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Sunday, July 23, 2006

Ssh, Debian and "System bootup in progress - please wait"

I've solved this one before, but couldn't remember how, so here it is for posterity.

If an Debian ssh server is returning a "System bootup in progress - please wait" message to clients connecting during server boot, then the problem is that the server's /etc/default/rcS contains DELAYLOGIN=yes but needs to contain DELAYLOGIN=no.

The problem arises because setting DELAYLOGIN to yes causes /etc/init.d/, symlinked by /etc/rcS.d/, to create /etc/nologin, which causes a default ssh+PAM configuration (/etc/pam.d/ssh contains "auth required") to prevent logins. This file is removed late in the boot sequence by /etc/init.d/rmnologin, symlinked by /etc/rc2.d/S99rmnologin.

Another obvious approach is to remove pam_nologin from /etc/pam.d/ssh, but this would remove the ability to use /etc/nologin to block logins at all and, at least for systems under my control, there is no reason to delay login during boot.