Install New Relic Java agent for Docker

This document explains a basic installation of the APM agent for Java applications in a Docker container. We discuss required configurations and also explore some optional configurations, including:

• How to use identical New Relic configuration files for each container, regardless of the environment where the containers are used
• How to use the Docker layer when every agent in every environment needs slightly different configuration data
• How to disable the New Relic agent in some environments and enable it in others

Although we don't discuss advanced options here, you can install the Java agent in Docker volumes and use your Docker container image in other software such as Swarm, ECS, AKS, EKS, OpenShift, and Kubernetes. Our Docker examples refer to Tomcat, so if you are using another application server, refer to your vendor’s documentation.

Get the Java agent

Download newrelic-java.zip using curl, Invoke-WebRequest (PowerShell), or the New Relic UI:

Set up the installation directory

You can unzip the newrelic-java.zip file wherever it is convenient for you. In the subsequent sections we assume you extracted it in the current working directory, which puts the files we need in ./newrelic.

Modify startup scripts

The startup script that contains the command to start your application server must include Java’s built-in argument -javaagent. We recommend that you set this argument with the JAVA_OPTS environment variable. The value of that argument must contain the location where you ADD the Java APM agent’s jar file to the image.

For example, with Tomcat, use commands like these in the Dockerfile:

RUN mkdir -p /usr/local/tomcat/newrelic
ADD ./newrelic/newrelic.jar /usr/local/tomcat/newrelic/newrelic.jar
ENV JAVA_OPTS="$JAVA_OPTS -javaagent:/usr/local/tomcat/newrelic/newrelic.jar"

Set agent configurations

By default, agent behavior is controlled by configuration entries in newrelic.yml, which is typically located in the same directory as the agent. This section explains how to override these newrelic.yml configurations by using environment variables or Java system properties in the Dockerfile.

Before we look at some specific configurations, here’s how to load newrelic.yml using the Dockerfile:

ADD ./newrelic/newrelic.yml /usr/local/tomcat/newrelic/newrelic.yml

For a basic Docker installation, complete these configurations:

• Application name
• License key
• Logs
• Environment (optional)
• Agent enabled (optional)

Application name

The application name is a configuration you set to identify your application in New Relic.

Replace MY_APP_NAME with your application name in one of these Dockerfile commands:

ENV NEW_RELIC_APP_NAME="MY_APP_NAME"

ENV JAVA_OPTS="$JAVA_OPTS -Dnewrelic.config.app_name='MY_APP_NAME'"

After you boot the container, your application name appears in New Relic.

License key

This configuration is required for you to report data to your New Relic account.

To copy your license key:

1. Go to the API keys UI and get a license key.

2. In one of these Dockerfile commands, replace MY_LICENSE_KEY with your license key:

   Option	Command
   Environment variable	ENV NEW_RELIC_LICENSE_KEY="MY_LICENSE_KEY" Copy
   Java system property	ENV JAVA_OPTS="$JAVA_OPTS -Dnewrelic.config.license_key='MY_LICENSE_KEY'" Copy

Logs

By default, logs are written into the logs directory relative to the location of newrelic.jar. Make sure that the user account that starts your application server also has the right to perform tasks such as:

• Creating the logs directory.
• Creating and appending to the log files in that directory.

Here’s a Dockerfile example where tomcat is the user who starts Tomcat:

RUN mkdir -p /usr/local/tomcat/newrelic/logs
RUN chown -R tomcat:tomcat /usr/local/tomcat/newrelic/logs

You can also send the logs to STDOUT by adding one of the following to the Dockerfile:

ENV NEW_RELIC_LOG_FILE_NAME=STDOUT

ENV JAVA_OPTS=-Dnewrelic.config.log_file_name=STDOUT

Environment (optional)

You can pass either a Java property or an environment variable to determine which of the environment-specific sections the agent uses in newrelic.yml. Use this approach if you prefer to have the newrelic.yml file control environment-specific configurations instead of passing all the configurations via Docker.

Here’s a Dockerfile example of passing the newrelic.environment Java system property via Docker to use the custom value dev in the environment section of newrelic.yml:

1. Using the shell form of the CMD instruction, include a reference to a new environment variable you choose (for example, ENV):

   CMD java -Dnewrelic.environment=$ENV -jar myjar.jar

   Copy

2. In your docker run command line, include an argument to set the environment variable in the container:

   bash

   Copy

   $
   docker run -it -e "ENV=dev" myDockerImage

Agent enabled (optional)

This configuration controls whether the agent is enabled. Let’s say you want the same Docker image for every installation. However, you don’t want to run the New Relic agent every time an engineer spins up a test app because you don’t want to run up your instance count.

This problem can be solved using the newrelic.environment Java system property.

1. In the main body of newrelic.yml, disable the Java agent by setting agent_enabled: false.
2. In specific environment sections of newrelic.yml, set agent_enabled: true.

Then, you can run specific agents by specifying the environment at runtime.

Additional Tomcat Dockerfile examples

FROM tomcat:9
# Add the newrelic.jar and -javaagent parameters
RUN mkdir -p /usr/local/tomcat/newrelic
ADD ./newrelic/newrelic.jar /usr/local/tomcat/newrelic/
ENV JAVA_OPTS="$JAVA_OPTS -javaagent:/usr/local/tomcat/newrelic/newrelic.jar"
# Add the configuration file
ADD ./newrelic/newrelic.yml /usr/local/tomcat/newrelic/
# An example of setting a system property config
ENV JAVA_OPTS="$JAVA_OPTS -Dnewrelic.config.app_name='My Application'"
# An example of setting an Environment variable config
ENV NEW_RELIC_LICENSE_KEY="license_key"
# Config to include the agent logs in Docker's stdout logging
ENV JAVA_OPTS="$JAVA_OPTS -Dnewrelic.config.log_file_name=STDOUT"
EXPOSE 8080
CMD ["catalina.sh", "run"]

FROM openjdk:8
ADD my-application.jar /app
ADD newrelic.jar  /app
ADD newrelic.yml  /app 
ENV NEW_RELIC_APP_NAME="My Application"
ENV NEW_RELIC_LICENSE_KEY="license_key"
ENV NEW_RELIC_LOG_FILE_NAME="STDOUT"
ENTRYPOINT ["java","-javaagent:/app/newrelic.jar","-jar","/app/my-application.jar"]

Next steps

Now that you have a basic agent installation in Docker, here are some additional steps to consider:

• Review other configurations for the agent.
• Read a detailed Support Forum post about Docker and New Relic.