KVM guests networking issues with no virbr0 and with vhost_net kernel modules loaded
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
OpenStack Compute (nova) |
Fix Released
|
Medium
|
Adam Gandelman | ||
Folsom |
Fix Released
|
Medium
|
Adam Gandelman | ||
Ubuntu Cloud Archive |
Fix Released
|
Undecided
|
Unassigned | ||
libvirt (Ubuntu) |
Won't Fix
|
Low
|
Unassigned | ||
nova (Ubuntu) |
Fix Released
|
High
|
Unassigned | ||
Quantal |
Fix Released
|
Undecided
|
Unassigned |
Bug Description
We've found that having vhost_net module and using bridged networking breaks DHCP and (some?) guests do not get an IP address.
The issue has been properly described in the following RH doc:
"11.2.1. Checksum correction for older DHCP clients"
Their workaround works in Precise too in fact.
Another workaround is to disable/unload the vhost_net module so new guests do not make use of it.
RH has fixed this stuff in libvirt apparently:
"This iptables rule is programmed automatically on the host when the server is started by libvirt, so no further action is required"
My apologies if this stuff does not belong to libvirt.
Some info from our environment:
compute-002:~# lsb_release -rd
Description: Ubuntu 12.04 LTS
Release: 12.04
compute-002:~# uname -a
Linux compute-002 3.2.0-27-generic #43-Ubuntu SMP Fri Jul 6 14:25:57 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
compute-002:~# dpkg -l|egrep "kvm|libvirt|
ii dnsmasq-base 2.59-4 Small caching DNS proxy and DHCP/TFTP server
ii dnsmasq-utils 2.59-4 Utilities for manipulating DHCP leases
ii dnsutils 1:9.8.1.
ii isc-dhcp-client 4.1.ESV-
ii isc-dhcp-common 4.1.ESV-
ii kvm-ipxe 1.0.0+git-
ii libdns81 1:9.8.1.
ii libnet-dns-perl 0.66-2ubuntu3 Perform DNS queries from a Perl script
ii libvirt-bin 0.9.8-2ubuntu17.2 programs for the libvirt library
ii libvirt0 0.9.8-2ubuntu17.2 library for interfacing with different virtualization systems
ii munin-libvirt-
ii nova-compute-kvm 2012.1+
ii python-libvirt 0.9.8-2ubuntu17.2 libvirt Python bindings
ii qemu-kvm 1.0+noroms-
We've also tested this with kernel 3.5 backport from Quantal:
Linux compute-002 3.5.0-6-generic #6~precise1-Ubuntu SMP Tue Jul 24 14:45:23 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
The guest is running Debian Squeeze:
debian-
Linux debian-
debian-
ii isc-dhcp-client 4.1.1-P1-
ii isc-dhcp-common 4.1.1-P1-
Related branches
summary: |
- KVM guests networking issues when bridge and vhost_net kernel modules - loaded + KVM guests networking issues with no virbr0 and with vhost_net kernel + modules loaded |
Changed in nova (Ubuntu): | |
status: | New → Confirmed |
importance: | Undecided → High |
tags: | added: folsom-rc-potential |
Changed in nova: | |
status: | New → Triaged |
importance: | Undecided → Medium |
tags: |
added: folsom-backport-potential removed: folsom-rc-potential |
Changed in nova: | |
assignee: | nobody → Jian Wen (wenjianhn) |
Changed in nova (Ubuntu): | |
assignee: | nobody → Jian Wen (wenjianhn) |
Changed in nova (Ubuntu): | |
assignee: | Jian Wen (wenjianhn) → nobody |
tags: | removed: folsom-backport-potential |
Changed in nova: | |
milestone: | none → grizzly-2 |
status: | Fix Committed → Fix Released |
Changed in nova: | |
milestone: | grizzly-2 → 2012.2.3 |
status: | Fix Released → Fix Committed |
Changed in nova: | |
milestone: | 2012.2.3 → grizzly-2 |
status: | Fix Committed → Fix Released |
Changed in nova (Ubuntu): | |
status: | Confirmed → Fix Released |
Changed in cloud-archive: | |
status: | New → Confirmed |
Changed in nova (Ubuntu Quantal): | |
status: | New → Confirmed |
Changed in nova (Ubuntu): | |
assignee: | nobody → Alex Vitola (vitola) |
assignee: | Alex Vitola (vitola) → nobody |
Changed in nova: | |
milestone: | grizzly-2 → 2013.1 |
tags: | added: cloud-archive |
Changed in cloud-archive: | |
status: | Confirmed → Fix Released |
Forgot to mention that the workaround isn't required when using openvswitch with the brcompat module since everything works as expected.