Deploying the Pet Clinic Application

Prerequisites

For ease of deployment, we run the sample application in Docker containers. In order to deploy the application, you will need:

A host running MacOS or a Linux-based operating system with Docker installed. We use a t2.small EC2 instance running at AWS. (The application may run under Docker on Windows, but we have not tested it. The deployment process for Windows may differ somewhat from these instructions);
A New Relic Pro or Enterprise account.

Deployment Steps

Create mapped directories. Log into your host and create three directories: one for the New Relic agent and associated files, one for the Pet Clinic application itself, and the third for the application server’s log files. These directories will be mapped into the Docker container, allowing you to modify the application or New Relic configuration without rebuilding the container, and to easily view or clean up the logs.

In this example, the directories are named newrelic, webapps, and logs, and are created in the home directory of the logged-in user:
```
$ mkdir newrelic
$ mkdir webapps
$ mkdir logs
```
Download the New Relic Java agent. While still logged into your host, execute the following commands to download and extract the New Relic Java agent:
```
$ wget http://download.newrelic.com/newrelic/java-agent/newrelic-agent/current/newrelic-java.zip
$ unzip newrelic-java.zip
```
Replace the default newrelic.yml configuration file. Execute the following command to download a customized newrelic.yml file into the newrelic directory:
```
$ wget https://raw.githubusercontent.com/devopsschool-demo-labs-projects/newrelic-lab-setup/master/newrelic.yml -O newrelic/newrelic.yml
```
This file uses environment variables for the license key and app name, and disables the New Relic Java agent’s circuit breaker.

Download the Pet Clinic application. Execute the following command to download the petclinic.war file into the webapps directory:

$ wget https://github.com/devopsschool-demo-labs-projects/newrelic-generate-apm-data/raw/master/petclinic-1.0.war -O webapps/petclinic.war

Start the MySQL Docker container. Execute the following command to create a Docker container running MySQL:

$ docker run -d --name mysql \
    -e MYSQL_ROOT_PASSWORD="petclinic" \
    -e MYSQL_DATABASE="petclinic" \
    -e MYSQL_USER="petclinic" \
    -e MYSQL_PASSWORD="petclinic" \
    -p 3306:3306 mysql:5.5

Start the Apache Tomcat Docker container. Execute the following command to create a Docker container running Apache Tomcat. Replace the {your-license-key} placeholder with the license key of your New Relic account. If you wish, you may change the value of the NEW_RELIC_APP_NAME parameter:

$ docker run -it -d --tmpfs /run --tmpfs /tmp --name petclinic \
    -e NEW_RELIC_APP_NAME="New Relic Pet Clinic" \
    -e JAVA_OPTS="-Xms128m -Xmx320m -XX:MaxPermSize=128m -javaagent:/usr/local/tomcat/newrelic/newrelic.jar" \
    -e JDBC_CONNECTION_STRING="jdbc:mysql://mysql:3306/petclinic" \
    -e NEW_RELIC_LICENSE_KEY="{your-license-key}" \
    -v ~/newrelic:/usr/local/tomcat/newrelic \
    -v ~/webapps:/usr/local/tomcat/webapps \
    -v ~/logs:/usr/local/tomcat/logs \
    --link mysql:mysql -p 80:8080 tomcat:8.0

The above command maps the webapps folder on your host machine to Tomcat’s webapps folder inside the container; Tomcat should start the Pet Clinic application automatically.

Within a few minutes, you should be able to access the Pet Clinic application at http://{your-host-name}/petclinic.

Notes

As the Pet Clinic application runs, its application server creates log files that gradually consume disk space. If you find that disk space on your host is getting low, you may execute the following command to delete all but the last 7 days’ logs:

$ find ./logs \( -name '*.log' -o -name '*.txt' \) -type f -mtime +7 -exec rm -f {} \;

Some Linux distributions have a bug that causes Docker not to release disk space when containers and images are removed. If deleting log files does not free enough space, you may stop the Docker service, delete its files, and restart the service. This will delete all Docker containers on the host!

$ sudo service docker stop
$ sudo rm -rf /var/lib/docker
$ sudo service docker start

You may recreate the MySQL and Apache Tomcat containers by re-running the docker run commands (steps 5 and 6) above.