[ovirt-devel] Re: Suspend resume and DHCP
On Wed, Apr 3, 2019 at 5:55 PM Dominik Holler <dholler(a)redhat.com> wrote:
Hello,
would you help me to understand if the dhcp client in an oVirt guest
should refresh his dhcp configuration after the guest is resumed?
If this is the case, how this should be triggered?
The reason why I ask is, that if a VM suspends on a first host, and
resumes on a second one, libvirt's nwfilter losses the IP address of
the guest, which means that the guest is not reachable until he
refreshes dhcp config, if the clean-traffic filter with
CTRL_IP_LEARNING=dhcp is used.
Do you know if libvirt's nwfilter transfers the IP address during live
migration? I'd suspect that you'd have the same problem there.
I believe that libvirt should handle this in BOTH cases (live
migration and suspend/resume). It should store the learned IP in the
suspended data and revive it on the target host.
Calling in +Laine Stump for his opinion.
Regardless of this, I think that a guest should request a dhcp renewal
upon resume. After all, it may have been suspended for few years.
This can be done if we add a "resumed" notification to the guest
agent, and have libvvirt/Vdsm trigger after resume.
This scenario might happen in OST basic-suite-master and
basic-suite-4.3 in verify_suspend_resume_vm0.
I suspect that we can work around this bug in OST by requesting Engine
to resume vm0 on the same host it was suspended from
> Thanks
> Dominik