Questions[xen](ubuntu)

I did some Google searches but failed to find anything for this problem. After installing 20.04 using the ZFS root option I installed Xen. When it rebooted it failed in initramfs with the error "No pool imported". I was able to boot the previous kernel. When I examined the /boot/grub/grub.cfg I found what looked like invalid "root=ZFS=" options like this:

"root=ZFS=/ROOT/ubuntu_xxxxxx"

The previous kernel that boots looks like this:

"root=ZFS=rpool/ROOT/ubuntu_xxxxxx"

After looking in /etc/default/grub and /etc/grub.d I was unable to figure out why they were different and how I could change it.

As a test saved a copy and edited /boot/grub/grub.cfg adding the rpool to each "root=ZFS=" line where rpool was missing. This time I was able to boot the Xen kernel.

Questions:

1. How do I fix the grub configuration with "root=ZFS=rpool/" so the normal tools like grub2-mkconfig/update-grub will work?

2. Is this a bug in 20.04, or did I do something wrong like the order I installed packages?

Problem 1: pv VMs running Ubuntu Linux would run but not connect through bridging until I added net.ipv4.ip_forward=1 to sysctl.conf (and rebooted). Unsure why I now need this but looking at issues with when sysctl.conf is run in startup (v. old issue) may provide a clue.

Problem 2 : (bigger issue) hvm VM running Windows 10 now refuses to start :

root@ap1:/etc/xen# cat zz.cfg
type = 'hvm'
name = 'win10'
memory = 4196
vcpus = 3
vif = ['bridge=xenbr0']
disk = ['phy:/dev/rootvg/win10-disk,hda,w','file:/backups/MLaptop/Windows10.iso,hdc:cdrom,r']
sdl = 0
vnc = 1
vncconsole = 1
vnclisten = ''
vncpasswd = ''
on_poweroff = 'destroy'
on_reboot   = 'restart'
on_crash    = 'restart'
localtime = 1
root@ap1:/etc/xen#  
root@ap1:/etc/xen# xl create zz.cfg
Parsing config from zz.cfg
libxl: error: libxl_dm.c:2426:device_model_spawn_outcome: Domain 18:domain 18 device model: spawn failed (rc=-3)
libxl: error: libxl_create.c:1563:domcreate_devmodel_started: Domain 18:device model did not start: -3
libxl: error: libxl_dm.c:2541:kill_device_model: Device Model already exited
libxl: error: libxl_domain.c:1034:libxl__destroy_domid: Domain 18:Non-existant domain
libxl: error: libxl_domain.c:993:domain_destroy_callback: Domain 18:Unable to destroy guest
libxl: error: libxl_domain.c:920:domain_destroy_cb: Domain 18:Destruction of domain failed

Does anyone have any clues as to why this might be failing now I have upgraded ?

More information :- en.service is not starting properly :

root@ap1:/etc/xen# systemctl status xen.service
● xen.service - LSB: Xen daemons
     Loaded: loaded (/etc/init.d/xen; generated)
     Active: failed (Result: exit-code) since Thu 2020-06-18 18:08:58 BST; 1min 58s ago
       Docs: man:systemd-sysv-generator(8)
    Process: 2378 ExecStart=/etc/init.d/xen start (code=exited, status=1/FAILURE)
      Tasks: 3 (limit: 19033)
     Memory: 30.5M
     CGroup: /system.slice/xen.service
             ├─2460 /usr/lib/xen-4.11/bin/oxenstored --pid-file /var/run/xenstore.pid
             └─2466 /usr/lib/xen-4.11/bin/xenconsoled --pid-file /var/run/xenconsoled.pid

Jun 18 18:08:58 apollo systemd[1]: Starting LSB: Xen daemons...
Jun 18 18:08:58 apollo xen[2378]:  * Starting Xen daemons
Jun 18 18:08:58 apollo xen[2469]: qemu-system-i386: -xen-domid 0: Option not supported for this target
Jun 18 18:08:58 apollo xen[2378]:    ...fail!
Jun 18 18:08:58 apollo systemd[1]: xen.service: Control process exited, code=exited, status=1/FAILURE
Jun 18 18:08:58 apollo systemd[1]: xen.service: Failed with result 'exit-code'.
Jun 18 18:08:58 apollo systemd[1]: Failed to start LSB: Xen daemons.

Dom0 wrong

xl list 
Name                                        ID   Mem VCPUs      State   Time(s)
(null)                                       0 31898     8     r-----      27.7

starting of domains end with error

xl create xen/xxx.cfg
Parsing config from xen/xxx.cfg
libxl: error: libxl_domain.c:1214:libxl__get_domid: failed to get own domid (domid)
libxl: error: libxl_device.c:1167:device_hotplug: Domain 4:Failed to get domid
libxl: error: libxl_domain.c:1214:libxl__get_domid: failed to get own domid (domid)
libxl: error: libxl_device.c:1167:device_hotplug: Domain 4:Failed to get domid
libxl: error: libxl_create.c:1299:domcreate_launch_dm: Domain 4:unable to add disk devices
libxl: error: libxl_domain.c:1214:libxl__get_domid: failed to get own domid (domid)
libxl: error: libxl_device.c:968:libxl__initiate_device_generic_remove: Domain 4:unable to get my domid
libxl: error: libxl_domain.c:1214:libxl__get_domid: failed to get own domid (domid)
libxl: error: libxl_domain.c:1214:libxl__get_domid: failed to get own domid (domid)
libxl: error: libxl_device.c:968:libxl__initiate_device_generic_remove: Domain 4:unable to get my domid
libxl: error: libxl_domain.c:1214:libxl__get_domid: failed to get own domid (domid)
libxl: error: libxl_domain.c:1107:devices_destroy_cb: Domain 4:libxl__devices_destroy failed
libxl: error: libxl_domain.c:1034:libxl__destroy_domid: Domain 4:Non-existant domain
libxl: error: libxl_domain.c:993:domain_destroy_callback: Domain 4:Unable to destroy guest
libxl: error: libxl_domain.c:920:domain_destroy_cb: Domain 4:Destruction of domain failed

I'm using Dell T410 server with Free version of Xenserver 7.4, i installed Ubuntu 18.04 VM all went well but i'm unable to adjust the resolution

from ubuntu settings, showing just 800X600, see attached image taken from VNC Viewer but look the same if i use XenCentre or Xen Orchestra console. i also installed Windows 10 vm and using Microsoft RDP App installed on my iMac to access and it working ok i can change any resolution from both the VM or the RDP App settings and have sound. but on the Ubuntu i think it picks up the Dell driver\HW with no option to change the resolution, as you see from the screen shot even the setting page doesn't fit the screen. in general i would like to do the same as windows VM, RDP with Microsoft if possible as preferred. I did manage to use VNC Viewer but resolution was the same. i did install the XS Guest tools on both the Windows and Ubuntu vms but didn't help with the resolution on ubuntu. i also researched online but only found outdated solution from 2016 XS V6.5 and Ubuntu 16.04 but no solution helped.

I use this setup as a home lab to learn about servers, linux CLI and VMs, so i wish to have a similar environment as a desktop.

my questions are :

1. how do i fix the resolution, do i need to install a XS or Ubuntu driver?

2. what you normally using in production and home lab environment to access the VM, RDP Client?

3. what RDP you recommend to get for best compatibility and environment as a desktop?

Thank you for your help

Yariv

Ubuntu settings showing on VNC

I am interested in trying out Xen;

• What packages do I need to install?
• How do I set up a DomU instance?