Setup Scraping for sending to Polar Signals Cloud

While the primary way to write data to Polar Signals Cloud is to use the agent, there may be reasons to want to write additional data that cannot be obtained via the agent.

Languages

Here is a table of Languages/runtimes and libraries that can be used to gather additional types of profiling data.

Language/runtime	Heap	Allocations	Blocking	Mutex Contention	Extra
Go	Yes	Yes	Yes	Yes	Goroutine, fgprof
Python	Yes	No	No	No
NodeJS	Yes	No	No	No

Setup

The below manifests deploy the Polar Signals scraper, which discovers containers in a Kubernetes cluster and starts scraping them.

info

The configuration is identical to the Prometheus scrape config, Kubernetes is just used as an example here.

kubectl apply -f polarsignals-scraper.yaml

---
apiVersion: v1
kind: Namespace
metadata:
  name: polarsignals
  labels:
    pod-security.kubernetes.io/audit: privileged
    pod-security.kubernetes.io/enforce: privileged
    pod-security.kubernetes.io/warn: privileged
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  labels:
    app.kubernetes.io/component: profile-scraper
    app.kubernetes.io/instance: polarsignals-scraper
    app.kubernetes.io/name: polarsignals-scraper
  name: polarsignals-scraper
  namespace: polarsignals
rules:
- apiGroups:
  - ""
  resources:
  - pods
  verbs:
  - list
  - watch
- apiGroups:
  - ""
  resources:
  - nodes
  verbs:
  - get
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  labels:
    app.kubernetes.io/component: profile-scraper
    app.kubernetes.io/instance: polarsignals-scraper
    app.kubernetes.io/name: polarsignals-scraper
  name: polarsignals-scraper
  namespace: polarsignals
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: polarsignals-scraper
subjects:
- kind: ServiceAccount
  name: polarsignals-scraper
  namespace: polarsignals
---
kind: ConfigMap
metadata:
  name: polarsignals-scraper-config
  namespace: polarsignals
apiVersion: v1
data:
  polarsignals-scraper.yaml: |-
    object_storage:
      bucket:
        type: "FILESYSTEM"
        config:
          directory: "./data"
    # MODIFY THIS TO YOUR NEEDS
    scrape_configs:
    - job_name: 'kubernetes-pods'
      kubernetes_sd_configs:
      - role: pod
      relabel_configs:
      - action: labelmap
        regex: __meta_kubernetes_pod_label_app_kubernetes_io_(.+)
        replacement: "app_kubernetes_io_$1"
      - source_labels: [__meta_kubernetes_namespace]
        action: replace
        target_label: namespace
      - source_labels: [__meta_kubernetes_pod_name]
        action: replace
        target_label: pod
      - source_labels: [__meta_kubernetes_pod_container_name]
        action: replace
        target_label: container
---
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app.kubernetes.io/component: profile-scraper
    app.kubernetes.io/instance: polarsignals-scraper
    app.kubernetes.io/name: polarsignals-scraper
  name: polarsignals-scraper
  namespace: polarsignals
spec:
  replicas: 1
  selector:
    matchLabels:
      app.kubernetes.io/component: profile-scraper
      app.kubernetes.io/instance: polarsignals-scraper
      app.kubernetes.io/name: polarsignals-scraper
  template:
    metadata:
      labels:
        app.kubernetes.io/component: profile-scraper
        app.kubernetes.io/instance: polarsignals-scraper
        app.kubernetes.io/name: polarsignals-scraper
        app.kubernetes.io/version: v0.20.0
    spec:
      securityContext:
        fsGroup: 65534
        runAsUser: 65534
      containers:
      - args:
        - /parca
        - --config-path=/var/polarsignals-scraper/polarsignals-scraper.yaml
        - --store-address=grpc.polarsignals.com:443
        - --bearer-token-file=/var/polarsignals-secret/token
        - --mode=scraper-only
        image: ghcr.io/parca-dev/parca:v0.20.0
        livenessProbe:
          exec:
            command:
            - /grpc_health_probe
            - -v
            - -addr=:7070
          initialDelaySeconds: 5
        name: polarsignals-scraper
        ports:
        - containerPort: 7070
          name: http
        readinessProbe:
          exec:
            command:
            - /grpc_health_probe
            - -v
            - -addr=:7070
          initialDelaySeconds: 10
        terminationMessagePolicy: FallbackToLogsOnError
        resources: {}
        volumeMounts:
        - mountPath: /tmp
          name: tmp
        - mountPath: /var/polarsignals-scraper
          name: polarsignals-scraper-config
        - mountPath: /var/polarsignals-secret
          name: token
      nodeSelector:
        kubernetes.io/os: linux
      serviceAccountName: polarsignals-scraper
      tolerations:
      - effect: NoSchedule
        operator: Exists
      - effect: NoExecute
        operator: Exists
      volumes:
      - emptyDir: {}
        name: tmp
      - configMap:
          name: polarsignals-scraper-config
        name: polarsignals-scraper-config
      - secret:
          secretName: polarsignals-agent
        name: token
---
apiVersion: v1
kind: ServiceAccount
metadata:
  labels:
    app.kubernetes.io/component: profile-scraper
    app.kubernetes.io/instance: polarsignals-scraper
    app.kubernetes.io/name: polarsignals-scraper
  name: polarsignals-scraper
  namespace: polarsignals

Configuration

The configuration is identical to the Prometheus scrape config. Anything described in the Prometheus documentation can be used to configure the Polar Signals Scraper too.

A common thing to do is not scrape all containers in a Kubernetes cluster, but only a specific container name for example. That can be done by adding the following snippet:

      - source_labels: [__meta_kubernetes_pod_container_name]
        action: keep
        regex: my-container

If you ever need help with specific changes to your configuration feel free to join our Discord server and ask!