Why does sudo command take long to execute?

Solution 1:

I asked this question over on SO and it got moved here. That said I no longer have the ability to edit the question as if I owned it, or even accept the correct answer, but this turned out to be the true reason why and how to solve it:

Found here User "rohandhruva" on there gives the right answer:

This happens if you change the hostname during the install process.

To solve the problem, edit the file /etc/hosts localhost localhost.localdomain localhost4 localhost4.localdomain4 <ADD_YOURS_HERE> 
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6 <ADD_YOURS_HERE>

Solution 2:

Check that your syslog daemon is working correctly; this caused the issue for me.

Run the following command

logger 'Hello world'
  1. Does the command return within a reasonable amount of time?

  2. Does 'Hello world' show up in /var/log/syslog?

If this is not the case, the syslog daemon has crashed. Restarting it should fix your problem.

Solution 3:

Is one of the files/directories it needs to read on a networked mount, or is it somehow triggering reading from a slow usb device? Try strace and see where it's slow; if it goes by too fast, do

sudo strace -r -o trace.log sudo echo hi

Each line will start with the time taken since entering the previous syscall.

(The initial sudo seems to be necessary; I don't know how much that will perturb the results.)

Solution 4:

I recently found that I had the same problem. There had been no sudo delay and then all of a sudden, about a 10-20 second delay. I determined the specific issue using:

 1. chmod u+s /usr/sbin/strace  (as the root user)

As yourself:

 1. sudo -K
 2. strace sudo /bin/tcsh

And then find where the system calls are hanging.

In MY case, I found that it was hanging on a DNS translation, apparently one of the DNSen in my list on /etc/resolv.conf was very buzy or gone bad. So I changed the resolution order and poof things worked quickly again.

Solution 5:

I'm not sure about Fedora, but I've used other systems where sudo would check where you're logged in from, which if your DNS isn't set up well can take ages to timeout. This can also be seen when SSH'ing in to the machine - it takes ages to come up with a prompt.