Instances do not get IP from DHCP

Posted on

Hi All,

I am using OSP10 and have a network (provider) where I use OVS (vlan type network) and i enabled dhcp to allocate IPs to the instance. When the instance comes up, I see that it sends a request and controller receives it through the bridge that it has the Openstack internal networks, but if I check the dhcp namespace for that network, I dont see any packets coming in or going out.

[root@tt-overcloud-controller-0 neutron]# ip netns exec qdhcp-2248b2cb-2e1a-4c41-864d-599fd9700915 ifconfig
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10
loop txqueuelen 1 (Local Loopback)
RX packets 4 bytes 336 (336.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 4 bytes 336 (336.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

tap35bb5488-72: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 8996
inet 10.248.242.27 netmask 255.255.255.224 broadcast 10.248.242.31
inet6 fe80::f816:3eff:fe86:38 prefixlen 64 scopeid 0x20
ether fa:16:3e:86:00:38 txqueuelen 1000 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 5 bytes 438 (438.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

ip netns exec qdhcp-2248b2cb-2e1a-4c41-864d-599fd9700915 tcpdump -ln -i tap35bb5488-72
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on tap35bb5488-72, link-type EN10MB (Ethernet), capture size 262144 bytes
^C
0 packets captured
0 packets received by filter
0 packets dropped by kernel
[root@tt-overcloud-controller-0 neutron]# neutron agent-list
An auth plugin is required to fetch a token

The DHCP agent works normally and I see it always UP/alive but
when I try to enable dnsmasq.logs in the dhcp-agent config to understand what's going on, the dhcp agent cannot start saying below:

Apr 20 13:34:46 tt-overcloud-controller-0 dnsmasq[559228]: cannot open log /var/log/neutron/dnsmasq.log: Permission denied

So my main issue is why my instances cannot get an IP from DHCP and the child issue is enabling the dnsmasq logging

My deployment was via OSP Director. I havent done anything special to configure dhcp but I believe I dont need to. OR do I?

Any ideas?
Burak

BD

Responses