http://serverfault.com/questions/127419/how-to-get-a-cli-for-a-virtual-machine-on-xenserver
Example:
Say I want to connect to knox (a linux domU)
[root@xen01 ~]# xe vm-list
uuid ( RO) : 8258a6d4-23f6-003d-30d7-65bd13086863
name-label ( RW): knox
power-state ( RO): running
uuid ( RO) : 1a191475-a99d-7a77-6550-b30a0038fd92
name-label ( RW): Windows Server 2008 SP2 x86
power-state ( RO): halted
uuid ( RO) : ffd95724-d818-4f15-b4b4-159b7ff41df4
name-label ( RW): Control domain on host: xen01
power-state ( RO): running
Now get domain ids
[root@xen01 ~]# list_domains
id | uuid | state
0 | ffd95724-d818-4f15-b4b4-159b7ff41df4 | R
1 | bc150966-8c21-7ad9-c329-839d5823041d | B H
7 | baa3699b-95dd-eea0-ccc4-51e8972857f5 | B
11 | 8258a6d4-23f6-003d-30d7-65bd13086863 | B
You can see the domain ID that matches the UUID of knox is 11. So we use xenconsole
[root@xen01 ~]# /usr/lib/xen/bin/xenconsole 11
(press enter)
You have new mail in /var/spool/mail/root
[root@knox ~]#
