Deploy OneAgent on Kubernetes for application-only monitoring

Dynatrace also offers the option to inject OneAgent into Kubernetes pods. OneAgent Operator runs an admission controller that can modify pods to inject OneAgent by adding an init container. This init container will download the OneAgent package and configure the other containers to be monitored.

1. Create a Dynatrace namespace.

$ kubectl create namespace dynatrace

2. Install OneAgent Operator.
   OneAgent Operator acts on its dynatrace namespace. You can also observe the logs of OneAgent Operator.

$ kubectl apply -f https://github.com/Dynatrace/dynatrace-oneagent-operator/releases/latest/download/kubernetes.yaml
$ kubectl -n dynatrace logs -f deployment/dynatrace-oneagent-operator

3. Create the secret holding the PaaS token for authentication to the Dynatrace cluster.

$ kubectl -n dynatrace create secret generic oneagent --from-literal="paasToken=PAAS_TOKEN"

4. Save the OneAgent custom resource definition. The rollout of Dynatrace OneAgent for application-only installations is governed by the custom resource type OneAgentAPM. Retrieve the cr-apm.yaml file from the GitHub repository.

https://github.com/Dynatrace/dynatrace-oneagent-operator/blob/master/deploy/cr-apm.yaml 

5. Adapt the values of the custom resource as follows:

• Required Specify the spec.apiUrl parameter, which is the URL of your Dynatrace environment, for your SaaS, Managed, or ActiveGate instance.

• Optional Configure network zones by setting the spec.networkZone parameter to your network zone.

spec:
  networkZone: <your_network_zone>

See network zones for more information.

6. Label your namespaces.
   OneAgent Operator injects into all pods that belong to namespaces labeled oneagent.dynatrace.com/instance. The value for this label must be the name of the OneAgentAPM instance that you want to use to configure the corresponding namespaces. You must label all namespaces you want to monitor. Note that the namespaces can point to different OneAgentAPM instances.

$ kubectl label namespace default oneagent.dynatrace.com/instance=oneagentapm

7. Configure the injection.
   You can configure the injection through Kubernetes annotations.

Note: These settings apply to all containers running on the corresponding pods.

$ kubectl annotate namespace default oneagent.dynatrace.com/inject=false
namespace/default annotated

apiVersion: apps/v1
kind: Deployment
metadata:
  name: sample-app
spec:
  selector:
    matchLabels:
      app: sample-app
  strategy:
    type: Recreate
  template:
    metadata:
      annotations:
        # The configuration for app-only injection should be set here.
        oneagent.dynatrace.com/technologies: "java,nginx"
        oneagent.dynatrace.com/flavor: "musl"
        oneagent.dynatrace.com/inject: "true"
        oneagent.dynatrace.com/install-path: "/dynatrace"
        oneagent.dynatrace.com/installer-url: "https://my-custom-url/route/file.zip"
      labels:
        app: sample-app
    spec:
      containers:
      - command: [ "java", "-jar", "/app/app.jar" ]
        image: "my-image"
        # ...

8. Create the custom resource

kubectl apply -f cr-apm.yaml

9. Deploy your applications.
   All deployed pods will then be monitored.

Follow the steps below to integrate OneAgent into the application image.

1. Sign in to Docker with your Dynatrace environment ID as username and PaaS token as password.

   docker login -u <environmentID> <ACTIVEGATE-ADDRESS>
   

2. Add the following lines of code to the application image, after the last FROM command:

   COPY --from=<ADDRESS>/linux/oneagent-codemodules:<TECHNOLOGY> / /
   ENV LD_PRELOAD /opt/dynatrace/oneagent/agent/lib64/liboneagentproc.so
   

   where:

• <ADDRESS> is:
  • EnvironmentActiveGate: <ActiveGateaddress:9999>
  • SAAS: {yourenvid}.live.dynatrace.com
  • Managed: {ManagedAddress}
• <TECHNOLOGY> is: The OneAgent code module required for your application. Valid options are all, java, apache, nginx, nodejs, dotnet, php, go, and sdk. You can specify several code modules, separated by hyphen (-), for example java-go. Including specific technology-support options, rather than support for all technology options, results in a smaller OneAgent package.

