fix: harden registry availability and add publish phase timings (#1211)

## Summary

Daily ~17:00 UTC `Publish Endpoint Latency` and `Availability < 95%`
alerts are caused by both registry pods exit-0'ing within seconds of
each other and racing with the still-recovering `registry-pg-rw`
endpoint on restart. Separately, the default compute SA had no project
IAM roles, so `fluentbit-gke` and the GMP collector were silently
dropping every log line and time series — which is why none of this was
visible in Cloud Logging.

All Kubernetes/IAM changes apply uniformly to staging and prod.

## Changes

- **GCP IAM** (`deploy/pkg/providers/gcp/provider.go`) — grant the
default compute SA `logging.logWriter`, `monitoring.metricWriter`,
`monitoring.viewer`, and `stackdriver.resourceMetadata.writer`. Already
applied live; this just encodes it in Pulumi.
- **Pod resilience** (`deploy/pkg/k8s/registry.go`) —
- `PodDisruptionBudget` (`minAvailable: 1`) prevents a synchronized
voluntary disruption.
- `TopologySpreadConstraints` (`ScheduleAnyway`, hostname) keeps the PDB
from deadlocking node drains when both pods co-locate.
- `StartupProbe` (30 × 5s = 150s) protects the DB-retry budget from the
liveness probe.
  - Memory bump 128→256Mi request, 256→512Mi limit.
- **Startup retry** (`cmd/registry/main.go`) — replace silent `return`
on initial DB-ping failure with bounded retry-with-backoff (8 attempts,
1→8s capped, 10s per-attempt). A brief endpoint flap no longer cascades
into a restart loop.
- **Diagnostic log** (`internal/service/registry_service.go`) — emit
`validate_ms` on each publish (success and failure). Validate fans out
to npm/PyPI/OCI with 10s per-host timeouts and is the most likely
contributor to publish latency. Total request duration is already
covered by the existing `http.request.duration` histogram.

## Calibration

The IAM, PDB, topology-spread, startup-probe, and DB-retry pieces are
mitigations — they reduce blast radius regardless of root cause. The
`validate_ms` log is the diagnostic for identifying the trigger when the
alert fires next. Single-PG SPOF (`deploy/pkg/k8s/postgres.go:57`)
remains a follow-up; today's evidence shows PG was a victim, not the
cause.

## Test plan

- [x] `go build ./...` and `go vet ./...` clean for both modules
- [x] `make lint` clean (12 pre-existing issues under `deploy/` are not
in `make lint`)
- [x] `go test -race -count=1 ./internal/... ./cmd/...` green
- [x] IAM applied live; `fluentbit-gke` and GMP no longer hitting
`IAM_PERMISSION_DENIED`
- [ ] After deploy, verify the next 17:00 UTC firing surfaces
`validate_ms` in Cloud Logging

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This commit is contained in:
Radoslav Dimitrov 2026-04-27 09:09:50 -04:00 • committed by GitHub
commit b24d6c7657
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
4 changed files with 165 additions and 17 deletions

View file

@ -57,16 +57,32 @@ func main() {
// Initialize configuration
cfg := config.NewConfig()
// Create a context with timeout for PostgreSQL connection
ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
defer cancel()
// Connect to PostgreSQL
db, err = database.NewPostgreSQL(ctx, cfg.DatabaseURL)
if err != nil {
log.Printf("Failed to connect to PostgreSQL: %v", err)
// Connect to PostgreSQL with bounded retry. The DB endpoint can flap briefly
// during voluntary disruptions (node drains, rollouts) and without retry the
// pod exits cleanly, restarts, then races with the still-recovering service
// — turning a transient blip into a multi-minute outage.
const (
maxStartupAttempts = 8
perAttemptTimeout = 10 * time.Second
initialBackoff = 1 * time.Second
maxBackoff = 8 * time.Second
)
backoff := initialBackoff
for attempt := 1; ; attempt++ {
attemptCtx, attemptCancel := context.WithTimeout(context.Background(), perAttemptTimeout)
db, err = database.NewPostgreSQL(attemptCtx, cfg.DatabaseURL)
attemptCancel()
if err == nil {
break
}
if attempt >= maxStartupAttempts {
log.Printf("Failed to connect to PostgreSQL after %d attempts: %v", attempt, err)
return
}
log.Printf("PostgreSQL not reachable (attempt %d/%d): %v, retrying in %s", attempt, maxStartupAttempts, err, backoff)
time.Sleep(backoff)
backoff = min(backoff*2, maxBackoff)
}
// Store the PostgreSQL instance for later cleanup
defer func() {

