Comment 2 for bug 1660305

http://logs.openstack.org/09/418609/11/check/gate-tempest-dsvm-neutron-dvr-multinode-full-ubuntu-xenial-nv/9de3c0d/logs/subnode-2/screen-q-l3.txt.gz

privsep fails to start in l3 agent on compute node:

2017-01-24 04:19:01.586 13486 WARNING oslo.privsep.daemon [-] privsep log: sudo: no tty present and no askpass program specified
2017-01-24 04:19:01.592 13486 CRITICAL oslo.privsep.daemon [-] privsep helper command exited non-zero (1)
2017-01-24 04:19:01.593 13486 ERROR neutron.agent.l3.dvr_local_router [-] DVR: Failed updating arp entry

hence no routers can be processed on compute node.