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I was trying to debug my Linux boot process. If I set the default runlevel to 2 or 3, my system hangs without giving me a prompt. I was able to get to runlevel 1 via a kernel parameter, and ran all scripts in /etc/rc2.d via service ***** start/stop commands and it was fine. But if I do a telinit to runlevel 2 or 3, I can't see my shell prompt. So what is the difference between the two approaches?

I use SysVinit. Content of /etc/inittab (which I haven't modified):

id:3:initdefault:

# System initialization.
si::sysinit:/etc/rc.d/rc.sysinit

l0:0:wait:/etc/rc.d/rc 0
l1:1:wait:/etc/rc.d/rc 1
l2:2:wait:/etc/rc.d/rc 2
l3:3:wait:/etc/rc.d/rc 3
l4:4:wait:/etc/rc.d/rc 4
l5:5:wait:/etc/rc.d/rc 5
l6:6:wait:/etc/rc.d/rc 6

# Trap CTRL-ALT-DELETE
ca::ctrlaltdel:/sbin/shutdown -t3 -r now

# When our UPS tells us power has failed, assume we have a few minutes
# of power left.  Schedule a shutdown for 2 minutes from now.
# This does, of course, assume you have powerd installed and your
# UPS connected and working correctly.  
pf::powerfail:/sbin/shutdown -f -h +2 "Power Failure; System Shutting Down"

# If power was restored before the shutdown kicked in, cancel it.
pr:12345:powerokwait:/sbin/shutdown -c "Power Restored; Shutdown Cancelled"


# agetty on serial port
s0:2345:respawn:/sbin/agetty -L -i 9600 ttyS0 vt100
s1:2345:respawn:/sbin/agetty -L -i 9600 ttyS1 vt100

1:2345:respawn:/sbin/agetty 38400 tty1 linux

# Run xdm in runlevel 5
x:5:respawn:/etc/X11/prefdm -nodaemon

# Ask for password at single user prompt
~~:S:wait:/sbin/sulogin
  • I am having SysVinit. I dont have anything different in sysVinit. here is what I have pastebin.com/a85aGizM. Which log are you refering to ? can I set any flags to print logs ? – Rahin Aug 25 '14 at 12:38
  • Log messages are in files in /var/log. Look at the recently-modified files to see which ones might have interesting logs. Each log line has a date and time; the relevant log lines are the ones produced before and at the time your system hangs. – Gilles Aug 25 '14 at 12:59
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init does more than run the scripts in /etc/rc.d.

For one, it spawns mingetty or getty on each virtual terminal. Check that you haven't commented out, or have a typo near, the following lines:

# Run gettys in standard runlevels
1:2345:respawn:/sbin/mingetty tty1
2:2345:respawn:/sbin/mingetty tty2
3:2345:respawn:/sbin/mingetty tty3
4:2345:respawn:/sbin/mingetty tty4
5:2345:respawn:/sbin/mingetty tty5
6:2345:respawn:/sbin/mingetty tty6

(Note that I'm not in front of a RHEL/CentOS system at the moment, so there's no warranty!)

  • thanks for the response Gareth. yeah I didn't comment out them. I am able to get on Shell prompt when I set kernel to runlevel 1 so I assume my tty are spawned when I got into rc 1. which shouldn't be diff for other rcs – Rahin Aug 22 '14 at 11:43

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