deploying war files on wildfly

There seem to be multiple ways to deploy WAR files in Wildfly. 
https://www.baeldung.com/jboss-war-deploy

Just copying the WAR file to the wildfly/standalone/deployments directory seems the most easy for us to do. And if the WAR file is already exploded, we also need to create a appname.war.dodeploy marker file as mentioned in RedHat's documentation.

Change configuration files only after stopping wildfly -
/opt/bitnami/ctlscript.sh stop wildfly
on Bitnami Wildfly VM.

Takes ~15 sec to stop Wildfly

Takes ~5 minutes to start Wildfly and deploy wars if there are errors, but only a few seconds (less than a minute) if there are no errors.
Monitoring the log is a good way to judge if Wildfly is running or stopped - 
sudo tail -f /opt/bitnami/wildfly/standalone/log/server.log

Examples of configuration files which might need to be set up - 
wildfly/standalone/deployments/CAS.war/WEB-INF/deployerConfigContext.xml
wildfly/standalone/deployments/CAS.war/WEB-INF/cas.properties

wildfly/standalone/configuration/standalone.xml
wildfly/modules/org/CustomAppName/properties/configuration/main/Environment.properties

If a WAR file deployment fails with Null Pointer Exception (seen in the server.log file mentioned above), there is a good chance that this is due to some non-existent file or path mentioned in one of the properties files above. The usual culprit would be Windows-style paths for log or conf files. 

If a large number of WAR files are to be deployed, deployment may fail with Out of Memory errors. We can increase heap size and MetaSpace size by editing /opt/bitnami/wildfly/bin/standalone.conf line for JAVA_OPTS like

JAVA_OPTS="-Xms2G -Xmx10G -XX:MetaspaceSize=2G -XX:MaxMetaspaceSize=6G -Djava.net.preferIPv4Stack=true"

Edit - Adding data-sources - if needed, we can deploy the db driver as a module, and configure via the data source via the web console. For the postgres driver, I directly downloaded the jar from

http://localhost:9990/console/index.html#deployment;deployment=postgresql-42.2.14.jar

so gave the 

 <resource-root path="postgresql-42.2.14.jar"/>

Using the jboss-cli method for creating the db driver as a module, 

wildfly/bin/jboss-cli.sh

ran as sudo, needed to put the entire command in one line

/subsystem=datasources/jdbc-driver=postgresql:add(driver-name=postgresql, driver-module-name=org.postgresql, driver-class-name=org.postgresql.Driver)

Outcome success.