YT04‐Configure database environment variable in Tomcat

Install psql

sudo apt update
sudo apt install postgresql-client-common

Where is Tomcat located?

ps aux | grep tomcat

Tomcat paths

-Dcatalina.base=/var/lib/tomcat10
-Dcatalina.home=/usr/share/tomcat10

Type	Path
CATALINA_BASE (runtime config)	/var/lib/tomcat10
CATALINA_HOME (installation)	/usr/share/tomcat10

Open config file

vim /etc/default/tomcat10

Add your variables

If you use System.getProperty(...)

JAVA_OPTS="$JAVA_OPTS -Djava.awt.headless=true -Djava.net.preferIPv4Stack=true -DAPP_DB_URL=jdbc:postgresql://aws-1-ap-southeast-1.pooler...

Choose Transaction Pooler host to ensure the server uses a reachable IPv4 endpoint. Otherwise, you will get "Network is unreachable"

Restart Tomcat

systemctl restart tomcat10

Check Tomcat status

systemctl status tomcat10