Michael, Thank you for taking a look at this and creating the new bug for changing the way libvirt virtualizes the hardware clock for Windows vs. Linux. I believe this to be the root cause for the bug defined here because of the way Windows handles DHCP renewals.
===DHCP=== As for DHCP, I am not sure anything is wrong with having a very short DHCP lease time of 120 sec as the default for nova. I was more curious what the reasoning behind this was. My understanding is that the DNSMasq default is 12 hours. I found this message also asking about the nova default - https://lists.launchpad.net/openstack/msg24200.html I also wanted to say that the DHCP lease time of 120 seconds does not really exacerbate the issue as I stated above. What is does is make the issue present faster. ==Windows DHCP lease renewal behavior=== This is my understanding of why we are seeing a lose of IP address for Windows 2008R2 (my reproducible issue) 1. Windows instance boots up on KVM with the hardware clock set to UTC (expects localtime) 2. The instance gets it's DHCP lease. (2 min) it logs the obtained time and expire time for the lease Ethernet adapter Local Area Connection: Connection-specific DNS Suffix . : novalocal Description . . . . . . . . . . . : Red Hat VirtIO Ethernet Adapter Physical Address. . . . . . . . . : FA-16-3E-23-D2-8E DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes Link-local IPv6 Address . . . . . : fe80::d420:7346:d258:ffa2%11(Preferred) IPv4 Address. . . . . . . . . . . : 192.168.200.25(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Lease Obtained. . . . . . . . . . : Thursday, September 26, 2013 5:17:06 PM Lease Expires . . . . . . . . . . : Thursday, September 26, 2013 5:47:06 PM Default Gateway . . . . . . . . . : 192.168.200.1 DHCP Server . . . . . . . . . . . : 192.168.200.1 DHCPv6 IAID . . . . . . . . . . . : 251270718 DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-19-D6-86-9A-FA-16-3E-23-D2-8E DNS Servers . . . . . . . . . . . : 192.168.200.1 NetBIOS over Tcpip. . . . . . . . : Enabled 3. NTP time sync happens, in my timezone PST (windows default), this sets the instance clock back 7 hours and updates the DHCP lease information as follows Ethernet adapter Local Area Connection: Connection-specific DNS Suffix . : novalocal Description . . . . . . . . . . . : Red Hat VirtIO Ethernet Adapter Physical Address. . . . . . . . . : FA-16-3E-23-D2-8E DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes Link-local IPv6 Address . . . . . : fe80::d420:7346:d258:ffa2%11(Preferred) IPv4 Address. . . . . . . . . . . : 192.168.200.25(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Lease Obtained. . . . . . . . . . : Monday, August 20, 1877 10:48:50 AM Lease Expires . . . . . . . . . . : Thursday, September 26, 2013 10:47:09 AM Default Gateway . . . . . . . . . : 192.168.200.1 DHCP Server . . . . . . . . . . . : 192.168.200.1 DHCPv6 IAID . . . . . . . . . . . : 251270718 DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-19-D6-86-9A-FA-16-3E-23-D2-8E DNS Servers . . . . . . . . . . . : 192.168.200.1 NetBIOS over Tcpip. . . . . . . . : Enabled 4. Windows now thinks it's DHCP lease obtained time is in the future and resets the obtained time to some time way in the past (year 1877) but adjusts the expire time to be the same amount of time from current time as it was before the NTP update. In the above example 30 min. 5. When the DHCP expire time is reached Windows releases the IP address and does not try and do a DHCP renewal. >From what I can tell this has been in issue in Windows for a very long time and and has not been addressed. In a hardware case this would be a one time problem until the time is updated and a manual DCHP renewal is done. But for unattended virtual machines the issue is much more of a problem. As the above message states Michael has created a new bug for the Widows issue and has already coded a fix! -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1026621 Title: nova-network gets release_fixed_ip events from someplace, but the database still keeps them associated with instances To manage notifications about this bug go to: https://bugs.launchpad.net/nova/+bug/1026621/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
