[Xen-devel] xen4.2 + qemu-upstream domain rename partial failure (& migration)

[Alex Bligh <alex@xxxxxxxxxxx>]

I am seeing a problem with domain renames which I think affects everything
running with the upstream qemu xen DM.

If I create a domain, and then rename it, it renames in the xenstore, but
it does not rename in qemu. This means that (interalia) the name on a VNC
connection is incorrect. I am seeing this with a migration (where a
libxl_domain_rename is done from "name--incoming" to "name" is done
close to the end of the migration), but it also seems to happen with
"xl rename" from the command line (see below for how to replicate).

So, to be clear, it's renaming in xenstore (and xl list) but not the
rename is not being transmitted to qemu to affect (e.g.) the vnc name.
Hence after a migration, "--incoming" gets stuck on the end of the VNC
name even when a migration is successful.

I don't really understand how this is meant to work. Should something
be setting a watch on the xenstore "name" element? Or should libxl be
issuing QMP command on the name change?

Or is this just doomed to fail? In which case the name passed as -name
to the QEMU command line should probably be the original name, not the
name with "--incoming" on on a migration, and 'xl rename' is just going
to fail to change it.

Code inspection suggests this is no different in xen-unstable but I
haven't tried it.

--
Alex Bligh


root@ubuntu:~# xl create /root/xlcreate-qcow.conf
Parsing config from /root/xlcreate-qcow.conf
xc: info: VIRTUAL MEMORY ARRANGEMENT:
ÂLoader: ÂÂÂÂÂÂÂ0000000000100000->000000000019db88
ÂTOTAL: ÂÂÂÂÂÂÂÂ0000000000000000->00000000bf800000
ÂENTRY ADDRESS: 0000000000100000
xc: info: PHYSICAL MEMORY ALLOCATION:
Â4KB PAGES: 0x0000000000000200
Â2MB PAGES: 0x00000000000003fb
Â1GB PAGES: 0x0000000000000001
Daemon running with PID 6946
root@ubuntu:~# xl list
Name 
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂID 
ÂÂMem VCPUs	State	Time(s)
Domain-0 
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ0 
Â5049 ÂÂÂÂ2 ÂÂÂÂr----- ÂÂÂ1682.6
Irrelevant 
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ5 
Â6912 ÂÂÂÂ2 ÂÂÂÂ-b---- ÂÂÂ2576.5
InitialName 
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ6 Â3072 
ÂÂÂÂ2 ÂÂÂÂr----- ÂÂÂÂÂÂ8.8
root@ubuntu:~#

InitialName is the newly created domain.

root@ubuntu:~# ps aux | grep qemu

root ÂÂÂÂÂ6817 Â9.9 Â0.5 410360 26944 ? ÂÂÂÂÂÂÂSLsl 10:00 
ÂÂ0:09 /usr/lib/xen/bin/qemu-system-i386 -xen-domid 6 -chardev 
socket,id=libxl-cmd,path=/var/run/xen/qmp-libxl-6,server,nowait -mon 
chardev=libxl-cmd,mode=control -name InitialName -vnc 0.0.0.0:0,password 
-serial pty -vga cirrus -boot order=cda -smp 2,maxcpus=2 -device 
rtl8139,id=nic0,netdev=net0,mac=00:16:3e:e9:96:a8 -netdev 
type=tap,id=net0,ifname=vif6.0-emu,script=no,downscript=no -M xenfv -m 3064 
-drive 
file=/root/test.qcow2,if=ide,index=0,media=disk,format=qcow2,cache=writeback
root@ubuntu:~# xl rename 6 NewName
root@ubuntu:~# xl list
Name 
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂID 
ÂÂMem VCPUs	State	Time(s)
Domain-0 
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ0 
Â5049 ÂÂÂÂ2 ÂÂÂÂr----- ÂÂÂ1688.0
Irrelevant 
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ5 
Â6912 ÂÂÂÂ2 ÂÂÂÂ-b---- ÂÂÂ2580.4
NewName 
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ6 
Â3072 ÂÂÂÂ2 ÂÂÂÂ-b---- ÂÂÂÂÂ16.2
root@ubuntu:~# ps aux | grep qemu

root ÂÂÂÂÂ6817 Â8.1 Â0.5 410360 26944 ? ÂÂÂÂÂÂÂSLsl 10:00 
ÂÂ0:09 /usr/lib/xen/bin/qemu-system-i386 -xen-domid 6 -chardev 
socket,id=libxl-cmd,path=/var/run/xen/qmp-libxl-6,server,nowait -mon 
chardev=libxl-cmd,mode=control -name InitialName -vnc 0.0.0.0:0,password 
-serial pty -vga cirrus -boot order=cda -smp 2,maxcpus=2 -device 
rtl8139,id=nic0,netdev=net0,mac=00:16:3e:e9:96:a8 -netdev 
type=tap,id=net0,ifname=vif6.0-emu,script=no,downscript=no -M xenfv -m 3064 
-drive 
file=/root/test.qcow2,if=ide,index=0,media=disk,format=qcow2,cache=writeback



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel