Re: can't start hvm with network

[Paul Leiber <paul@xxxxxxxxxxxxxxxx>]

Hi Kevin,

Am 17.03.2025 um 16:01 schrieb Kevin Wang:
> Installed ubuntu 24 onto E3-1225 v5 @ 3.30GHz (2C/4T) with one boring 
> sata disk, but I can't get the vm to start the ubuntu24 server installer iso
> cat >/etc/xen/auto/couch5.hvm <<'__EOF__'
> builder = "hvm"
> name = "couch5"
> memory = "10240"
> vcpus = 2
> #vif = ['']
> #vif = ['type=ioemu,model=e1000']
> #vif = ['type=ioemu,model=rtl8139']
> disk = ['phy:/dev/mapper/ubuntu--vg-couch--disk,hda,w','phy:/dev/mapper/ 
> ubuntu--
> vg-couch--home,hdb,w','file:/d/dmg/ubuntu-24.04-live-server- 
> amd64.iso,hdc:cdrom,
> r']
> #disk =
> disk = ['phy:/dev/mapper/ubuntu--vg-couch--disk,hda,w','phy:/dev/mapper/ 
> ubuntu--
> vg-couch--home,hdb,w']
> vnc = 1
> vncdisplay = 5901
> boot="dc"
> __EOF__
>
> As depicted here, commenting out all the vif= lines, it does boot (but a 
> server without a network isn't useful). But if I include any of the vif= 
> lines, it won't even start, I get:
> # xl create /etc/xen/auto/couch5.hvm
> Parsing config from /etc/xen/auto/couch5.hvm
> libxl: error: libxl_dm.c:3151:device_model_spawn_outcome: Domain 
> 7:domain 7 devi
> ce model: spawn failed (rc=-3)
> libxl: error: libxl_dm.c:3371:device_model_postconfig_done: Domain 
> 7:Post DM sta
> rtup configs failed, rc=-3
> libxl: error: libxl_create.c:1896:domcreate_devmodel_started: Domain 
> 7:device mo
> del did not start: -3
> libxl: error: libxl_aoutils.c:646:libxl__kill_xs_path: Device Model 
> already exit
> ed
> libxl: error: libxl_domain.c:1183:libxl__destroy_domid: Domain 7:Non- 
> existant do
> main
> libxl: error: libxl_domain.c:1137:domain_destroy_callback: Domain 
> 7:Unable to de
> stroy guest
> libxl: error: libxl_domain.c:1064:domain_destroy_cb: Domain 
> 7:Destruction of dom
> ain failed
Unfortunately, I don't have the knowledge to analyze the output you 
posted in detail. What comes to my mind, though: Did you set up a 
network bridge on Dom0? The default name of the bridge, if no other is 
given in the vif=... line (as in your examples), is xenbr0, as described 
in the docs [1].
My main guide is still the old wiki [2], the steps to create such a 
bridge are given there.
On another note: Why are you using HVM for setting up a linux DomU? I 
never tested Ubuntu myself, but for Debian (and most likely 
Debian-based) distributions, PV should the better option. Again, [2] 
shows how to install a Debian PV DomU, and the procedure is still 
working (of course, wheezy is a bit outdated and needs to be replaced, 
e. g. with bookworm). The section even mentions Ubuntu distributions, so 
it's probably worth to dig deeper there.
Paul

[1] 
https://xenbits.xenproject.org/docs/unstable/man/xl-network-configuration.5.html
[2] 
https://wiki.xenproject.org/wiki/Xen_Project_Beginners_Guide#Creating_a_Windows_HVM_(Hardware_Virtualized)_Guest