KVM/libvirt provider: proxies as VMs on your own hypervisors #5

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kacerr merged 28 commits from feat/kvm-provider into main 2026-09-11 17:02:33 +02:00
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Adds a kvm provider type: Managed proxies as VMs on your own libvirt/KVM hosts, reached over SSH with the libvirt unix socket forwarded through the connection (pure Go, nothing to expose on the hypervisors beyond sshd). One provider instance can span several hosts, selected by placement.zone.

What it does

  • Base images (images: map or a direct URL in placement.image) are downloaded by the operator into each host's storage pool on first use, sha256-verified when configured, and cached as base-<key>.qcow2.
  • Each Proxy becomes a qcow2 overlay on the base, a NoCloud seed ISO with the Proxy's cloud-config, and a q35 UEFI domain on a bridge with a serial console and the guest-agent channel. Orphan GC recognises its VMs through libvirt <metadata>.
  • IP discovery via the QEMU guest agent, with the host ARP table as fallback. The agent bootstrap is merged into every Proxy's cloud-config (packages + runcmd) because cloud-init's default merger drops vendor-data keys the user-data also defines.
  • Every libvirt RPC is traced at --zap-log-level=debug (rpc=virDomainCreate, identifiers, duration, libvirtError on failure); level 2 adds XML, metadata and addresses. Cloud-init content is never logged.

Validated

  • make test-integration-kvm against a libvirt 11.6 / QEMU 10.1 host (Debian 13, UEFI): full Create → IP → ListByTag → Delete lifecycle.
  • In-cluster (kind): two Proxies with real cloud-configs reach Ready/healthy in about two minutes; 204 through squid from the LAN.

Found only on the real host and fixed here: disks referenced by host path for AppArmor-confined QEMU; metadata parsed by local name; UEFI by default because Debian 13 hangs in GRUB under SeaBIOS headless (Debian bug #1111240); writable /tmp for the seed writer under a read-only rootfs; guest-agent merge described above.

Docs: docs/kvm-provider.md (prerequisites, config reference, what lands on the host, known gaps, testing). Plan and execution log under docs/plans*/2026-09-04-1404-kvm-provider.md.

🤖 Generated with Claude Code

Adds a `kvm` provider type: Managed proxies as VMs on your own libvirt/KVM hosts, reached over SSH with the libvirt unix socket forwarded through the connection (pure Go, nothing to expose on the hypervisors beyond sshd). One provider instance can span several hosts, selected by `placement.zone`. **What it does** - Base images (`images:` map or a direct URL in `placement.image`) are downloaded by the operator into each host's storage pool on first use, sha256-verified when configured, and cached as `base-<key>.qcow2`. - Each Proxy becomes a qcow2 overlay on the base, a NoCloud seed ISO with the Proxy's cloud-config, and a q35 UEFI domain on a bridge with a serial console and the guest-agent channel. Orphan GC recognises its VMs through libvirt `<metadata>`. - IP discovery via the QEMU guest agent, with the host ARP table as fallback. The agent bootstrap is merged into every Proxy's cloud-config (`packages` + `runcmd`) because cloud-init's default merger drops vendor-data keys the user-data also defines. - Every libvirt RPC is traced at `--zap-log-level=debug` (`rpc=virDomainCreate`, identifiers, duration, `libvirtError` on failure); level 2 adds XML, metadata and addresses. Cloud-init content is never logged. **Validated** - `make test-integration-kvm` against a libvirt 11.6 / QEMU 10.1 host (Debian 13, UEFI): full Create → IP → ListByTag → Delete lifecycle. - In-cluster (kind): two Proxies with real cloud-configs reach `Ready`/healthy in about two minutes; 204 through squid from the LAN. **Found only on the real host and fixed here**: disks referenced by host path for AppArmor-confined QEMU; metadata parsed by local name; UEFI by default because Debian 13 hangs in GRUB under SeaBIOS headless (Debian bug #1111240); writable `/tmp` for the seed writer under a read-only rootfs; guest-agent merge described above. Docs: `docs/kvm-provider.md` (prerequisites, config reference, what lands on the host, known gaps, testing). Plan and execution log under `docs/plans*/2026-09-04-1404-kvm-provider.md`. 🤖 Generated with [Claude Code](https://claude.com/claude-code)
kacerr added 19 commits 2026-09-10 23:40:02 +02:00
Design for a kvm provider type: SSH-forwarded libvirt socket, multi-host
config with placement.zone selecting the host, bridged networking with
ARP/guest-agent IP discovery, operator-fetched distro cloud images cached
in the host's storage pool, and a NoCloud seed ISO carrying the CRD's
cloud-init user-data.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Adds the kvm block to the providers config (SSH access, images map,
machine-type profiles, hosts list) with validation and table tests.
validate() now rejects mismatched type-specific blocks generically via
setBlocks() instead of pairwise checks.

