Companion code for "Deploying Spring Boot 4 on Kubernetes: Probes, Graceful Shutdown, Limits and JVM Ergonomics". A dependency outage under three probe-group setups, a rolling restart under load four ways (three runs each), the JVM's ergonomic choices for nine pod shapes, one GC-heavy load under five CPU limits with throttling counters, and an HPA driven by a Micrometer gauge through prometheus-adapter. Measured on k3s v1.36.4. Co-Authored-By: Claude Opus 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01C3TETMrqVUWeFkNtz3Jbo3
113 lines
4.2 KiB
YAML
113 lines
4.2 KiB
YAML
# prometheus-adapter v0.12.0 serving custom.metrics.k8s.io from one rule: the Micrometer gauge
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# app.inflight.requests, which Prometheus stores as app_inflight_requests.
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apiVersion: v1
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kind: ServiceAccount
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metadata: {name: prometheus-adapter, namespace: monitoring}
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---
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apiVersion: rbac.authorization.k8s.io/v1
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kind: ClusterRole
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metadata: {name: prometheus-adapter}
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rules:
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- apiGroups: [""]
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resources: [namespaces, pods, services, nodes]
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verbs: [get, list, watch]
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---
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apiVersion: rbac.authorization.k8s.io/v1
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kind: ClusterRoleBinding
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metadata: {name: prometheus-adapter}
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roleRef: {apiGroup: rbac.authorization.k8s.io, kind: ClusterRole, name: prometheus-adapter}
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subjects: [{kind: ServiceAccount, name: prometheus-adapter, namespace: monitoring}]
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---
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apiVersion: rbac.authorization.k8s.io/v1
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kind: ClusterRoleBinding
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metadata: {name: prometheus-adapter-auth-delegator}
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roleRef: {apiGroup: rbac.authorization.k8s.io, kind: ClusterRole, name: system:auth-delegator}
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subjects: [{kind: ServiceAccount, name: prometheus-adapter, namespace: monitoring}]
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---
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apiVersion: rbac.authorization.k8s.io/v1
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kind: RoleBinding
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metadata: {name: prometheus-adapter-auth-reader, namespace: kube-system}
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roleRef: {apiGroup: rbac.authorization.k8s.io, kind: Role, name: extension-apiserver-authentication-reader}
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subjects: [{kind: ServiceAccount, name: prometheus-adapter, namespace: monitoring}]
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---
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# The HPA controller reads custom metrics as this service account.
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apiVersion: rbac.authorization.k8s.io/v1
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kind: ClusterRole
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metadata: {name: custom-metrics-reader}
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rules:
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- apiGroups: [custom.metrics.k8s.io]
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resources: ["*"]
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verbs: [get, list]
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---
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apiVersion: rbac.authorization.k8s.io/v1
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kind: ClusterRoleBinding
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metadata: {name: hpa-custom-metrics-reader}
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roleRef: {apiGroup: rbac.authorization.k8s.io, kind: ClusterRole, name: custom-metrics-reader}
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subjects: [{kind: ServiceAccount, name: horizontal-pod-autoscaler, namespace: kube-system}]
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---
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apiVersion: v1
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kind: ConfigMap
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metadata: {name: prometheus-adapter, namespace: monitoring}
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data:
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config.yaml: |
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rules:
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# Micrometer "app.inflight.requests" -> Prometheus "app_inflight_requests" (dots become
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# underscores; a gauge gets no suffix). The series carries namespace/pod labels from the
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# scrape config, which is how the adapter attributes it to a pod.
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- seriesQuery: 'app_inflight_requests{namespace!="",pod!=""}'
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resources:
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overrides:
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namespace: {resource: namespace}
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pod: {resource: pod}
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name:
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matches: "^app_inflight_requests$"
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as: "app_inflight_requests"
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metricsQuery: 'avg_over_time(<<.Series>>{<<.LabelMatchers>>}[30s])'
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---
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apiVersion: apps/v1
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kind: Deployment
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metadata: {name: prometheus-adapter, namespace: monitoring}
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spec:
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replicas: 1
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selector: {matchLabels: {app: prometheus-adapter}}
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template:
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metadata: {labels: {app: prometheus-adapter}}
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spec:
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serviceAccountName: prometheus-adapter
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containers:
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- name: adapter
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image: registry.k8s.io/prometheus-adapter/prometheus-adapter:v0.12.0
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imagePullPolicy: Never
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args:
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- --prometheus-url=http://prometheus.monitoring.svc:9090/
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- --metrics-relist-interval=15s
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- --config=/etc/adapter/config.yaml
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- --secure-port=6443
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- --cert-dir=/tmp/cert
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ports: [{containerPort: 6443}]
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resources: {requests: {cpu: 50m, memory: 64Mi}, limits: {memory: 256Mi}}
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volumeMounts:
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- {name: config, mountPath: /etc/adapter}
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- {name: tmp, mountPath: /tmp}
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volumes:
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- {name: config, configMap: {name: prometheus-adapter}}
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- {name: tmp, emptyDir: {}}
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---
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apiVersion: v1
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kind: Service
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metadata: {name: prometheus-adapter, namespace: monitoring}
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spec:
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selector: {app: prometheus-adapter}
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ports: [{port: 443, targetPort: 6443}]
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---
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apiVersion: apiregistration.k8s.io/v1
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kind: APIService
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metadata: {name: v1beta1.custom.metrics.k8s.io}
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spec:
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service: {name: prometheus-adapter, namespace: monitoring}
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group: custom.metrics.k8s.io
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version: v1beta1
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insecureSkipTLSVerify: true # the adapter generated a self-signed cert; use cert-manager in real clusters
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groupPriorityMinimum: 100
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versionPriority: 100
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