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Aleksei Sviridkin
12c3cd03f8
## What this PR does Adds `docs/vm-external-vlan.md`, a guide for attaching a `vm-instance` VM directly to an external, physically-routed VLAN via a Linux bridge and a `bridge`-type NetworkAttachmentDefinition. The documented VM networking story is overlay-only (pod network + KubeOVN VPC subnets). Attaching a VM to a real VLAN — so it shares a broadcast domain with external hardware and takes an address from that VLAN's subnet — is undocumented, and the obvious `macvlan` approach silently fails with KubeVirt's default bridge binding: macvlan demultiplexes ingress by the child interface's MAC while bridge binding puts the guest's own MAC on the wire, so gateway replies reach the parent interface and are dropped before the guest. The working recipe is a Linux bridge + `bridge` CNI NAD. The guide covers why bridge and not macvlan, the host bridge, the NAD (one per tenant namespace), assigning a static guest address through cloud-init (the chart has no `networkData`), the always-present dual-homed pod NIC, and the post-recreate ARP staleness from KubeVirt regenerating the guest MAC. Docs-only; no chart or manifest changes. The recipe depends on the `bridge` CNI plugin being present in `/opt/cni/bin`; #3195 makes Cozystack's multus package stage the reference plugins there. ### Screenshots N/A — no UI changes. ### Release note ```release-note docs(vm-instance): add a guide for attaching a VM to an external VLAN via a Linux bridge and a bridge-type NetworkAttachmentDefinition ``` <!-- This is an auto-generated comment: release notes by coderabbit.ai --> ## Summary by CodeRabbit * **Documentation** * Added a new guide for connecting a `vm-instance` directly to an externally routed VLAN. * Includes setup steps for creating a bridged VLAN interface, defining a network attachment, and configuring the VM with a static IP. * Notes important networking caveats such as dual-homing behavior, MAC changes after recreation, and host-to-VM connectivity requirements. <!-- end of auto-generated comment: release notes by coderabbit.ai -->