Step 1 of docs/plans/2026-09-04-1404-kvm-provider.md.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Introduces internal/provider/kvm with the side-effect-free pieces of the
provider: providerID format/parse, the namespaced <metadata> element that
carries the GC contract, q35 domain XML over pool volumes, volume XML for
overlays and raw seeds, the NoCloud seed ISO built with kdomanski/iso9660,
and config defaults. All unit-tested.

Step 2 of docs/plans/2026-09-04-1404-kvm-provider.md.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Per-host connection pool over SSH with the libvirt unix socket forwarded
through the session, lazy dial and redial after disconnect, context
cancellation for go-libvirt's context-less RPCs, handshake deadline and
SSH keepalives. Error classification onto the provider taxonomy. Tested
with a fake dialer and an in-process SSH server that forwards unix sockets.

Step 3 of docs/plans/2026-09-04-1404-kvm-provider.md.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
resolveImage maps placement.image to a configured key or URL; imageCache
streams the download through StorageVolUpload with a sha256 tee, writes
a marker volume when the upload is verified, and re-fetches when the
marker is missing or the configured checksum changed. Errors carry
taxonomy sentinels that classify now honours. Adds the in-memory fake
libvirt API used from here on.

Step 3b of docs/plans/2026-09-04-1404-kvm-provider.md.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Create looks the domain up first and only starts it when it exists;
otherwise it caches the image, reuses or creates the overlay, rebuilds
the seed ISO unconditionally (a cancelled upload can leave a truncated
seed that no later attempt would repair), defines and starts the domain.
Get maps libvirt state plus the first routable IPv4 from ARP or the
guest agent onto the provider states. Delete destroys, undefines and
removes the per-VM volumes by name, tolerating every already-gone case.
ListByTag keeps managed domains across all hosts, skipping domains it
cannot read and failing the sweep only for an unreachable host.

Also corrects the Step 2 seed determinism test: the iso9660 writer
stamps the build time into the volume descriptor, so builds differ by a
few bytes; the test now compares label, files and size.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Behind -tags=integration and self-skipping unless KVM_TEST_* names a
host: one sequential lifecycle (image fetch, Create, idempotent
re-Create, Running with IP, ListByTag, Delete, pool state afterwards),
driven through the provider directly so it needs no Step 5 wiring.
Adds `make test-integration-kvm` and documents the run and the
deviation from the testcontainers convention in docs/testing.md.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Registers "kvm" in the provider builtins, mounts an optional kvm-ssh
Secret at /etc/proxy-operator/kvm, adds a kvm-home providers-config
sample and a proxy_kvm.yaml Proxy sample, documents the provider in
docs/kvm-provider.md (prerequisites, config reference, image cache and
its do-not-replace-in-use rule, known gaps), and updates the README
and architecture provider sections and decision log.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
The first run against a real hypervisor (beelink, Ubuntu, libvirt 11.6)
failed at DomainCreate with "Could not open base image: Permission denied"
even with correct DAC ownership. libvirt's virt-aa-helper only grants QEMU
access to disk sources that carry a path; the <disk type="volume"> form
chosen in Step 2 gives it pool and volume names instead, so the overlay and
its backing image get no AppArmor rule on any stock Debian/Ubuntu host.

buildDomainXML now takes DiskPath/SeedPath and emits type="file" disks.
ensureOverlay and writeSeed return the volume handles and Create resolves
both paths with StorageVolGetPath before defining the domain. The domain
XML test rejects any volume/pool reference so this cannot drift back; the
Create test asserts the sources equal the paths libvirt reported.

