Best way to daemonize Java application on Linux

Question

Hi.

While I found this question being answered here on SW several times, I didn't find a concluding answer what is the best approach.

I'm not looking to use any external wrapper, as I found them launching the java process under a nice level lower then themselves which potentially lowers the performance, so it seems only the shell methods are left.

I so far found 3 different shell methods:

• start-stop-daemon
• RedHat daemon init.d function
• nohup on start / disown after start

What you people are using, and can recommend as the most reliable method?

Thanks.

Answer 1

You could try using screen (Launch screen, then launch the java program, then close[not quit] the screen)

Answer 2

I wouldn't rule out the external wrappers completely.
I have noticed some well respected software using the Tanuki Wrapper http://wrapper.tanukisoftware.org/.

This has the added advantage that the program can also be easily run as a windows service, with a consistent approach.

Answer 3

If I want to run an application in the background as a daemon, I do it like this:

nohup java -jar MyJar &

There's nothing particularly unreliable about it - nohup keeps it from receiving a SIGHUP when you disconnect, and & runs a process in the background.

Optionally, you can redirect the output to something other than nohup.out.

Answer 4

While the standard answer to this seems to be jsvc, I have been using djb's daemon tools to be a great way to make anything into a daemon.

I have java, python and a few shell scripts all running as daemons, with a simple way to start/stop them and great logging.

I've used to run daemontools itself as root on initctl as originally designed, but after a few months I decided to run it manually, under a normal user, and using svscan-start for nicer logging.

Answer 5

I would use the RedHat daemon init.d function. This allows you to have the application restart when the server does. Running nohup doesn't handle server restarts, etc.

Answer 6

I've used Akuma in the past, with great success. The fact that it's a Java library really makes things easier, embedding the functionality is trivial.