hi, On 19.07.2012 09:28, Markus Fischer wrote: > Working sudo: > Jul 19 09:06:31 server sudo: theuser : TTY=pts/2 ; PWD=/tmp ; USER=root > ; COMMAND=/bin/ls > > sudo not working: > Jul 19 09:00:16 server sudo: theuser : TTY=unknown ; PWD=/tmp; USER=root > ; COMMAND=/bin/ls This, and one of the comment [1] on the SO question gave me a new direction to search for the problem: "I think it means that sudo is not the root cause of the problem; the apparent lack of a terminal is." I also realized the whole time I never described how I did enter the guest system to have this problems. I used "sudo vserver <vserver> exec su - theuser". With a small C program to get the current users tty: #include <unistd.h> #include <stdio.h> int main() { char *name = ttyname(0); printf("ttyname = '%s'\n", name); return 0; } I did the following tests (excutable put inside guest in /tmp/ttyname): theuser@host:~$ sudo vserver guest01 exec /tmp/ttyname ttyname = '(null)' theuser@host:~$ sudo vserver guest01 enter guest01:~# /tmp/ttyname ttyname = '/dev/pts/12' guest01:~# logout theuser@host:~$ sudo vserver guest01 exec su - theuser theuser@guest01:~$ /tmp/ttyname ttyname = '(null)' theuser@guest01:~$ logout theuser@host:~$ sudo vserver guest01 enter guest01:~# su - theuser theuser@guest01:~$ /tmp/ttyname ttyname = '/dev/pts/12' So, whenever I used "enter" to get in the system, my user has a valid tty. But when I use "exec", there's none. And I used "su - theuser" all the time to enter the system as my user directly. sudo was working whenever my user had a TTY but didn't worked when I had none. I also did another test: installed openssh inside guest01 and logged in via SSH; the result was that my user was having a tty and thus sudo worked too. I've then tested this on a Lenny guest system: theuser@host:~$ sudo vserver lenny01 exec su - theuser theuser@lenny01:~$ /tmp/ttyname ttyname = '/dev/pts/5' And apparently sudo was working there too. Now I wonder: what could be the reason that "exec" does give me a TTY in Lenny, but none in Squeeze? thx, - Markus [1] http://serverfault.com/questions/406010