Execution log: Step 2 note marked reverted, Step 7 entry opened with the
two failed runs and the diagnosis.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Run 3 on the real host got past Create and failed in Get: libvirt 11.6
selects the <instance> element by our URI in DomainGetMetadata but hands
it back with no namespace declaration, and the parser required the URI
on the element. The lookup already guarantees the namespace, so match on
the local name only. The fake now strips the declaration the way libvirt
does, and a new test pins the bare form. Execution log updated.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
A tracingAPI decorator wraps the 17-method libvirt seam and logs one
"libvirt call" line per RPC after it returns: method, the identifiers it
was given, curated results, duration, and on failure the error with its
libvirt code, name and message. At V(2) the same line carries the domain
and volume XML, metadata and addresses; upload bodies are never logged.
The pool applies it in call() when V(1) is enabled and logs connect,
dial-failure and drop events, taking the caller's logger explicitly like
every other helper in the package.

The integration test installs a testr logger at KVM_TEST_LOG_LEVEL
(default 1) so the trace interleaves with t.Log output, which also ends
the "log.SetLogger(...) was never called" warning. Docs gained a Logging
section and the test env var; the KVM provider execution log records run
4 (guest hang at GRUB) that prompted this.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
The first live run showed the trace working but noisy: testr printed
ts/level/msg and the per-run constants on every line, the error text
appeared twice, host appeared twice on image-cache lines, and the Go
method name was less useful than the libvirt function it maps to.

The tracer now logs rpc=virDomainLookupByName (go-libvirt's names are the
public API names without the vir prefix), error plus libvirtError (code
name) and libvirtCode, and image.go stops re-adding host. The integration
test replaces testr with a compact logr sink: time, logger name, the rpc
as headline, then fields, with provider/host/name omitted since the first
line of the run states them. Docs and execution log updated.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Run 5 on the real host bisected the guest hang: the Debian 13 image
hangs after GRUB under SeaBIOS with or without our seed and with either
CPU model, and boots under OVMF. The image's legacy boot chain is the
problem, not the provider.

images.<key>.firmware is "uefi" (default) or "bios". The domain XML
emits <os firmware="efi"> with secure boot off, so libvirt selects the
OVMF binary and manages the NVRAM file, which the existing nvram undefine
flag removes. Direct-URL images default to UEFI too. OVMF joins the
hypervisor prerequisites; sample, config table, known gaps, decision log
and the execution log record the finding.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
The known-gaps entry, decision log, sample comment and builder comment
blamed the host; the cause is trixie's GRUB config ("terminal_output
gfxterm serial" with a serial console and no video device), reported
and reproduced upstream and still open. UEFI remains the default for the
reason recorded; bookworm images are noted as unaffected.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
docs/kvm-provider.md walks through key generation, ssh-copy-id,
ssh-keyscan under the address the operator dials, and the Secret from
the private key plus ~/.ssh/kvm_known_hosts. make kvm-ssh-secret runs
the same as an apply with KVM_SSH_KEY / KVM_KNOWN_HOSTS overrides and
refuses a .pub, the classic mistake. README mirrors the short form.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
The manager runs with a read-only root filesystem and the seed ISO
writer stages files in a temp directory, so the first in-cluster Create
failed with "creating iso writer: read-only file system". Mount a 64 MiB
emptyDir on /tmp.

That error is classified ErrPermanent by writeSeed, yet hostPool.call
treated every non-libvirt error as a transport failure and dropped the
cached SSH connection, redialling on each retry. Errors that already
carry a provider sentinel are local verdicts, not evidence about the
link; leave the connection alone for those.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
In the kind cluster two KVM Proxies with real cloud-configs booted fine
but never left Provisioning: the guest agent was not installed, so the
provider could not learn the IP. cloud-init merges vendor-data under
user-data with its default mergers, which keep the user-data's value
for any key both define and never append lists, so a cloud-config with
its own `packages:` silently dropped the vendor-data's packages and
runcmd. The integration test passed only because its user-data was
empty.

withGuestAgent now appends qemu-guest-agent to `packages` and the
enable command to `runcmd` of the Proxy's own cloud-config (skipping
entries already present) and re-renders it. Vendor-data is no longer
defaulted; `vendorData` is plain extra data. User-data that is not a
cloud-config document (script, #include, MIME) still gets the bootstrap
as vendor-data. A cloud-config that is not a YAML mapping, or whose
packages/runcmd is not a list, fails the Proxy as ErrPermanent.