View file

@ -10,6 +10,7 @@ import (
"github.com/pulumi/pulumi-kubernetes/sdk/v4/go/kubernetes/helm/v3"
metav1 "github.com/pulumi/pulumi-kubernetes/sdk/v4/go/kubernetes/meta/v1"
networkingv1 "github.com/pulumi/pulumi-kubernetes/sdk/v4/go/kubernetes/networking/v1"
policyv1 "github.com/pulumi/pulumi-kubernetes/sdk/v4/go/kubernetes/policy/v1"
"github.com/pulumi/pulumi/sdk/v3/go/pulumi"
"github.com/pulumi/pulumi/sdk/v3/go/pulumi/config"
@ -95,6 +96,22 @@ func DeployMCPRegistry(ctx *pulumi.Context, cluster *providers.ProviderInfo, env
},
},
Spec: &corev1.PodSpecArgs{
// Soft-spread pods across nodes so the PodDisruptionBudget below can't
// deadlock a node drain when both pods happen to co-locate.
// `ScheduleAnyway` keeps single-node clusters (e.g. constrained dev
// envs) schedulable while still preferring spread under normal load.
TopologySpreadConstraints: corev1.TopologySpreadConstraintArray{
&corev1.TopologySpreadConstraintArgs{
MaxSkew: pulumi.Int(1),
TopologyKey: pulumi.String("kubernetes.io/hostname"),
WhenUnsatisfiable: pulumi.String("ScheduleAnyway"),
LabelSelector: &metav1.LabelSelectorArgs{
MatchLabels: pulumi.StringMap{
"app": pulumi.String("mcp-registry"),
},
},
},
},
Containers: corev1.ContainerArray{
&corev1.ContainerArgs{
Name: pulumi.String("mcp-registry"),
@ -169,6 +186,18 @@ func DeployMCPRegistry(ctx *pulumi.Context, cluster *providers.ProviderInfo, env
Value: pulumi.String("*"),
},
},
// StartupProbe protects the DB-retry budget in cmd/registry/main.go:
// 30 × 5s = 150s allowed before liveness/readiness take over, which
// covers the worst-case retry budget (8 attempts × 10s + ~40s sleep).
StartupProbe: &corev1.ProbeArgs{
HttpGet: &corev1.HTTPGetActionArgs{
Path: pulumi.String("/v0/health"),
Port: pulumi.Int(8080),
},
PeriodSeconds: pulumi.Int(5),
FailureThreshold: pulumi.Int(30),
TimeoutSeconds: pulumi.Int(3),
},
LivenessProbe: &corev1.ProbeArgs{
HttpGet: &corev1.HTTPGetActionArgs{
Path: pulumi.String("/v0/health"),
@ -187,11 +216,11 @@ func DeployMCPRegistry(ctx *pulumi.Context, cluster *providers.ProviderInfo, env
},
Resources: &corev1.ResourceRequirementsArgs{
Requests: pulumi.StringMap{
"memory": pulumi.String("128Mi"),
"memory": pulumi.String("256Mi"),
"cpu": pulumi.String("100m"),
},
Limits: pulumi.StringMap{
"memory": pulumi.String("256Mi"),
"memory": pulumi.String("512Mi"),
},
},
},
@ -204,6 +233,31 @@ func DeployMCPRegistry(ctx *pulumi.Context, cluster *providers.ProviderInfo, env
return nil, err
}
// Keep at least one registry pod available during voluntary disruptions
// (node drains, evictions, etc.) so a synchronized eviction can't take both
// pods down at once.
_, err = policyv1.NewPodDisruptionBudget(ctx, "mcp-registry", &policyv1.PodDisruptionBudgetArgs{
Metadata: &metav1.ObjectMetaArgs{
Name: pulumi.String("mcp-registry"),
Namespace: pulumi.String("default"),
Labels: pulumi.StringMap{
"app": pulumi.String("mcp-registry"),
"environment": pulumi.String(environment),
},
},
Spec: &policyv1.PodDisruptionBudgetSpecArgs{
MinAvailable: pulumi.Int(1),
Selector: &metav1.LabelSelectorArgs{
MatchLabels: pulumi.StringMap{
"app": pulumi.String("mcp-registry"),
},
},
},
}, pulumi.Provider(cluster.Provider))
if err != nil {
return nil, err
}
// Create Service
service, err := corev1.NewService(ctx, "mcp-registry", &corev1.ServiceArgs{
Metadata: &metav1.ObjectMetaArgs{

