digma-helm-helper

This repo contains helpers to instrument an application running in a Helm file - without changing the original Helm file.

Prerequisite

Kustomize cli should be installed (https://kustomize.io/)

How to use:

For a full walkthrough see our documentation

What's in this repo

• example-app An example application to test the kustomize script on
• java-agent-initializer The source code of the init container used to provide the agent files
• kustomize scripts used to prepare the patch for you application Helm file

Troubleshooting

You got:

Error: error while running post render on files: error while running command /java-in-helm-instrumentation/kustomize/kustomize_build.sh. error output:
Error: add operation does not apply: doc is missing path: "/spec/template/spec/containers/0/volumeMounts/-": missing value
: exit status 1
helm.go:84: [debug] exit status 1
error while running command /java-in-helm-instrumentation/kustomize/kustomize_build.sh. error output:
Error: add operation does not apply: doc is missing path: "/spec/template/spec/containers/0/volumeMounts/-": missing value

The problem is that your volumeMounts for your container is empty and kustomize cannot add it.

How to fix: change line https://github.com/digma-ai/java-in-helm-instrumentation/blob/main/kustomize/kustomization.yaml#L32 from path: "/spec/template/spec/containers/0/volumeMounts/-" to path: "/spec/template/spec/containers/0/volumeMounts"

Kustomize updates only the first container of my deployment.

We assume you have only one container per deployment configuration, if it's not true for you, you need to duplicate patch https://github.com/digma-ai/java-in-helm-instrumentation/blob/main/kustomize/kustomization.yaml#L9 section and and change duplicated lines 11,27,32 with next number of your container (to 1, means second container).

Example:

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources:
  - generated-chart-output.yaml
patches:
  - path: patch.yaml
    target:
      labelSelector: <LABEL_TARGET_SELECTOR>
  - patch: |-
      - op: add
        path: "/spec/template/spec/containers/0/env/-"
        value:
          name: JAVA_TOOL_OPTIONS
          value: >-
            -javaagent:/shared-vol/otel-agent.jar 
            -Dotel.javaagent.extensions=/shared-vol/digma-ext.jar 
            -Dotel.exporter.otlp.traces.endpoint=<DIGMA_OTLP_ENDPOINT>
            -Dotel.traces.exporter=otlp 
            -Dotel.metrics.exporter=none 
            -Dotel.logs.exporter=none 
            -Dotel.exporter.otlp.protocol=grpc 
            -Dotel.instrumentation.common.experimental.controller.telemetry.enabled=true 
            -Dotel.instrumentation.common.experimental.view.telemetry.enabled=true 
            -Dotel.instrumentation.experimental.span-suppression-strategy=none 
            -Dotel.service.name=<SERVICE_NAME>
            -Dotel.instrumentation.digma-methods.enabled=false
      - op: add
        path: "/spec/template/spec/containers/0/env/-"
        value:
          name: OTEL_RESOURCE_ATTRIBUTES
          value: <SERVICE_OTEL_RESOURCE_ATTRIBUTES>
      - op: add
        path: "/spec/template/spec/containers/0/volumeMounts/-"
        value:
          name: shared
          mountPath: /shared-vol
      - op: add
        path: "/spec/template/spec/containers/1/env/-"
        value:
          name: JAVA_TOOL_OPTIONS
          value: >-
            -javaagent:/shared-vol/otel-agent.jar 
            -Dotel.javaagent.extensions=/shared-vol/digma-ext.jar 
            -Dotel.exporter.otlp.traces.endpoint=<DIGMA_OTLP_ENDPOINT>
            -Dotel.traces.exporter=otlp 
            -Dotel.metrics.exporter=none 
            -Dotel.logs.exporter=none 
            -Dotel.exporter.otlp.protocol=grpc 
            -Dotel.instrumentation.common.experimental.controller.telemetry.enabled=true 
            -Dotel.instrumentation.common.experimental.view.telemetry.enabled=true 
            -Dotel.instrumentation.experimental.span-suppression-strategy=none 
            -Dotel.service.name=<SERVICE_NAME>
      - op: add
        path: "/spec/template/spec/containers/1/env/-"
        value:
          name: OTEL_RESOURCE_ATTRIBUTES
          value: <SERVICE_OTEL_RESOURCE_ATTRIBUTES>
      - op: add
        path: "/spec/template/spec/containers/1/volumeMounts/-"
        value:
          name: shared
          mountPath: /shared-vol
    target:
      labelSelector: <LABEL_TARGET_SELECTOR>