Let's say something like this is being returned when attempting to start one of your Tomcat instances.

'start' command failed. Unable to locate Runtime version '/opt/tomcat/tomcat-8.5.90.A.RELEASE

In this example, this has something to do with tomcat-8.5.90.A.RELEASE. Check out my article Tomcat RELEASE version. I once had this issue when the tomcat.version file being used by once of my instances mistakenly had both an old and the current RELEASE. This was resolved by updating the tomcat.version file to have the current RELEASE.

~]$ cat /opt/tomcat/profiles/devShrProducerService1/conf/tomcat.version
/opt/tomcat/tomcat-8.5.90.A.RELEASE
/opt/tomcat/tomcat-8.5.98.A.RELEASE