Cannot Connect to the Internet inside XenServer VM

Question

Recently I've been trying to learn how to use XenServer for another project of mine, whereby I need to be able to programmatically launch and destroy virtual machines from the command line.

As this is primarily a personal project, I haven't been able to purchase any real hardware and so I am currently running XenServer inside Oracle VirtualBox in bridged mode, without HVM, and so I am only able to launch 32-bit Linux VMs (I think).

At present, I run the following commands which execute successfully launching a virtual machine and putting it in the running state:

xe vm-install template=<the_ubuntu_precise_template_32bit> new-name-label=UbuntuVM sr-uuid=<local_storage_uuid>

xe network-list bridge=xenbr0 --minimal

xe vif-create vm-uuid=<vm_uuid> network-uuid=<network_uuid (previous command output)> mac=random device=0

xe vm-param-set uuid=<vm_uuid> other-config:install-repository=http://archive.ubuntu.com/ubuntu/dists/precise-updates/

xe vm-start uuid=<vm_uuid>

Once I run these commands there is a brief pause whilst I assume the net installer is downloaded and then the vm goes into running mode. (as is displayed when I run xe vm-list)

Then if I run xe console uuid=<vm_uuid>, I enter into the ubuntu installer, however every time the installer fails.

In the setup, everything seems to be working fine, IPv6 is correctly setup, and I double checked on my router, finding that the VM is correctly registered as a connected device. Then it asks for me to chose a mirror, but upon selection of a mirror, the installer starts 'downloading the release files' and a progress bar begins which shoots from 0% to 100% over the course of a few minutes, returning the error message: BAD MIRROR. I have tried different mirrors, however I found that none worked, and threw the same error.

Finally, I launched into the Shell included in the installer, and ran the following commands to test whether my internet connection worked:

ping 127.0.0.1 = 127.0.0.1 is alive!

ping 192.168.0.31 (the XenServer host) = 192.168.0.31 is alive!

ping 192.168.0.1 (my router) returns nothing however.

ping 8.8.8.8 also returns nothing.

From this is seems that the VM doesn't have access to the internet, and so I believe that there might be some issue with the network I assigned to the VM?

On the XenServer host I ran ifconfig and received the following information:

eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        ether 08:00:27:6f:51:a0  txqueuelen 1000  (Ethernet)
        RX packets 246  bytes 47076 (45.9 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 93  bytes 10473 (10.2 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        loop  txqueuelen 0  (Local Loopback)
        RX packets 16  bytes 4602 (4.4 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 16  bytes 4602 (4.4 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

xenbr0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.0.31  netmask 255.255.255.0  broadcast 192.168.0.255
        ether 08:00:27:6f:51:a0  txqueuelen 0  (Ethernet)
        RX packets 274  bytes 48924 (47.7 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 121  bytes 13909 (13.5 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

For good measure I also ran netstat -rn on the XenServer host and received the following output:

Kernel IP routing table

Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
0.0.0.0         192.168.0.1     0.0.0.0         UG        0 0          0 xenbr0
192.168.0.0     0.0.0.0         255.255.255.0   U         0 0          0 xenbr0

Any help would be greatly appreciated,

Cheers, Oli

score 1 · Answer 1 · answered Aug 24 '16 at 13:27

1

Ok, so it turns out that after a very large faff, you cannot run XenServer in VirtualBox using a Bridged Adapter, and at the same time provide access to VMs. Therefore as a quick fix for this, I resorted to using NAT and port forwarding SSH to my host (my MacBook) so that I was able to connect. I'm not entirely sure as the reason why I wasn't able to run XenServer in Bridged Mode but I guess it has something to do with xenbr0 not being setup correctly and quite frankly for a test machine to see if I am able to launch a VM, I cannot be bothered to reconfigure it, and am unsure whether it is even possible to do so.

So, as a quick fix to all you VirtualBoxers, run XenServer in NAT as it doesn't work in bridged adapter mode.

Hope this helps anyone with a headache,

Oli.

answered Aug 24 '16 at 13:27

Oli Callaghan

141
2
7

I would also add that you must use Nat Network mode, AND enable promiscuous mode (in Advanced setting). Otherwise, traffic doesn't flow for VMs created in xen. – Fan Dec 01 '16 at 23:28
I just wasted a half day with this same issue until I've found your answer. The first caveat is that the HVM is not avaliable inside VirtualBox. It tells me no Windows guests possible. No problem, then I use a linux. I try to install it, and it says no HWM available. Dear Xen, you've said no Windows, now you say no Linux either? Then I fiddled until I could install CentOS 6, but at the first boot, it just simply restarted in loop. Turned out that the allocated RAM was not enough... Then I reached the no internet in VM problem and *poof* my day is over without any meaningful work... – csadam Jan 18 '18 at 21:50

Cannot Connect to the Internet inside XenServer VM

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