Note to self: <1Gb of RAM on a Dom0 Wheezy server causes kernel panics.
Using 2Gb of RAM seems to do the trick.
Tag: xen
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Xen: NAT and Bridging
Because dom0 was running NAT, and I needed bridging;
Debian network file (/etc/network/interfaces):
iface eth3 inet manual
auto xenbr0
iface xenbr0 inet static
bridge_ports eth3
address 10.19.86.1
broadcast 10.19.86.255
netmask 255.255.255.0
NAT is running on eth2, bridging on eth3 (/etc/xen/xend-config.sxp):
(network-script 'network-nat netdev=eth2')
Now, for the VM configs:
NAT:
vif = [ 'ip=172.16.1.12,mac=00:16:3E:5E:0D:1A' ]
Bridge:
vif = [ 'ip=85.12.6.178,mac=00:16:3E:1D:F5:6C,script=vif-bridge,bridge=xenbr0' ]
It’s magic and it works! 😉
vm3:/# iptables -t nat -A PREROUTING -p tcp -m tcp --dport 80 -j DNAT --to-destination 85.12.6.173:8180 WARNING: Could not open 'kernel/net/netfilter/x_tables.ko': No such file or directory FATAL: Could not open 'kernel/net/ipv4/netfilter/ip_tables.ko': No such file or directory iptables v1.4.2: can't initialize iptables table `filter': iptables who? (do you need to insmod?) Perhaps iptables or your kernel needs to be upgraded.
Solution:
vm3:/# depmod vm3:/# iptables -t nat -A PREROUTING -p tcp -m tcp --dport 80 -j DNAT --to-destination 85.12.6.173:8180
All ok 🙂
$ ssh vm3.rootspirit.com -l root [email protected]'s password: PTY allocation request failed on channel 0 stdin: is not a tty
Solution:
Kill the DomU (xm console *might* work, but somehow rarely works for me).
mkdir /tmp/disk mount /path/to/disk.img /tmp/disk chroot /tmp/disk /bin/bash
=> in chroot env
nano -w /etc/fstab
And add (though this is probably not needed):
none /dev/pts devpts defaults 0 0
And install udev:
apt-get install udev
Clean up, and restart DomU
exit umount /tmp/disk xm create /path/to/xen/vm.cfg
Should do the trick. 🙂
I had to start a new Xen domU this afternoon,
xm create vm#.domain
But this resulted in following error:
Error: Device 5632 (vbd) could not be connected.
Failed to find an unused loop device
Solution:
Create /etc/modprobe.d/local-loop.conf with this content:
options loop max_loop=64
Turn off all DomUs, yes, bummer. You’ll need to reload the loop module which won’t work if Xen is still using them. xm list should only display Domain-0.
modprobe -r loop && modprobe loop
And restart all DomUs. You can now create 32 (64/2 ~= # of DomUs; increase if you need more) DomUs.
You can check (before & after) the difference in loop back devices: ls -ls /dev | grep loop | wc -l