Dynatrace | Pod Runtime Injection for Application Only Monitoring on Kubernetes

We use this approach when we wish to monitor a specific pod deployed on kubernetes without making any changes in our image.

Here, Dynatrace OneAgent operator is made available to the application container via an initContainer—your application image remains unaffected.

Pre-requisites

Generate a PaaS token.

Steps to get these tokens:

1. Go to your Dynatrace UI, on the left side you have menu bar, Manage →Access tokens
2. Click on Generate new token
3. Give meaningful token name and choose the scope — PaaS integration — Installer download, PaaS integration — Support alert, then, generate the PaaS token.

generate PaaS token for runtime pod injection application-only monitoring

Pod Runtime Injection

Now you will need to modify your application yaml file to add init container for Dynatrace OneAgent

create a volume named oneagent before modifying your application deployment yaml file.

# your application containers
      containers:
      - name: customer-app
        image: tomcat
        env:
        - name: LD_PRELOAD
          value: /opt/dynatrace/oneagent/agent/lib64/liboneagentproc.so
        volumeMounts:
        - mountPath: /opt/dynatrace/oneagent
          name: oneagent
   volumes:
      - name: oneagent
        emptyDir: {}
  
  
# initcontainer to download OneAgent
      initContainers:
      - name: install-oneagent
        image: alpine:latest
        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

Now, we have to make a few changes in the application yaml, please follow along

For your application container part of your application deployment yaml file

  #here in your environment variables add these lines.
        env:
        - name: LD_PRELOAD
          value: /opt/dynatrace/oneagent/agent/lib64/liboneagentproc.so
# in volumeMounts add these lines below
        volumeMounts:
        - mountPath: /opt/dynatrace/oneagent
          name: oneagent
# in volumes add the below lines, remember we already created oneagent volume
   volumes:
      - name: oneagent
        emptyDir: {}

Now, we have to create an init container, start from the end of your application deployment file

#here in the image alpine:latest is being pulled from docker.io, if you are using private repo then follow the below steps
# docker pull alpine:latest
# docker tag alpine:latest your-repo/alpine:latest
# doker push your-repo/alpine:latest
# Now, replace the value in image key below with your image-> your-repo/alpine:latest
initContainers:
      - name: install-oneagent
        image: alpine:latest
        command:
        - /bin/sh
# if your dynatrace url certificate is expired or not supported the use --no-check-certificate in wget command below
        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
# here, below give the correct url of your dyntrace portal- DT_API_URL
# give the passtoken you generated in pre-requisite step - DT_PAAS_TOKEN
# for DT_ONEAGENT_OPTIONS, you have to pick correct value depending upon your application
# valid values for flavor -> default, musl, multidistro 
# default if for glibc, musl is for musl binaries, multidistro is for both, if you don't know what to use go with multidistro, but mostly in corporate environment default option will work.
# valid values for technology -> all, java, apache, nginx, nodejs, dotnet, php, go, and sdk
# if you don't know what to use then go ahead with all. The size of the file will be larger though
#If you want to specify several code modules, use the following syntax: &include=technology1&include=technology2
        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

Now, save the modified deployment yaml file and apply.

You will be able to see the pod now in Dynatrace portal under Infrastructure → hosts.

Click here to see the dynatrace URL for implementing the same.

Thank You for checking this out, appreciate your time 😄

You may also checkout automatic injection approach here.

SETTING UP DYNATRACE MANUALLY FOR APPLICATION ONLY MONITORING ON KUBERNETES