Video by CNCF [Cloud Native Computing Foundation] via YouTube
Running virtual machines on Kubernetes with KubeVirt works well until you need to live-migrate one. When a VM moves to another node, its networking is what breaks first: the IP address can change, established TCP sessions drop, and routes have to reconverge before traffic finds the VM again. This session shows how Calico handles all three so a VM can move between nodes while keeping its address and staying online.
We’ll start with KubeVirt’s networking modes and make the case for bridge mode, where the virt-launcher pod IP is the VM IP. That’s the foundation everything else builds on. From there, we cover the three parts of the problem. IP persistence is where Calico’s IPAM holds the VM’s address steady across the move. TCP session continuity is where an open connection survives the handover without reconnecting. Route convergence is where Felix and BGP pick up the gratuitous ARP and reprogram routes to the new node.
Each part is paired with a live demo on a multi-node Calico cluster, so you can watch the IP stay put, the TCP session hold, and cutover downtime stay near zero.
By the end, you’ll understand why live migration breaks VM networking on Kubernetes, and how Calico keeps the address while dropping the downtime.