Problem
The Feature Flags UI (aka Flagd UI) is not accessible via the frontend-proxy at http://localhost:8080/feature as stated in the documentation.
Chart version: opentelemetry-demo-0.38.1
Steps to reproduce
- Install the chart as described in the documentation.
- Either port-forward the frontend-proxy or expose it via Ingress or Gateway
- Navigate to the
/feature path to access the Feature Flags UI
- You will get a 503, since no backend is available
Cause
As you can see in the following snippet, the flagd-ui container is deployed as a Sidecar container in the flagd pod.
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flagd: |
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enabled: true |
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imageOverride: |
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repository: "ghcr.io/open-feature/flagd" |
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tag: "v0.12.8" |
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useDefault: |
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env: true |
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replicas: 1 |
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ports: |
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- name: rpc |
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value: 8013 |
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- name: ofrep |
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value: 8016 |
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env: |
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- name: FLAGD_METRICS_EXPORTER |
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value: otel |
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- name: FLAGD_OTEL_COLLECTOR_URI |
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value: $(OTEL_COLLECTOR_NAME):4317 |
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- name: GOMEMLIMIT |
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value: 60MiB |
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resources: |
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limits: |
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memory: 75Mi |
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command: |
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- "/flagd-build" |
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- "start" |
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- "--port" |
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- "8013" |
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- "--ofrep-port" |
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- "8016" |
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- "--uri" |
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- "file:./etc/flagd/demo.flagd.json" |
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mountedEmptyDirs: |
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- name: config-rw |
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mountPath: /etc/flagd |
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# flagd-ui as a sidecar container in the same pod so the flag json file can be shared |
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sidecarContainers: |
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- name: flagd-ui |
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useDefault: |
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env: true |
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service: |
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port: 4000 |
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env: |
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- name: FLAGD_METRICS_EXPORTER |
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value: otel |
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- name: OTEL_EXPORTER_OTLP_ENDPOINT |
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value: http://$(OTEL_COLLECTOR_NAME):4318 |
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- name: FLAGD_UI_PORT |
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value: "4000" |
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- name: SECRET_KEY_BASE |
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value: yYrECL4qbNwleYInGJYvVnSkwJuSQJ4ijPTx5tirGUXrbznFIBFVJdPl5t6O9ASw |
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- name: PHX_HOST |
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value: localhost |
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resources: |
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limits: |
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memory: 250Mi |
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volumeMounts: |
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- name: config-rw |
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mountPath: /app/data |
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initContainers: |
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- name: init-config |
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image: busybox |
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command: ["sh", "-c", "cp /config-ro/demo.flagd.json /config-rw/demo.flagd.json && cat /config-rw/demo.flagd.json"] |
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volumeMounts: |
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- mountPath: /config-ro |
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name: config-ro |
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- mountPath: /config-rw |
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name: config-rw |
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additionalVolumes: |
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- name: config-ro |
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configMap: |
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name: flagd-config |
Therefore it is exposed by the flagd service at port 4000, as you can see in the generated manifest:
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# Source: opentelemetry-demo/templates/component.yaml |
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apiVersion: v1 |
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kind: Service |
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metadata: |
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name: flagd |
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labels: |
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helm.sh/chart: opentelemetry-demo-0.38.1 |
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opentelemetry.io/name: flagd |
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app.kubernetes.io/component: flagd |
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app.kubernetes.io/name: flagd |
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app.kubernetes.io/version: "2.1.3" |
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app.kubernetes.io/part-of: opentelemetry-demo |
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app.kubernetes.io/managed-by: Helm |
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spec: |
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type: ClusterIP |
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ports: |
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- port: 8013 |
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name: rpc |
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targetPort: 8013 |
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- port: 8016 |
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name: ofrep |
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targetPort: 8016 |
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- port: 4000 |
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name: tcp-service-0 |
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targetPort: 4000 |
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selector: |
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opentelemetry.io/name: flagd |
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--- |
However, in values.yml, the frontend-proxy component points to the flagd-ui service, which does not exist.
We shall set FLAGD_UI_HOST=flagd.
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- name: FLAGD_HOST |
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value: flagd |
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- name: FLAGD_PORT |
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value: "8013" |
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- name: FLAGD_UI_HOST |
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value: flagd-ui |
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- name: FLAGD_UI_PORT |
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value: "4000" |
This error probably originates from the fact that in the .env file in https://github.com/open-telemetry/opentelemetry-demo/ they set FLAGD_UI_HOST=flagd-ui.
But that .env file is used for their docker-compose deployment, where there is indeed a dedicated service for flagd-ui.
