OpenStack virtual machine DHCP gets no IP address to troubleshoot

Version: OpenStack Liberty Neutron DVR

Phenomenon:

1, in the virtual machine inside constantly dhclient

2. Catch the packet on the physical network card of the compute node to which the virtual machine belongs, and discover the DHCP broadcast packet issued by the virtual machine

3. On the physical network card of the NAT node (the node where the QDHCP resides) where the virtual machine belongs, the DHCP broadcast packet issued by the virtual machine is also found, that is, the packet was caught on BOND1:

Bridge br-intfail_mode:secure Port"sg-297691c4-9f"tag:1Interface"sg-297691c4-9f"type:internal Port"tap8a1db903-07"tag:2Interface"tap8a1db903-07"type:internal Port BR-intInterface BR-inttype:internal Port"qr-8d397111-81"tag:1Interface"qr-8d397111-81"type:internal Portint-br-VLAN Interfaceint-br-VLAN Type:Patchoptions: {Peer=phy-br-VLAN} Port"tap15d024ee-23"tag:1Interface"tap15d024ee-23"type:internal Bridge BR-ex Port BR-ex Interface BR-ex type:internal Port"qg-ab607114-19"Interface"qg-ab607114-19"type:internal Bridge BR-VLAN Port BR-VLAN Interface BR-VLAN type:internal Port PHY-br-VLAN Interface PHY-br-VLAN Type:Patchoptions: {Peer=int-br-VLAN} Port"Bond1"Interface"Bond1"ovs_version:"2.4.0"

4, but in the QDHCP network card tap15d024ee-23 can't catch the DHCP broadcast packet, see each OvS Bridge flow table did not find any problem, it is strange

Reason:

Later, with the help of colleagues, it was found that the BOND1 was added to a Linux bridge:

brctl Showbridge name     ID         STP enabled    interfacesbr0        8000. 1418774dd6a3    no        em1br1         8000. 90e2ba8465f2    No        bond1

Analysis:

The original bond1 was added to the Linux bridge, resulting in the appearance of being tied to Br-vlan, but it did not actually take effect, resulting in the upper Br-int not receiving the DHCP broadcast packet

Solve:

Unbind the Bond1 from the Linux bridge and rejoin the OvS bridge Br-vlan

OpenStack virtual machine DHCP gets no IP address to troubleshoot