://bugs.launchpad.net/neutron/+bug/1605343 Seems like the way to do it is to add a newer subnet, but doing so we encounter the following issue: When using Openstack with OVN networking and Octavia LBaaS, creating routers with different external gateway subnets (e.g.. public-subnet and public-subnet-2) causes load balancer VIPs to become unreachable across subnets from VMs on the same public-subnet Reproduction Steps: 1) Create two public subnets (public-subnet, public-subnet-2) on the same external network 2) Create two routers router1 with external gateway set to public-subnet-2 router2 with external gateway set to public-subnet 3) Attach internal networks (private, private-2) to each router 4) Launch VMs in each subnet and deploy web servers 5) Create two Octavia load balancers: subnet1_lb1 in private network subnet2_lb1 in private-2 network Assign floating IPs to the VIP ports of both load balancers 6) From each VM, try accessing subnet1_lb1 and subnet2_lb1 Observed Behavior: From subnet1_node1 (172.24.4.100) behind router R1 (172.24.5.X subnet) we are able to reach the Octavia LB subnet1_lb1 (172.24.4.200) ✅ From subnet1_node1 (172.24.4.100) behind router R1 (172.24.5.X subnet) we are not able to reach the Octavia LB subnet1_lb2 (172.24.5.200) ❌ From subnet2_node1 (172.24.5.100) behind router R2 (172.24.4.X subnet) we are able to reach the Octavia LB subnet2_lb1 (172.24.5.200) ✅ From subnet2_node1 (172.24.5.100) behind router R2 (172.24.4.X subnet) we are not able to reach the Octavia LB subnet1_lb1 (172.24.4.200) ❌ If we put those in a matrix: Source VM Router (Gateway Subnet) Target LB VIP Expected Observed Result subnet1_node1 R1 (public-subnet-2 / 172.24.5.X) subnet1_lb1 (172.24.4.200) Reachable 200. ✅ subnet1_node1 R1 (public-subnet-2 / 172.24.5.X) subnet2_lb1 (172.24.5.200) Reachable Timeout ❌ subnet2_node1 R2 (public-subnet / 172.24.4.X) subnet2_lb1 (172.24.5.200) Reachable 200. ✅ subnet2_node1 R2 (public-subnet / 172.24.4.X). subnet1_lb1 (172.24.4.200) Reachable Timeout ❌ We clearly see that a VM from a different subnet tries to reach a loadbalancer via the LB floating IP, the LB is not reachable if the router (connecting the LB to the public network) external IP is in a different range than the LB floating IP. Expected Behavior: All VMs, regardless of which subnet/router they are connected to, should be able to reach any VIP exposed via floating IP Environment: OpenStack with OVN (replicable on latest version with Devstack) Below i'll attach the scripts to replicate it on a freshly created Devstack instance Feel free to reach out for any further detail ** Affects: neutron Importance: Undecided Status: New -- Floating IPs attached to Octavia LB VIPs are not reachable across routers using different external subnets (OVN + Octavia) https://bugs.launchpad.net/bugs/2110225 You received this bug notification because you are a member of Yahoo! Engineering Team, which is subscribed to neutron. -- Mailing list: https://launchpad.net/~yahoo-eng-team Post to : yahoo-eng-team@lists.launchpad.net Unsubscribe : https://launchpad.net/~yahoo-eng-team More help : https://help.launchpad.net/ListHelp