COPY --from=<ACTIVEGATE-ADDRESS>/linux/oneagent-codemodules-musl:<TECHNOLOGY> / /
ENV LD_PRELOAD /opt/dynatrace/oneagent/agent/lib64/liboneagentproc.so

3. Build your application image.
   Build the Docker image from your Dockerfile to use it in your Kubernetes environment.

$ docker build -t yourapp .

You can monitor your application containers with a different Dynatrace environment.

For OneAgent version 1.139 or higher, if you have an existing application image where you have already added the OneAgent code modules for a specific Dynatrace environment, you can have the OneAgent report to another Dynatrace environment without rebuilding your application image.
For this, you need to make a call to the REST endpoint of your second Dynatrace environment. Don't forget to adapt the respective placeholders <environmentID> and <token>.

$ curl "https://<environmentID>.live.dynatrace.com/api/v1/deployment/installer/agent/connectioninfo?Api-Token=<token>"

In return, you get a JSON object that covers the required information that needs to be passed as an environment variable to the application container.
Make sure you set the environment variables of the application container as described below:

• DT_TENANT: equals tenantUUID
• DT_TENANTTOKEN: equals tenantToken
• DT_CONNECTION_POINT: semi-colon separated list of communicationEndpoints

4. Optional Configure network zones

   You can configure network zones as an environment variable:

   • DT_NETWORK_ZONE: equals your.network.zone

   See network zones for more information.

5. Optional Configure a proxy address
   

   In case you run an environment with proxy, you need to set the DT_PROXY environment variable in the application container to pass the proxy credentials to OneAgent.

   Note: For Alpine Linux-based containers, you might need to update the wget shipped with the Alpine image to allow for proxy authentication for the download of OneAgent.

With the container runtime integration, OneAgent is made available to the application container via an initContainer—your application image remains unaffected.

To integrate OneAgent into your application at runtime, extend your deployment template as follows.

# your application containers
      containers:
      - name: customer-app
        image: tomcat
        env:
        - name: LD_PRELOAD
          value: /opt/dynatrace/oneagent/agent/lib64/liboneagentproc.so
        - name: DT_NETWORK_ZONE
          value: <your_network_zone>
        volumeMounts:
        - mountPath: /opt/dynatrace/oneagent
          name: oneagent

# initcontainer to download OneAgent
      initContainers:
      - name: install-oneagent
        image: alpine:3.8
        command:
        - /bin/sh
        args:
        - -c
        - ARCHIVE=$(mktemp) && wget -O $ARCHIVE "$DT_API_URL/v1/deployment/installer/agent/unix/paas/latest?Api-Token=$DT_PAAS_TOKEN&$DT_ONEAGENT_OPTIONS" && unzip -o -d /opt/dynatrace/oneagent $ARCHIVE && rm -f $ARCHIVE
        env:
        - name: DT_API_URL
          value: https://<Your-environment-ID>.live.dynatrace.com/api
        - name: DT_PAAS_TOKEN
          value: <paastoken>
        - name: DT_ONEAGENT_OPTIONS
          value: flavor=<FLAVOR>&include=<TECHNOLOGY>
        volumeMounts:
        - mountPath: /opt/dynatrace/oneagent
          name: oneagent

# Make OneAgent available as a volume
      volumes:
      - name: oneagent
        emptyDir: {}

• In the # initContainer to download OneAgent and # Make OneAgent available as a volume sections, add the initContainer, which will download OneAgent and make it available as a volume.

• In the DT_ONEAGENT_OPTIONS section, set the OneAgent code module required for your compiler flavor (FLAVOR) and application (TECHNOLOGY).

  • Valid options for flavor are default, musl.
  • Valid options for technology are all, java, apache, nginx, nodejs, dotnet, php, go, and sdk.

If you want to specify several code modules, use the following syntax: &include=technology1&include=technology2.

Note: If you include specific technology-support options rather than 'support for all technologies' options, you'll get a smaller OneAgent package.

• In the # your application containers section, add the newly created volume to the container of your application. Also add the LD_PRELOAD environment variable.

• Optional In the # your application containers section, configure network zones:

containers:
  env:
  - name: DT_NETWORK_ZONE
    value: <your_network_zone>

See network zones for more information.

• Optional Configure a proxy address.
  

  In case you run an environment with proxy, you need to set the DT_PROXY environment variable in the application container to pass the proxy credentials to OneAgent.

  Note: For Alpine Linux-based containers, you might need to update the wget shipped with the Alpine image to allow for proxy authentication for the download of OneAgent.