Red Hat Bugzilla – Bug 1251211
upgrading dnsmasq breaks neutron-dhcp-agent
Last modified: 2018-02-08 06:34:05 EST
neutron-dhcp-agent relies on a rootwrap KillFilter to determine whether or not it can kill an active dnsmasq process. The standard filter looks like this:
kill_dnsmasq: KillFilter, root, /sbin/dnsmasq, -9, -HUP
kill_dnsmasq_usr: KillFilter, root, /usr/sbin/dnsmasq, -9, -HUP
KillFilter operates by checking /proc/<pid>/exe against the path
specified in the filter. If the dnsmasq package on the system is
updated, rpm first renames the file, so it becomes something like:
And then deletes it, which leaves the corresponding /proc file looking
# ls -l /proc/23224/exe
lrwxrwxrwx. 1 root root 0 Aug 6 09:31 /proc/23224/exe -> /usr/sbin/dnsmasq;55c362c5 (deleted)
From this point on, the dhcp-agent process will be unable to kill that
Created attachment 1068675 [details]
patch accepted upstream
1. Created an network and a subnet
2. Checked dnsmasq PID
3. Ran: yum reinstall dnsmasq
4. ls -l /proc/48216/exe
lrwxrwxrwx. 1 root root 0 Dec 7 08:41 /proc/48216/exe -> /usr/sbin/dnsmasq;56652a46 (deleted)
5. Restarted dhcp agent: systemctl restart neutron-dhcp-agent
6. Verified dnsmasq PID has been changed.
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.
*** Bug 1368475 has been marked as a duplicate of this bug. ***
*** Bug 1368476 has been marked as a duplicate of this bug. ***