Why Tomcat can not delete its pid file?

[paperring]

I installed Tomcat 9.0.37 on Ubuntu 18.04 VPS. Problem is after starting the Tomcat, it makes inactive itself automatically after sometimes and when active state gives a status notification like this:



Starting Tomcat 9 servlet container...
Sep 14 14:23:55 ubuntuServer startup.sh[23466]: Existing PID file found during start.
Sep 14 14:23:55 ubuntuServer startup.sh[23466]: Removing/clearing stale PID file.
Sep 14 14:23:55 ubuntuServer startup.sh[23466]: Tomcat started.
Sep 14 14:23:55 ubuntuServer systemd[1]: Started Tomcat 9 servlet container.




I thougth that Tomcat can not delete its pid file when restarting but I can't find where the problem is. Here is "/etc/systemd/system/tomcat.service" file ("latest" directory is a symbolic link which will point tomcat installation directory):



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

[Service]

Type=forking
User=tomcat
Group=tomcat
Environment="JAVA_HOME=/opt/jdk/jdk1.8.0_261"
Environment="JAVA_OPTS=-Djava.security.egd=file:///dev/urandom"


Environment="CATALINA_BASE=/opt/tomcat/latest"
Environment="CATALINA_HOME=/opt/tomcat/latest"

Environment="CATALINA_PID=/opt/tomcat/latest/temp/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


Any idea to solving this?

[TheFu]

.system files run as root, then fork over to a different userid, tomcat, in this situation. There are reasons.

I suspect you might be confusing the process, euid and egid.
What are the file permissions for /opt/tomcat/latest/temp/tomcat.pid? Owner, group, and full permissions?
What are the directory permissions for /opt/tomcat/latest/temp/? Owner, group, and full permissions?

The parent directory permissions control whether a file inside can be deleted. This is Unix 101 stuff.

I know very little about Java anymore. Have avoided it since around 1996. Still waiting for the promises made to become true about that language and environment.

[paperring]

Directory permissions:

drwxrwx--- 2 tomcat tomcat 4096 Sep 14 21:27 temp
File permissions:

-rw-r----- 1 tomcat tomcat 5 Sep 14 21:27 tomcat.pid
Everytime I execute shutdown.sh and startup.sh tomcat.pid file permissions change as above and gives
Existing PID file found during start. status message.
I see your reasons you're right. I'am learning spring framework and I'am just practicing on servlet api.