0049c2ae730ce4388da369e906710055bdf26e09
4 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Pim van Pelt
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0049c2ae73 |
VPP reconciler: event-driven sync, pool failover, bug fixes
This commit wires the checker's state machine through to the VPP dataplane:
every backend state transition flows through a single code path that
recomputes the effective per-backend weight (with pool failover) and pushes
the result to VPP. Along the way several latent bugs in the state machine
and the sync path were fixed.
internal/vpp/reconciler.go (new)
- New Reconciler type subscribes to checker.Checker events and, on every
transition, calls Client.SyncLBStateVIP for the affected frontend. This
is the ONLY place in the codebase where backend state changes cause VPP
calls — the "single path" discipline requested during design.
- Defines an EventSource interface (checker.Checker satisfies it) so the
dependency direction stays vpp → checker; the checker never imports vpp.
internal/vpp/client.go
- Renamed ConfigSource → StateSource. The interface now has two methods:
Config() and BackendState(name) — the reconciler and the desired-state
builder both need live health state to compute effective weights.
- SetConfigSource → SetStateSource; internal cfgSrc field → stateSrc.
- New getStateSource() helper for internal locked access.
- lbSyncLoop still uses the state source for its periodic drift
reconciliation; it's fully idempotent and runs the same code path as
event-driven syncs.
internal/vpp/lbsync.go
- desiredAS grows a Flush bool so the mapping function can signal "on
transition to weight 0, flush existing flow-table entries".
- asFromBackend is now the single source of truth for the state →
(weight, flush) rule. Documented with a full truth table. Takes an
activePool parameter so it can distinguish "up in active pool" from
"up but standby".
- activePoolIndex(fe, states) implements priority failover: returns the
index of the first pool containing any StateUp backend. pool[0] wins
when at least one member is up; pool[1] takes over when pool[0] is
empty; and so on. Defaults to 0 (unobservable, since all backends map
to weight 0 when nothing is up).
- desiredFromFrontend snapshots backend states once, computes activePool,
then walks every backend through asFromBackend. No more filtering on
b.Enabled — disabled backends stay in the desired set so they keep
their AS entry in VPP with weight=0. The previous filter caused delAS
on disable, which destroyed the entry and broke enable afterwards.
- EffectiveWeights(fe, src) exported helper that returns the per-pool
per-backend weight map for one frontend. Used by the gRPC GetFrontend
handler and robot tests to observe failover without touching VPP.
- reconcileVIP computes flush at the weight-change call site:
flush = desired.Flush && cur.Weight > 0 && desired.Weight == 0
This ensures only the *transition* to disabled flushes sessions —
steady-state syncs with already-zero weight skip the call entirely.
- setASWeight now plumbs IsFlush into lb_as_set_weight.
internal/vpp/lbsync_test.go (new)
- TestAsFromBackend: 15 cases locking down the truth table, including
failover scenarios (up in standby pool, up promoted in pool[1]).
- TestActivePoolIndex: 8 cases covering pool[0]-has-up, pool[0]-all-down,
all-disabled, all-paused, all-unknown, nothing-up-anywhere, and
three-tier failover.
- TestDesiredFromFrontendFailover: 5 end-to-end scenarios wiring a fake
StateSource through desiredFromFrontend and asserting the final
per-IP weight map. Exercises the complete pipeline without VPP.
internal/checker/checker.go
- Added BackendState(name) (health.State, bool) — one-line method that
satisfies vpp.StateSource. The checker is otherwise unchanged.
- EnableBackend rewritten to reuse the existing worker (parallel to
ResumeBackend). The old code called startWorker which constructed a
brand-new Backend via health.New, throwing away the transition
history; the resulting 'backend-transition' log showed the bogus
from=unknown,to=unknown. Now uses w.backend.Enable() to record a
proper disabled→unknown transition and launches a fresh goroutine.
- Static (no-healthcheck) backends now fire their synthetic 'always up'
pass on the first iteration of runProbe instead of sleeping 30s
first. Previously static backends sat in StateUnknown for 30s after
startup — useless for deterministic testing and surprising for
operators. The fix is a simple first-iteration flag.
internal/health/state.go
- New Enable(maxHistory) method parallel to Disable. Transitions the
backend from whatever state it's in (typically StateDisabled) to
StateUnknown, resets the health counter to rise-1 so the expedited
resolution kicks in on the first probe result, and emits a transition
with code 'enabled'.
proto/maglev.proto
- PoolBackendInfo gains effective_weight: the state-aware weight that
would be programmed into VPP (distinct from the configured weight in
the YAML). Exposed via GetFrontend.
internal/grpcapi/server.go
- frontendToProto takes a vpp.StateSource, computes effective weights
via vpp.EffectiveWeights, and populates PoolBackendInfo.EffectiveWeight.
