# Session: CAPMOX against a two-node PVE cluster

**Date:** 2026-09-29 23:11 CEST

## Question

`pv1-1` became the PVE cluster `homelab`, and a second node `pv1-2` joined it. Does the CAPI/CAPMOX
configuration need changes to work against the cluster?

## What was checked

- PVE API (read-only GETs with the `capmox@pve!capi` token, 2026-09-29): `/cluster/status`,
  `/nodes`, `/storage`, `/nodes/<n>/network`, `/nodes/<n>/storage`, `/cluster/resources`,
  `/access/acl`.
- CAPMOX v0.9.1 source (Go proxy zip): scheduler, clone path, template lookup,
  `templates/cluster-template.yaml`.
- PVE `qemu-server` `PVE/API2/Qemu.pm` (HEAD, not pinned to a PVE release): the clone target check.

## Findings

PVE state:

| Item | pv1-1 | pv1-2 |
| --- | --- | --- |
| IP | 192.168.0.8 | 192.168.0.10 |
| CPU / RAM | 16 / 29.2 GiB | 12 / 40.9 GiB |
| `vmbr0` VLAN-aware | yes | **no** |
| `local-lvm` | local LVM-thin | local LVM-thin (not shared) |
| Templates | 101 `ubuntu-2404-kube-v1.35.9`, 9000, 9001 | none |

- Storage definitions (`local`, `local-lvm`, `proxy-seeds`) are cluster-wide without a `nodes`
  restriction, but none of them is shared.
- The `capmox@pve` ACLs (`/`, `/storage`, `/sdn/zones/localnetwork`) are cluster-wide, so they
  cover `pv1-2` as well. There are no SDN zones.

CAPMOX v0.9.1:

- **Node choice.** If the ProxmoxMachine has its own `allowedNodes`, that list replaces the
  ProxmoxCluster's (`internal/service/scheduler/vmscheduler.go:52-62`).
  - The scheduler balances by how many machines of this cluster are already on each node
    (`status.nodeLocations`), and only picks a node where the requested memory fits
    (`vmscheduler.go:75-119`).
  - `memoryAdjustment` is applied per node, against that node's own total memory.
  - With empty `allowedNodes` the scheduler isn't called and the VM clones on the source node
    (`internal/service/vmservice/vm.go:477`).
- **Clone.** `target` goes to the PVE clone call as-is (`pkg/proxmox/goproxmox/api_client.go:84-95`).
  - PVE refuses a cross-node clone when any source disk is on non-shared storage:
    `can't clone VM to node '<target>' (VM uses local storage)`.
  - Setting `full: true` or `storage` does not change that.
  - v0.9.1 has no `localStorage` option.
- **`templateSelector`** searches the whole PVE cluster and needs exactly one match
  (`api_client.go:149-212`). "One template per node with the same tags" fails with
  `found 2 VM templates`.
- **API URL and credentials.** Everything goes through one API URL; nothing in the credentials
  names a node.
  - Cross-node requests should be forwarded by PVE (standard PVE behaviour, not checked in code).
  - `192.168.0.8` is `pv1-1`, so a down `pv1-1` also means no API for CAPMOX.
- **Bridge.** `bridge`/`vlan` are written into `netX` without any check (`vm.go:338`).

Conclusion:

- Nothing has to change for the current setup to keep working. `lab1` pins `allowedNodes: [pv1-1]`
  and `sourceNode: pv1-1`, which is decision #7.
- Using `pv1-2` requires two things:
  1. Make `vmbr0` on `pv1-2` VLAN-aware and trunk VLAN 4 on its switch port.
  2. Either put a template copy on `pv1-2`, or add shared storage.
- With a template copy per node:
  - Workers get one ProxmoxMachineTemplate and one MachineDeployment per PVE node, each with
    `sourceNode`, `templateID` (the node's own VMID) and `allowedNodes: [<node>]`. For
    cluster-autoscaler that is one node group per PVE node.
  - KubeadmControlPlane takes a single infrastructureRef, so the control plane stays on one node.

## Open questions

- How to get the template onto `pv1-2`: a second image-builder run (`PROXMOX_NODE=pv1-2`), or
  `qm clone` + `qm migrate` / vzdump-restore? The image-builder run is reproducible; the copy is
  faster.
- Is shared storage (NFS) worth adding instead? It gives one MachineDeployment spread over both
  nodes, and the control plane can use both nodes too.
- Behaviour when a cross-node clone fails: the scheduler may keep picking the same node. This is
  inferred from the code, not tested.

## Follow-ups

- The owner chose: no shared storage for now; copy template 101 to `pv1-2` as 9101; keep
  `lab1-workers` and add `lab1-workers-pv1-2`. Plan:
  [2026-09-29-2315-pv1-2-workers](../plans/2026-09-29-2315-pv1-2-workers.md). It covers the bridge
  fix, the template copy, the second MD, the CA limits and a decision row superseding #7.
- Update the "Lab facts" in CLAUDE.md/AGENTS.md: PVE cluster `homelab`, `pv1-2` at 192.168.0.10.

## Outcome (2026-09-30)

Done as planned, and confirmed on the lab:
- template 9101 on `pv1-2`;
- MDs `lab1-workers-pv1-1` (max 6) + `lab1-workers-pv1-2` (max 12);
- a balanced scale-up of 4 + 4 across both PVE nodes.

Two cluster-autoscaler findings from the scale test (no balancing, and throttling from uncached
discovery) led to decision #19. Details are in the
[execution log](../plans-executions/2026-09-29-2315-pv1-2-workers.md).