View file

@ -3,9 +3,12 @@ package gcp
import (
"encoding/base64"
"fmt"
"strings"
"github.com/pulumi/pulumi-gcp/sdk/v8/go/gcp"
"github.com/pulumi/pulumi-gcp/sdk/v8/go/gcp/container"
"github.com/pulumi/pulumi-gcp/sdk/v8/go/gcp/organizations"
"github.com/pulumi/pulumi-gcp/sdk/v8/go/gcp/projects"
"github.com/pulumi/pulumi-gcp/sdk/v8/go/gcp/storage"
"github.com/pulumi/pulumi-kubernetes/sdk/v4/go/kubernetes"
corev1 "github.com/pulumi/pulumi-kubernetes/sdk/v4/go/kubernetes/core/v1"
@ -58,6 +61,49 @@ func createGCPProvider(ctx *pulumi.Context, name string) (*gcp.Provider, error)
return nil, nil
}
// grantNodeServiceAccountRoles grants the default compute service account the standard
// GKE node roles required for log shipping (fluentbit-gke) and metrics scraping
// (managed Prometheus). New GCP projects no longer auto-grant Editor to the default
// compute SA, so these have to be set explicitly or every pod log/metric is dropped.
func grantNodeServiceAccountRoles(ctx *pulumi.Context, projectID string, gcpProvider *gcp.Provider) error {
invokeOpts := []pulumi.InvokeOption{}
resourceOpts := []pulumi.ResourceOption{}
if gcpProvider != nil {
invokeOpts = append(invokeOpts, pulumi.Provider(gcpProvider))
resourceOpts = append(resourceOpts, pulumi.Provider(gcpProvider))
}
project, err := organizations.LookupProject(ctx, &organizations.LookupProjectArgs{
ProjectId: pulumi.StringRef(projectID),
}, invokeOpts...)
if err != nil {
return fmt.Errorf("failed to look up project number for node SA bindings: %w", err)
}
nodeSA := fmt.Sprintf("serviceAccount:%s-compute@developer.gserviceaccount.com", project.Number)
roles := []string{
"roles/logging.logWriter",
"roles/monitoring.metricWriter",
"roles/monitoring.viewer",
"roles/stackdriver.resourceMetadata.writer",
}
for _, role := range roles {
name := fmt.Sprintf("node-sa-%s", strings.ReplaceAll(strings.TrimPrefix(role, "roles/"), ".", "-"))
_, err := projects.NewIAMMember(ctx, name, &projects.IAMMemberArgs{
Project: pulumi.String(projectID),
Role: pulumi.String(role),
Member: pulumi.String(nodeSA),
}, resourceOpts...)
if err != nil {
return fmt.Errorf("failed to grant %s to node SA: %w", role, err)
}
}
return nil
}
// CreateCluster creates a Google Kubernetes Engine cluster
func (p *Provider) CreateCluster(ctx *pulumi.Context, environment string) (*providers.ProviderInfo, error) {
// Get configuration
@ -152,6 +198,13 @@ func (p *Provider) CreateCluster(ctx *pulumi.Context, environment string) (*prov
return nil, fmt.Errorf("failed to create node pool: %w", err)
}
// Grant the default compute service account the standard GKE node roles so the
// fluentbit-gke and managed Prometheus collectors can ship logs and metrics.
// Without these, every pod log line and time series fails with IAM_PERMISSION_DENIED.
if err := grantNodeServiceAccountRoles(ctx, projectID, gcpProvider); err != nil {
return nil, err
}
// Create Kubernetes provider using the cluster directly
k8sProvider, err := kubernetes.NewProvider(ctx, "k8s-provider", &kubernetes.ProviderArgs{
Kubeconfig: pulumi.All(cluster.Endpoint, cluster.MasterAuth).ApplyT(func(args []any) (string, error) {

View file

@ -4,6 +4,7 @@ import (
"context"
"errors"
"fmt"
"log/slog"
"time"
"github.com/jackc/pgx/v5"
@ -85,15 +86,29 @@ func (s *registryServiceImpl) CreateServer(ctx context.Context, req *apiv0.Serve
})
}
// createServerInTransaction contains the actual CreateServer logic within a transaction
// createServerInTransaction contains the actual CreateServer logic within a transaction.
func (s *registryServiceImpl) createServerInTransaction(ctx context.Context, tx pgx.Tx, req *apiv0.ServerJSON) (*apiv0.ServerResponse, error) {
// Validate the request
if err := validators.ValidatePublishRequest(ctx, *req, s.cfg); err != nil {
return nil, err
serverJSON := *req
// Validate the request. ValidatePublishRequest fans out to npm/PyPI/OCI for
// registry-ownership checks with 10s per-host timeouts, so it's the most likely
// contributor to publish latency. Log validate_ms on both success and failure
// so the next /v0/publish latency alert is diagnostic — a slow upstream that
// times out into a validation error is exactly the case we need to see.
validateStart := time.Now()
validateErr := validators.ValidatePublishRequest(ctx, serverJSON, s.cfg)
validateMs := time.Since(validateStart).Milliseconds()
if validateErr != nil {
slog.WarnContext(ctx, "publish validate failed",
"server_name", serverJSON.Name,
"version", serverJSON.Version,
"validate_ms", validateMs,
"error", validateErr.Error(),
)
return nil, validateErr
}
publishTime := time.Now()
serverJSON := *req
// Acquire advisory lock to prevent concurrent publishes of the same server
if err := s.db.AcquirePublishLock(ctx, tx, serverJSON.Name); err != nil {
@ -161,7 +176,17 @@ func (s *registryServiceImpl) createServerInTransaction(ctx context.Context, tx
}
// Insert new server version
return s.db.CreateServer(ctx, tx, &serverJSON, officialMeta)
resp, err := s.db.CreateServer(ctx, tx, &serverJSON, officialMeta)
if err != nil {
return nil, err
}
slog.InfoContext(ctx, "publish complete",
"server_name", serverJSON.Name,
"version", serverJSON.Version,
"validate_ms", validateMs,
)
return resp, nil
}
// recalculateLatest picks the highest non-deleted version of the given server and flags it