- GetFrontend and SetFrontendPoolBackendWeight updated to pass the
checker in.
cmd/maglevc/commands.go
- 'show frontends <name>' now renders every pool backend row as
<name> weight <cfg> effective <eff> [disabled]?
so both values are always visible. The VPP-style key/value format
avoids the ANSI-alignment pitfall we hit earlier and makes the output
regex-parseable for robot tests.
cmd/maglevd/main.go
- Construct and start the Reconciler alongside the VPP client. Two
extra lines, no other changes to startup.
tests/01-maglevd/maglevd-lab/maglev.yaml
- Two new static backends (static-primary, static-fallback) and a new
failover-vip frontend with one backend per pool. No healthcheck, so
the state machine resolves them to 'up' immediately via the synthetic
pass. Used by the failover robot tests.
tests/01-maglevd/01-healthcheck.robot
- Three new test cases exercising pool failover end-to-end:
1. primary up, secondary standby (initial state)
2. disable primary → fallback takes over (effective weight flips)
3. enable primary → fallback steps back
All run without VPP: they scrape 'maglevc show frontends <name>' and
regex-match the effective weight in the output. Deterministic and
fast (~2s total) because the static backends don't probe.
- Two helper keywords: Static Backend Should Be Up and
Effective Weight Should Be.
Net result: 16/16 robot tests pass. Backend state transitions now
flow through a single documented path (checker event → reconciler →
SyncLBStateVIP → desiredFromFrontend → asFromBackend → reconcileVIP →
setASWeight), and the pool failover / enable-after-disable / static-
backend-startup bugs are all fixed.
|
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Pim van Pelt
|
1815675fb6 |
Distinguish disabled from removed backend state; add make fixstyle
Add StateDisabled for operator-initiated disable, keeping StateRemoved for backends that disappear during a config reload. Previously both used StateRemoved, which was confusing: "removed" implies the backend no longer exists in config, but a disabled backend is still present and can be re-enabled on the fly. - health: add StateDisabled with String() "disabled", Disable() method with probe code "disabled". Record() rejects probes in all three inactive states (paused, disabled, removed). - checker: DisableBackend calls backend.Disable() instead of Remove(). - docs: healthchecks.md rewritten for pause (goroutine cancelled, not just results discarded), and separate disabled/removed state rows. user-guide.md updated to match. - Makefile: add fixstyle target (gofmt -w .). |
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Pim van Pelt
|
4ab3096c8b |
Add Prometheus metrics endpoint; containerize integration tests
Prometheus metrics (internal/metrics/, cmd/maglevd/) - New --metrics-addr flag (default :9091, env MAGLEV_METRICS_ADDR) serving /metrics via promhttp. - Gauge metrics scraped on demand via a custom prometheus.Collector: maglev_backend_state, maglev_backend_health, maglev_backend_enabled, maglev_frontend_pool_backend_weight. - Inline counter/histogram metrics updated per probe: maglev_probe_total (by backend, type, result, code), maglev_probe_duration_seconds (by backend, type), maglev_backend_transitions_total (by backend, from, to). - StateSource interface in metrics package breaks the import cycle with checker; checker.Checker satisfies it via GetBackendInfo. Integration tests - Run maglevd inside a containerlab node (debian:trixie-slim with build/ bind-mounted) instead of on the host. Eliminates port collisions with any host maglevd. - maglevc commands run via docker exec into the maglevd container. - Add 6 Prometheus test cases: endpoint reachable, all backends report state=up, probe counters non-zero, duration histogram populated, pool weights correct, transition counters present. |
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Pim van Pelt
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8bde00eb61 |
Fix pause to cancel probe goroutine; add Robot Framework integration tests
Pause semantics - PauseBackend now cancels the probe goroutine so no HTTP/TCP/ICMP traffic is sent while the backend is paused. Previously the goroutine kept running and results were silently discarded. - ResumeBackend launches a fresh probe goroutine on the existing worker, preserving transition history. The backend re-enters unknown state. Integration tests (tests/01-maglevd/) - Containerlab topology with 3 nginx:alpine backends on a dedicated management network (172.20.30.0/24) with static IPs. - maglevd config with 200ms HTTP health-check interval for fast test convergence (rise=2, fall=2). - 8 test cases: deploy lab, start maglevd, all backends reach up, nginx logs confirm probes arriving, pause stops probes (probe count stable), resume restarts probes, disable stops probes, enable restarts probes. VPP dataplane test (tests/02-vpp-lb/) - Rewrite 01-e2e-lab.robot to match the actual single-VPP topology: test client-to-server ping through VPP bridge domains and verify nginx is serving on all app servers. The previous version referenced a non-existent topology file and tested OSPF/BFD between two VPP nodes that don't exist in this lab. Build infrastructure - Add 'make robot-test' target with TEST= for suite selection. - Add tests/.venv target for Robot Framework virtualenv. - Make IMAGE optional in rf-run.sh. - Add .gitignore entries for test output, venv, logs, and clab state. |