[amazon-cloudwatch-agent-operator] Route SM/PM by cloudwatch.aws/scraper annotation#399
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wenegiemepraise wants to merge 8 commits into
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[amazon-cloudwatch-agent-operator] Route SM/PM by cloudwatch.aws/scraper annotation#399wenegiemepraise wants to merge 8 commits into
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…er startup The target-allocator declared the enable-prometheus-cr-watcher flag name as a constant but never registered it on the flag set, while the operator passes --enable-prometheus-cr-watcher whenever PrometheusCR.enabled is true. Because args are parsed with pflag.ExitOnError, the unregistered flag caused the binary to print 'unknown flag' and exit(2), putting the target-allocator pod into CrashLoopBackOff. This change registers the flag and ORs it with the YAML prometheus_cr.enabled setting, then fixes three latent defects that were previously unreachable because the binary crashed first: - promOperator: set a non-empty Namespace on the synthetic Prometheus object so the prometheus-operator config generator no longer panics with 'namespace can't be empty' in store.ForNamespace. - promOperator: set EvaluationInterval so the generated config does not render an empty global.evaluation_interval, which the prometheus config parser rejects with 'empty duration string'. - main: create and register service-discovery metrics and pass them to discovery.NewManager; passing a nil sdMetrics map makes every SD provider fail to register, yielding zero discovered targets. RELEASE_NOTES updated.
Add a regression test asserting that loading a Target Allocator config whose static scrape job omits scrape_protocols still yields a non-empty ScrapeProtocols on every loaded scrape config. This is defaulted by the pinned Prometheus library during yaml.UnmarshalStrict into the prometheus Config type, so the distributed /scrape_configs payload is never empty and the agent's prometheus-receiver validation passes. The test fails fast if a future dependency or load-path change drops this defaulting.
The pod-template restart-trigger sha256 was computed from Spec.Config only, so a change to Spec.Prometheus (rendered into a separate ConfigMap) left the pod template byte-identical and the workload controller did not roll the pods. Fold the serialized Spec.Prometheus (PrometheusConfig.Yaml()) into the hash input when it is non-empty, so a Prometheus-only change bumps the pod-template annotation and triggers a rolling restart, matching agent-config behavior. When no Prometheus config is set the hash input is byte-identical to the agent config alone, leaving non-Prometheus agents unaffected.
Add a per-node allocation strategy so each CloudWatch agent (DaemonSet, one per node) scrapes only the ServiceMonitor/PodMonitor targets on its own node, eliminating cross-node/cross-AZ scrape traffic. Targets that cannot be matched to a node-local agent (node-less endpoints, nodes without a Ready agent) fall back to consistent-hashing so they are never silently dropped. - allocation/per_node.go: perNodeAllocator (node index, consistent-hashing fallback ring, unassigned tracking, descriptive logging) + registration. - allocation/strategy.go: Collector.NodeName, NewCollector(name, node), WithFallbackStrategy option, targets_unassigned gauge. - collector/collector.go: capture pod.Spec.NodeName, skip empty-NodeName pods, handle watch.Modified so a collector's node is picked up once scheduled (fixes targets being stuck on the fallback after a DaemonSet rollout). - target/target.go: GetNodeName() from __meta_kubernetes_*_node_name labels. - config + main: FallbackAllocationStrategy wiring. - apis/v1alpha1 + CRD: allocationStrategy enum gains "per-node". - internal/manifests/targetallocator/configmap.go: emit per-node strategy and the consistent-hashing fallback from the CR.
# Conflicts: # cmd/amazon-cloudwatch-agent-target-allocator/main.go
Route ServiceMonitor/PodMonitor discovery across CloudWatch agents by the cloudwatch.aws/scraper annotation on the monitor CR. A monitor annotated cloudwatch.aws/scraper: cluster-scraper is scraped only by the cluster-scraper agent's Target Allocator; all others only by the per-node agent's. Add a scraperRole field to the Target Allocator prometheusCR config (spec.targetAllocator.prometheusCR.scraperRole) and a client-side annotation filter in the TA watcher (annotationRoleMatches) applied during monitor discovery. The cluster-scraper role keeps only annotated monitors; the default (empty) role keeps only unannotated ones, so the two roles partition monitors with no overlap and no gap.
Add a LoadConfig-level test proving the scraper annotation filter is applied during monitor discovery (cluster-scraper and default roles keep/skip the right monitors), and a ConfigMap test asserting scraper_role is emitted when set on the prometheusCR.
Refactor the annotation filter into PrometheusCRWatcher.selectsMonitor and log each ServiceMonitor/PodMonitor the cluster-scraper agent claims via the cloudwatch.aws/scraper annotation (the override event). Add unit tests bringing the routing logic to 100% statement coverage: annotationRoleMatches and selectsMonitor (incl. asserting the override log fires only for the cluster-scraper role), a LoadConfig-level routing test, and a configmap scraper_role assertion.
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Summary
Route ServiceMonitor/PodMonitor discovery across CloudWatch agents by the
cloudwatch.aws/scraperannotation on the monitor CR. A monitor annotatedcloudwatch.aws/scraper: cluster-scraperis scraped only by the cluster-scraper agent's TargetAllocator; all others only by the per-node agent's.
What
spec.targetAllocator.prometheusCR.scraperRolefield (Target Allocator configscraper_role).annotationRoleMatches) applied during monitordiscovery in
LoadConfig.cluster-scraperrole keeps only annotated monitors; the empty(default) role keeps only unannotated ones — complementary, so every monitor is owned by exactly
one agent (no double-scrape, no gap).
Why annotation (not label)
The routing key is behavioural config, not identity. Both agents' TAs already list all monitors
into their cache and filter client-side, and the two roles' selections union to the full set — so
server-side label filtering would gain nothing here. Filtering by annotation is a few lines in the
existing
ListAllcallback.Testing
go build ./...and unit tests pass, incl. newTestAnnotationRoleMatches(8 cases + partition invariant).cluster-scraper TA
/jobs; an unannotated one only in the per-node TA/jobs.GOPROXY=direct GOSUMDB=off(offline proxy); CI is the authoritative gate.Dependencies / stacking
Stacks on the per-node allocation operator work (#398,
ta-per-node-allocation). Companion helm PR:[amazon-cloudwatch-observability] Route SM/PM to cluster-scraper by annotation.