Comment 1 for bug 1397702

It appears that the Ubuntu packages are configuring this cleanup process for the DHCP and L3 agents already and have gone with an hourly interval.

/etc/cron.d# ls -al neutron-*
-rw-r--r-- 1 root root 319 Aug 12 12:15 neutron-dhcp-agent-netns-cleanup
-rw-r--r-- 1 root root 314 Aug 12 12:15 neutron-l3-agent-netns-cleanup

/etc/cron.d# cat neutron-*
# vim: set filetype=crontab:
# Periodically cleans Quantum's network namespaces on behalf of the Quantum
# DHCP agent.
30 * * * * neutron if [ -x /usr/bin/neutron-netns-cleanup ] ; then /usr/bin/neutron-netns-cleanup --config-file=/etc/neutron/neutron.conf --config-file=/etc/neutron/dhcp_agent.ini >/dev/null 2>&1; fi
# vim: set filetype=crontab:
# Periodically cleans Quantum's network namespaces on behalf of the Quantum
# L3 agent.
0 * * * * neutron if [ -x /usr/bin/neutron-netns-cleanup ] ; then /usr/bin/neutron-netns-cleanup --config-file=/etc/neutron/neutron.conf --config-file=/etc/neutron/l3_agent.ini >/dev/null 2>&1; fi