On Wed, Apr 3, 2019 at 5:55 PM Dominik Holler <dholler@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