# kubevirt-launch-failed — One or more VirtualMachineInstances are in the Failed phase **Alert:** `KubeVirtVMLaunchFailing` (critical, 5m) **File:** `platform/kubevirt/alerts.yaml`, group `platform-health.kubevirt` **Expression:** `sum by (namespace) (kubevirt_vmi_phase_count{phase="Failed"}) > 0` ## What this means here A VMI reached the `Failed` phase — a scheduling, launch or qemu failure. The IaaS path is broken for that workload, which is why it is page-worthy even though the VM tier is deliberately **non-gating** (`apps-vms` is `wait: false`, `dependsOn: platform-config`, because a VM's image import and in-guest install are legitimately long-not-Ready). What actually runs here: the `unifi` namespace holds the UniFi VM (rootdisk 40 GiB, Block mode on `longhorn-vm`). **UniFi OS Server is not yet installed in the guest** — that is known, documented state, not a launch failure. **Live note, measured 2026-09-13:** `kubevirt_vmi_phase_count` returned **0 series** on prod. That metric only exists while VMIs do, so this alert is currently evaluating against nothing. Confirm the real state from `kubectl get vmi -A`, not from this alert's silence. (`kubevirt-prometheus-metrics` *is* a live scrape job and `kubevirt_virt_api_ready_status` does publish, so the target is up — see `/runbooks/kubevirt-control-plane`.) ### The three k3s-specific launch failures this platform already hit and fixed Recorded from bring-up, and worth checking against any new VM definition because all three were non-obvious: 1. **`containerDisk` requires the ALPHA `ImageVolume` feature gate**, which is off on k3s. The fix was to switch to a **CDI DataVolume on Longhorn** instead. A VM authored with `containerDisk` will not launch here. 2. **A UEFI image needs `firmware.efi`** set on the VM. Without it, boot fails. 3. **`useEmulation: true` silently forces TCG on KubeVirt v1.9** — it is set to `false` deliberately. A VM that appears to launch but burns a whole core per vCPU is this; it also degrades the Cilium datapath under sustained load. Also recorded: a `virt-handler` certificate error seen during that work was **unrelated and cosmetic** — do not chase it. ## Running the commands in this runbook `kubectl` does not work on the operator workstation. The toolchain lives only in the pinned dev container, and the host's `k3s-oidc` context hangs on a browser prompt once its token expires — that hang is not the cluster being down. Every command below runs as: infra/devcontainer/dev.sh run bash -c 'kubectl --context k3s-prod get nodes' Always pass `--context k3s-prod` explicitly. `dev.sh` merges BOTH clusters into one kubeconfig and picks a current-context per invocation, and **that default has already changed once** — it was k3s-dev until dev was decommissioned on 2026-09-13, and is k3s-prod now. A command that names its context means the same thing next month as it does today; one that relies on the default does not, and the failure is silent (it answers confidently about the other cluster). `CLUSTER=prod infra/devcontainer/dev.sh run kubectl ...` selects it explicitly, and every invocation prints a banner naming the cluster it is about to talk to — read it. Do not run two `dev.sh` invocations at once; they share one container and interfere. USE FULLY-QUALIFIED RESOURCE NAMES, ALWAYS. Three CRDs on this cluster register the kind `Backup`: `longhorn.io/v1beta2`, `postgresql.cnpg.io/v1` and `velero.io/v1`. The bare short name resolves to Longhorn's, which holds zero objects — so `kubectl get backup -A` prints **"No resources found"** on a cluster holding 6 Velero backups and 27 CNPG backups. Verified on prod 2026-09-13. Reading that as "the backups are gone" and acting on it turns a false negative into real data loss. Write `backups.velero.io`, `backups.postgresql.cnpg.io`, `clusters.postgresql.cnpg.io`, `settings.longhorn.io`, `volumes.longhorn.io`, `nodes.longhorn.io`. Mutating kubectl (`apply`, `patch`, `annotate`, `rollout`) and `flux reconcile` are blocked for agents here: every durable change goes through git. **`main` is a protected branch — a direct push is rejected.