Validated in-cluster: both Proxies Ready and healthy in two minutes, 204
through squid from the LAN. Docs, sample comment, CHANGELOG and the
plan execution log (Run 7) updated.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
kacerr added 1 commit 2026-09-10 23:42:29 +02:00
kacerr added 6 commits 2026-09-11 00:59:54 +02:00
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
reconcileDelete asked Get first and dropped the finalizer only on
not-found, so a permanent Get retried forever: a KVM host removed from
the config, or a providerID the provider cannot resolve, left the Proxy
in Terminating with no way out. It now tries Delete anyway, which is
idempotent and can still finish where Get cannot converge, and releases
the object when that succeeds.

crawl.example.com/skip-cleanup abandons the instance for the cases that
stay stuck, such as revoked credentials. It is checked before the
provider lookup, so it also frees a Proxy whose provider is gone from
the config.

In the KVM provider, Delete over an unconfigured host is now a no-op
success, mirroring removeVolumes over a missing pool. Get keeps failing
permanently there on purpose: the live path reads not-found as "rebuild
it", so a typo in hosts must not look like a missing VM.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
A host name is pasted into the providerID hosts/<name>/domains/<vm>, which
parseProviderID splits on "/", so a name containing a slash produced an ID
that never parsed again: Get, Delete and GC all failed permanently and the
VM leaked with the Proxy's finalizer stuck.

The image map key has the same defect and lands in a file name rather than
an ID: base-<key>.<format> in the host's storage pool. Both now have to
match a plain identifier pattern. Machine-type keys are left alone; they
are only ever compared, never embedded.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
The kvm-ssh Secret is mounted optional, but kvm.New read the key and
known_hosts eagerly and registry.Build aborts the whole provider set on a
constructor error, so a missing or misnamed Secret exited the manager
before any controller started and took the kubernetes and gcp providers
down with it.

lazyAuth loads the material on the first connection and caches it once it
works, so a Secret created after the manager starts heals the affected
proxies on the next reconcile with no restart. A missing file classifies
transient for that reason; a key that does not parse is permanent.

New still checks both files and logs a WARNING: line when they are
unreadable, keeping the startup diagnostic the eager load was there for.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Merging the bootstrap into each Proxy's cloud-config was the wrong
mechanism twice over. Detection only matched a literal #cloud-config
first line, so a jinja template or a MIME archive still fell back to
vendor-data, where cloud-init's default mergers drop it — the exact
failure the merge existed to prevent. And the YAML round-trip re-typed
unquoted scalars: version: 1.10 reached the guest as 1.1, comments were
dropped and keys reordered.

Neither is worth patching, because vendor-data delivered as a shell
script bypasses the merger entirely: cloud-init hands vendor-data to its
own handler chain, writes scripts to a separate directory and runs them
from cc_scripts_vendor, after the user's packages and before the user's
runcmd. The merge could not have been rescued anyway — merge_how in
user-data governs only the first source, and merge_how in vendor-data is
discarded before the document is stored.

The Proxy's cloud-init now reaches the seed byte for byte in any format.
installGuestAgent (default true) turns the script off; a configured
vendorData travels beside it as a MIME multipart, declared text/plain so
cloud-init re-sniffs it and this code never classifies user content.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
kacerr added 1 commit 2026-09-11 08:25:41 +02:00
Collapse duplicated logic the review found in PR #5 without changing
behaviour: one releaseFinalizer helper for the four finalizer exits in
reconcileDelete, classify reusing isClassified and provider.Class, the
image URL check and format/firmware values shared from the provider
package, imageSource and the metadata parser embedding their config
structs instead of copying fields, and the SSH loader as a small struct
that keeps only the SSH fields and is seeded by New instead of loading
the key twice. Tracing builds its V(2)-only lists only at V(2).

Tests: drop a duplicate New test, fold near-identical tests into tables
(connection drops, metadata parsing, cached images), add mustSSHAuth,
and use wantClass where classes were checked by hand.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
kacerr added 1 commit 2026-09-11 08:30:40 +02:00
The default manager config gains a kvm-home provider reaching beelink
over Tailscale, the provider sample names the same host, and the
manager kustomization uses the locally built kvm-dev image.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
kacerr merged commit eb8f075f7a into main 2026-09-11 17:02:33 +02:00
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Reference: kacerr/egress-proxies-operator#5