unit.service failed because the control process exited with error code. What does this error mean?

Question

I am trying to start a script in /etc/init.d in ubuntu 16.04. but it gives me an error. I am able to execute each step in that (scheduler_slave) unit manually. However it fails while executing through the script.

Could anyone explain what is the meaning of the below error/

I am totally a newbie to this field and trying to figure out why this error comes. Please let me know if I missed any detail.

command:

sudo /etc/init.d/scheduler_slave start

error:

[....] Starting scheduler_slave (via systemctl): 
scheduler_slave.serviceJob for scheduler_slave.service failed because 
the control process exited with error code. See "systemctl status 
scheduler_slave.service" and "journalctl -xe" for details.
failed! 

systemctl status scheduler_slave.service

● scheduler_slave.service - LSB: Start scheduler slave at boot
     Loaded: loaded (/etc/init.d/scheduler_slave; bad; vendor preset: 
    enabled)
     Active: failed (Result: exit-code) since Mon 2018-03-12 13:03:39 IST; 
    1h 26min ago
     Docs: man:systemd-sysv-generator(8)
     Process: 7315 ExecStart=/etc/init.d/scheduler_slave start 
    (code=exited, status=203/EXEC)

sudo journalctl -xe

    -- A new session with the ID 80 has been created for the user ubuntu.
--
-- The leading process of the session is 7377.
Mar 12 14:29:24 ubuntu systemd[1]: Started Session 80 of user ubuntu.
-- Subject: Unit session-80.scope has finished start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit session-80.scope has finished starting up.
--
-- The start-up result is done.
Mar 12 14:32:56 ubuntu sudo[7547]:   ubuntu : TTY=pts/1 ; PWD=/home/ubuntu ; USER=root ; COMMAND=/bin/journalctl -xe
Mar 12 14:32:56 ubuntu sudo[7547]: pam_unix(sudo:session): session opened for user root by ubuntu(uid=0)
Mar 12 14:34:29 ubuntu sudo[7547]: pam_unix(sudo:session): session closed for user root
Mar 12 14:34:36 ubuntu sudo[7551]:   ubuntu : TTY=pts/1 ; PWD=/home/ubuntu ; USER=root ; COMMAND=/etc/init.d/scheduler_slave start
Mar 12 14:34:36 ubuntu sudo[7551]: pam_unix(sudo:session): session opened for user root by ubuntu(uid=0)
Mar 12 14:34:36 ubuntu systemd[1]: Starting LSB: Start scheduler slave at boot...
-- Subject: Unit scheduler_slave.service has begun start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit scheduler_slave.service has begun starting up.
Mar 12 14:34:36 ubuntu systemd[7562]: scheduler_slave.service: Failed at step EXEC spawning /etc/init.d/scheduler_slave: Exec format error
-- Subject: Process /etc/init.d/scheduler_slave could not be executed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- The process /etc/init.d/scheduler_slave could not be executed and failed.
--
-- The error number returned by this process is 8.
Mar 12 14:34:36 ubuntu systemd[1]: scheduler_slave.service: Control process exited, code=exited status=203
Mar 12 14:34:36 ubuntu systemd[1]: Failed to start LSB: Start scheduler slave at boot.
-- Subject: Unit scheduler_slave.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit scheduler_slave.service has failed.
--
-- The result is failed.
Mar 12 14:34:36 ubuntu systemd[1]: scheduler_slave.service: Unit entered failed state.
Mar 12 14:34:36 ubuntu systemd[1]: scheduler_slave.service: Failed with result 'exit-code'.
Mar 12 14:34:36 ubuntu sudo[7551]: pam_unix(sudo:session): session closed for user root
Mar 12 14:34:47 ubuntu sudo[7594]:   ubuntu : TTY=pts/1 ; PWD=/home/ubuntu ; USER=root ; COMMAND=/bin/journalctl -xe
Mar 12 14:34:47 ubuntu sudo[7594]: pam_unix(sudo:session): session opened for user root by ubuntu(uid=0)

Solution

The error you pasted is "Exec format error".

There are already a number of possible causes for "Exec format error" documented in the Stack Exchange network. I recommend reviewing that answer.

Also, if you can, avoid mixing systemd config files with legacy "sysVinit" scrypts in /etc/init.d. They can work together, but it makes problems harder to be debug. I recommend using exclusively systemd if possible.

Comments

[muru]

status=203/EXEC means the file could not be executed (doesn't exist? permission denied?). What does your init script try to execute?

[Praneetha]

init script has commands to run 3 other ruby scripts.And I am able to run those 3 ruby scripts manually.

[Praneetha]

thanks! will let you know if the error still persists.