** A change lands by pushing a branch, opening a PR, and merging it once the gate is green; that merge is the deploy. Where this runbook gives a mutating command it is for an operator, and it says so. ## First commands Which VMI, in which namespace, and what phase: ``` infra/devcontainer/dev.sh run bash -c \ 'kubectl --context k3s-prod get vmi -A -o wide; echo; \ kubectl --context k3s-prod get vm -A -o custom-columns=NS:.metadata.namespace,NAME:.metadata.name,STATUS:.status.printableStatus,READY:.status.ready' ``` The reason — the VMI status conditions and the launcher pod's events are where it is stated: ``` infra/devcontainer/dev.sh run bash -c \ 'kubectl --context k3s-prod -n unifi describe vmi unifi 2>&1 | sed -n "/Status:/,\$p" | head -60' ``` ``` infra/devcontainer/dev.sh run bash -c \ 'kubectl --context k3s-prod -n unifi get pods -l kubevirt.io=virt-launcher -o wide; echo; \ kubectl --context k3s-prod -n unifi describe pod -l kubevirt.io=virt-launcher 2>&1 | sed -n "/Events:/,\$p"' ``` Is the disk there? (A missing or still-importing DataVolume is the most common cause.) ``` infra/devcontainer/dev.sh run bash -c \ 'kubectl --context k3s-prod get datavolumes.cdi.kubevirt.io -A \ -o custom-columns=NS:.metadata.namespace,NAME:.metadata.name,PHASE:.status.phase,PROGRESS:.status.progress; echo; \ kubectl --context k3s-prod get pvc -A | grep -Ei "rootdisk|dv|unifi"' ``` Is nested virtualisation actually available on the node it was scheduled to? ``` ssh k3s-prod-1 'ls -l /dev/kvm; grep -c -E "vmx|svm" /proc/cpuinfo' ``` Is the storage class right for a live-migratable VM? ``` infra/devcontainer/dev.sh run bash -c \ 'kubectl --context k3s-prod get sc; echo; \ kubectl --context k3s-prod -n longhorn-system get volumes.longhorn.io -o custom-columns=NAME:.metadata.name,ROBUST:.status.robustness | grep -v healthy' ``` And whether the KubeVirt control plane can act at all: ``` infra/devcontainer/dev.sh run bash -c 'kubectl --context k3s-prod -n kubevirt get pods' ``` ## Likely causes, most likely first ### 1. The disk is not ready — a CDI import that has not completed or has stalled The VM cannot start without its DataVolume. Go to `/runbooks/cdi-import-stuck`. The specific recorded failure: the **3-replica default class failed the UniFi 60Gi import with insufficient storage / `ReplicaSchedulingFailure`**, which is why a dedicated single-replica **`longhorn-scratch`** class exists and is referenced by the CDI CR's `scratchSpaceStorageClass`. ### 2. The VM is authored in a way k3s does not support The three items above: `containerDisk` without the ALPHA `ImageVolume` gate (use a CDI DataVolume), missing `firmware.efi` for a UEFI image, or `useEmulation: true` forcing TCG. All are git changes to the VM definition. ### 3. The cloud-init payload is too large or corrupted Two precise traps. **KubeVirt caps inline `userData` at 2048 bytes** — the original rich cloud-init exceeded it; `userDataSecretRef` was tried and reverted, and the shipped state is a minimal ~1.1 KB inline payload. And: **`apps-vms` must NOT carry `postBuild.substituteFrom`** — Flux's envsubst rewrote `${...}` inside the cloud-init and corrupted it (commit `da1f833`). *Do not restore substitution there for consistency with the app waves.* If a VM stopped booting right after someone "tidied up" the Flux Kustomizations, this is it. ### 4. It cannot be scheduled No node with room, or a storage constraint. A live-migratable VM needs **`longhorn-vm`**: RWX, **Block mode only** (migratable RWX is a raw block device, not the share-manager/NFS path), annotated `storageclass.kubevirt.io/is-default-virt-class: "true"` — which is *not* the cluster default class. A VM pointed at plain `longhorn` will not live-migrate. ### 5. The CDI importer cannot open the raw Block device `nonroot-devices: true` is set on the k3s servers because the non-root CDI importer must open a raw Block device that Kubernetes never chowns for it (commit `df5979f`). A permission error in the importer on a Block PVC is this. ### 6. The KubeVirt control plane is down Then nothing can launch. `/runbooks/kubevirt-control-plane`. ## When to escalate or stop - **Scope it before escalating.** The VM tier is non-gating and does not affect the container platform. One failed VM is not a platform outage — but the UniFi VM is the home network's controller, so treat that one as user-visible. - **Do not delete the VM or its DataVolume to "start clean".** A 60 GiB re-import is hours of I/O on disks that share a partition with the embedded etcd WAL, and that is the mechanism behind the 2026-09-07 node outage. Fix the definition, not the data. - **Do not set `evictionStrategy: LiveMigrate` cluster-wide.** A blanket setting would **wedge drains** for RWO-disk VMs; it is per-VM on purpose. - **Do not add `postBuild.substituteFrom` to `apps-vms`.** It corrupts cloud-init. - Escalate for anything that needs a fresh image import during a storage incident, and for changes to the k3s server flags (`nonroot-devices`) — those are Ansible/operator work. --- Source of truth: `runbooks/kubevirt-launch-failed.md`. Index: `/runbooks/` Records: `DECISIONS-LOG.md` Session 7 (the three k3s-specific launch failures); commits `da1f833` (cloud-init corrupted by envsubst) and `df5979f` (`nonroot-devices`); the `longhorn-scratch` / UniFi 60Gi import finding.