Running Tomcat9 with dedicated tomcat user: Startup fails with JAVA_HOME or 500 in localhost:8080

Question

I have just installed Apache Tomcat9 on my machine, following mostly these instructions , but I am really stuck with user management here.

My enviroment: Ubuntu 20.04, Java 11 ( There is only one alternative in link group java (providing /usr/bin/java): /usr/lib/jvm/java-11-oracle/bin/java ).

Few exceptions: I neither have JAVA_HOME , nor the java home directory in my PATH environment variable.

I also have created a symlink at /opt/tomcat/latest/ for pointing to the right folder for all tomcat files.

Now I want to let tomcat run as a service as user 'tomcat'.

This is how my tomcat.service file looks like:

[Unit]
Description=Tomcat 9 servlet container
After=network.target

[Service]
Type=forking

User=tomcat
Group=tomcat

Environment="JAVA_HOME=/usr/lib/jvm/java-11-oracle/bin/java"
# Environment="JAVA_OPTS=-Djava.security.egd=file:///dev/urandom -Djava.awt.headless=true"

Environment="CATALINA_BASE=/opt/tomcat/latest"
Environment="CATALINA_HOME=/opt/tomcat/latest"
Environment="CATALINA_PID=/opt/tomcat/latest/tomcat.pid"
# Environment="CATALINA_OPTS=-Xms512M -Xmx1024M -server -XX:+UseParallelGC"

ExecStart=/opt/tomcat/latest/bin/startup.sh
ExecStop=/opt/tomcat/latest/bin/shutdown.sh

[Install]
WantedBy=multi-user.target

Now, when I comment out the line for the JAVA_HOME environment variable, the startup of the tomcat service fails (journalctl -xe):

Okt 27 17:43:52 my-user startup.sh[7714]: Tomcat started.
Okt 27 17:43:52 my-user shutdown.sh[7737]: PID file found but either no matching process was found or the current user does not have permission to stop the process. Stop aborted.
Okt 27 17:43:52 my-user sudo[7690]: pam_unix(sudo:session): session closed for user root

So there is something running as root, what I don't get.

But when I comment out this line, tomcat runs happily, but on localhost:8080 I am getting this 500 :

Message org.apache.jasper.JasperException: java.lang.ClassNotFoundException: org.apache.jsp.index_jsp

or this 404

Message JSP file [/index.jsp] not found

It is similar like here and here .

I also did sudo chown -R tomcat /opt/tomcat/latest/work/Catalina/localhost , but this did not help.

Any help is appreciated.

Answer 1

Now it works and I'm going to list my changes here, but I'm not sure, which one was crucial and which was unnecessary.

1. JAVA_HOME in tomcat.service changed to: Environment="JAVA_HOME=/usr/lib/jvm/java-11-oracle"
2. CATALINA_PID in tomcat.service changed to: Environment="CATALINA_PID=/opt/tomcat/latest/temp/tomcat.pid"
3. give write access to other users to folders work, temp, logs, webapps . Sources here and here .
4. using this guide: https://www.interserver.net/tips/kb/install-apache-tomcat-on-ubuntu-18-04/