8. Write startup.sh script

Create scripts/startup.sh file.

The filename and directory can be what you want.

#!/bin/bash

# Run jar
DEPLOY_PATH="/home/ec2-user"
DEPLOY_LOG_PATH="/home/ec2-user/deploy.log"
DEPLOY_ERROR_LOG_PATH="/home/ec2-user/deploy_err.log"
APPLICATION_LOG_PATH="/home/ec2-user/application.log"

ALL_JAR="/home/ec2-user/build/*.jar" # Expects one jar file exists.
JAR_PATH=$(ls $ALL_JAR)
JAR_NAME=$(basename $JAR_PATH)

echo "> Build filename: $JAR_NAME" >> $DEPLOY_LOG_PATH

echo "> Build file copy" >> $DEPLOY_LOG_PATH
cp $JAR_PATH $DEPLOY_PATH

echo "> Get application PID if there is one running" >> $DEPLOY_LOG_PATH
CURRENT_PID=$(pgrep -f $JAR_NAME)

if [ -z "$CURRENT_PID" ]; then
    echo "> No application running" >> $DEPLOY_LOG_PATH
else
    echo "> kill -9 $CURRENT_PID" >> $DEPLOY_LOG_PATH
    kill -9 $CURRENT_PID
    sleep 5
fi

JAVA_OPTS="-Dspring.jpa.hibernate.ddl-auto=update"

JAR_PATH=$DEPLOY_PATH/$JAR_NAME
echo "> JAR_PATH $JAR_PATH" >> $DEPLOY_LOG_PATH
echo "> JAVA_OPTS $JAVA_OPTS" >> $DEPLOY_LOG_PATH
nohup java $JAVA_OPTS -jar $JAR_PATH >> $APPLICATION_LOG_PATH 2>> $DEPLOY_ERROR_LOG_PATH &

This script will be executed after CodeDeploy delivering an artifact to the EC2.

nohup is "no hang up", which will keep the process even if the parent process is terminated. The parent process here is CodeDeploy AfterInstall hooks.

Check this filename at AfterInstall in appspec.yml

hooks:
  AfterInstall:
    - location: scripts/startup.sh
      timeout: 60
      runas: ec2-user