Grafana Cloud PDC agent and Istio

#istio #pdc #kubernetes #grafanacloud

When you need to setup Grafana Private Data source Connect in Kubernetes you need to apply some tricks in order to make it work.

Here I will describe what I did in order to use it.

Used links:

Official guide

I created my custom helm chart that contains next deployment.yaml:

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: {{ .Release.Name }}
    name: {{ .Release.Name }}
  name: {{ .Release.Name }}
spec:
  replicas: {{ .Values.minReplicas }}
  selector:
    matchLabels:
      name: {{ .Release.Name }}
  strategy:
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 0
    type: RollingUpdate
  template:
    metadata:
      labels:
        name: {{ .Release.Name }}
      annotations:
        proxy.istio.io/config: |
          holdApplicationUntilProxyStarts: true
    spec:
      containers:
        - name: {{ .Release.Name }}
          env:
            - name: CLUSTER
              valueFrom:
                secretKeyRef:
                  key: cluster
                  name: {{ .Release.Name }}
            - name: HOSTED_GRAFANA_ID
              valueFrom:
                secretKeyRef:
                  key: hostedGrafanaId
                  name: {{ .Release.Name }}
            - name: TOKEN
              valueFrom:
                secretKeyRef:
                  key: token
                  name: {{ .Release.Name }}
          args:
            - -cluster
            - "$(CLUSTER)"
            - -gcloud-hosted-grafana-id
            - "$(HOSTED_GRAFANA_ID)"
            - -token
            - "$(TOKEN)"
            - -ssh-key-file
            - "/home/pdc/.ssh/grafana_pdc_v3"
          image: grafana/pdc-agent:{{ .Values.version }}
          imagePullPolicy: Always
          resources:
            limits:
              cpu: 1024m
              memory: 1Gi
            requests:
              cpu: 1024m
              memory: 1Gi
          securityContext:
            allowPrivilegeEscalation: false
            privileged: false
            runAsNonRoot: true
            capabilities:
              drop:
                - all
      securityContext:
        runAsUser: 30000
        runAsGroup: 30000
        fsGroup: 30000
      topologySpreadConstraints:
        - labelSelector:
            matchLabels:
              app: {{ .Release.Name }}
          maxSkew: 1
          minDomains: {{ .Values.minReplicas }}
          topologyKey: "kubernetes.io/hostname"
          whenUnsatisfiable: DoNotSchedule
          matchLabelKeys:
            - pod-template-hash
          nodeAffinityPolicy: Honor
          nodeTaintsPolicy: Honor
        - labelSelector:
            matchLabels:
              app: {{ .Release.Name }}
          maxSkew: 1
          minDomains: {{ .Values.minReplicas }}
          topologyKey: "topology.kubernetes.io/zone"
          whenUnsatisfiable: DoNotSchedule
          matchLabelKeys:
            - pod-template-hash
          nodeAffinityPolicy: Honor
          nodeTaintsPolicy: Honor

Nuances

Istio

Sidecar

Set holdApplicationUntilProxyStarts: true for the pods, so they will not start until istio sidecar not starts.

Access (optional)

If you not allow outbound traffic - set ServiceEntry that will allow several urls.
What I have for API access:

apiVersion: networking.istio.io/v1alpha3
kind: ServiceEntry
metadata:
  name: {{ .Values.name }}-api
spec:
  hosts:
    - private-datasource-connect-api-<cluster>.grafana.net
  location: MESH_EXTERNAL
  ports:
    - name: https
      number: 443
      protocol: HTTPS
  resolution: DNS

What I have for ssh access:

apiVersion: networking.istio.io/v1alpha3
kind: ServiceEntry
metadata:
  name: {{ .Values.name }}-ssh
spec:
  hosts:
    - private-datasource-connect-<cluster>.grafana.net
  location: MESH_EXTERNAL
  ports:
    - name: tcp
      number: 22
      protocol: TCP
  resolution: DNS

Grafana PDC config

Key Pair force regeneration

I set -ssh-key-file to /home/pdc/.ssh/grafana_pdc_v3 because if there already host in allowed list(for ssh access) - then it not starts and fail in constant restarts.
This should be addressed in GitHub issue

Log level

Currently, in PDC agent log level set to debug level.
Unfortunately, as of today, when you use -ssh-key-file parameter you cannot change it.
This should be addressed in GitHub issue

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