Apparmor results in denying operation mknod for isc-dhcp-server

Thank you for using Ubuntu and filing a bug. By default, isc-dhcp-server's dhcpd will use /var/run/dhcp-server/dhcpd.pid, and this is allowed by the AppArmor profile. /etc/dhcpd.conf is also a non-default (though common outside of Ubuntu) location for the configuration file, so it appears you are using non-default configuration options (and therefore either need to adjust the AppArmor profile, or your configuration). Can you attach your /etc/dhcpd.conf file?

Hi Jamie,
Apology but i think this is not a bug, as i reported earlier.

The dhcpd.conf is being written by cobbler and that is why i was getting the Apparmor error.
Maybe we need to write a policy in Apparmor to allow the writing of /etc/cobbler/dhcp.template to /etc/dhcpd.conf :)

The permission error is due to the fact that dhcpd is being started with no arguments and attempting to create the .pid file in a directory it does not have access to. If instead, it is started as 'dhcpd -pf /var/run/dhcp-server/dhcpd.pid' it will succeed in creating its pid file and reading its default configuration /etc/dhcpd.conf (regardless of how dhcpd.conf was generated). The isc-dhcp-server init script takes care of these details and ensures the daemon is being started with the correct defaults (which also use /etc/dhcp/dhcpd.conf instead of /etc/dhcpd.conf)

Furthermore, the location of the Cobbler generated dhcpd.conf appears to not even be configurable anymore (since natty, at least). Instead, cobbler contains logic to determine where to put this based on distro and relies on distro supplied init scripts to the rest:

/usr/lib/python2.7/dist-packages/cobbler/utils.py:

def dhcpconf_location(api):
    version = api.os_version
    if version[0] in [ "redhat", "centos" ] and version[1] < 6:
        return "/etc/dhcpd.conf"
    elif version[0] in [ "fedora" ] and version[1] < 11:
        return "/etc/dhcpd.conf"
    else:
        return "/etc/dhcp/dhcpd.conf"

I have the issue with last week's isc-dhcp-server, ubuntu 12.04 LTS.

That package uses /var/run/dhcpd.run and does NOT use the sub-directory /var/run/dhcp-server (as claimed by Jamie Strandboge (jdstrand)).

The solution for me was to add a symbolic link (as root):
ln -s /var/run/dhcp-server/dhcpd.pid /var/run/dhcpd.pid
Now everything works fine!

My network configuration fails on the same pro problem and the symbolic link
ln -s /var/run/dhcp-server/dhcpd.pid /var/run/dhcpd.pid

workaround does not work for me.

I consider this bug *very* severe. I can't use any network features without runing a manual fix afer *every* single boot
I am mostly using Windows 7 now so this a follow up of bug #1 of Ubuntu!

The comment above saying that dhcp should be started correctly put me on the track
I had to change /etc/init.d/isc-dhcp-server script
changing DHCPDPID to /var/run/dhcp3-server/dhcpd.pid

from /var/run/dpcpd.pid

/var/run can not be written to from the daemon user

Wolfgang, which version of Ubuntu are you using? At a fresh install of Ubuntu 12.04 LTS (without the transitional dhcp3-server package installed) the directory /var/run/dhcp3-server/ does not exist.

For you, instead of patching the isc-dhcp-server script,
ln -s /var/run/dhcp3-server/dhcpd.pid /var/run/dhcpd.pid
should have done the trick.