Xen Cheat Sheet Edit Cheat Sheet

Xen

• Test if you are running a Xen kernel:

  cat /sys/hypervisor/properties/capabilities 
  

• Xen vs. Xen Server

• Xen - Commands

  xm list           # List all domains
  xm list vm1       # List status of a single VM
  xm list vm1 -l    # Details for a VM 
  xm create vm1     # Starts/Creates a VM
  xm reboot vm1     
  xm shutdown vm1
  xm destroy vm1
  
  xm network-list vm1
  
  xm console vm1     # Open console to VM (escape like telnet)
  
  xm info            # HV infos
  xm top             # Monitor HV and domains
  xm log             # View HV log
  
  xm dominfo
  xm vcpuinfo
  xm nodeinfo
  

• Ensure guest auto start on boot:

  ln -s /etc/xen/<instance> /etc/xen/auto/<instance>
  

• Find out which dom0 you are on:

  dmesg | grep "command line"
  
  # Should give you something like:
  #
  # Kernel command line:  ro root=/dev/VolGroup00/LogVol00 console=xvc0 hostip=10.0.0.17
  #
  # Where "hostip" is the IP of the hypervisor
  

• Find out which IP a VM has:

  # Grep and resolve MAC:
  xm list -l <VM name> | grep mac
  arp -a | grep -i <MAC address>
  

Xen Server

• Feature Matrix XenServer Free vs. Enterprise: Whats the difference and what features are provided by “xe” what “xm” doesn’t have…
• XenServer GUI Comparison Free vs. Enterprise

• Xen Server - Hanging Operation on Shutdown: This happens when for example a reboot doesn’t work and you want to perform a shutdown to quickly restore an unresponding VM. The first task (reboot) is ineffective and won’t complete and thereby will block the second task (the shutdown). Destroying the VM domain solves the issue:

  xe vm-list                                          # 1. Resolve VM UUID with 
  list_domains | grep <uuid>                          # 2. Get Domain Id
  /opt/xensource/debug/destroy_domain -domid <domid>  # 3. Kill Domain Id
  xe vm-reboot uuid=<uuid> force=true                 # 4. Force Action
  

  An alternative is described here and involves determining the hanging task and cancelling it:

  xe task-list                          # Get task uid
  xe task-cancel uuid=<task uuid>       # And cancel it
  

• XenServer - Add Another Physical Disk:

  xe host-list                         # to get host UUID
  xe sr-create host-uuid=<host UUID> shared=false type=lvm \
     content-type=user device-config:device=/dev/sdb1 name-label="Another disk"
  

• XenServer - VM Paravirtualization: How to configure a single VM to be paravirtualized:

  # Configure boot
  xe vm-param-set uuid=<VM UUID> HVM-boot-policy=''
  xe vm-param-set uuid=<VM UUID> PV-bootloader=pygrub
  
  # Configure console to work in XenCenter
  xe vm-param-set uuid=<VM UUID> PV-args="console=tty0 xencons=tty"
  
  # Determine boot disk and set it bootable for XenServer
  xe vbd-list vm-uuid=$VMUUID type=Disk
  xe vbd-param-set uuid=<disk UUID> bootable=true
  

• XenServer - Configure LACP Bonding: When you want to run your XenServer with interface trunking.

  # Determine UUIDs of interfaces to add
  xe pif-list
  
  # Create new network (will return network UUID)
  xe network-create name-label=bond0
  
  # Create bonding (will return bonding UUID)
  xe bond-create network-uuid=<network UUID> pif-uuids=<first pif UID>,<second pif UID>[,...]
  
  # Set bonding flags for bond0
  xe pif-param-set uuid=<bond0 UUID> other-config:bond-mode=802.3ad
  xe pif-param-set uuid=<bond0 UUID> other-config:bond-mode=lacp
  
  # Once your switch is configured check bond0 with
  cat /proc/net/bonding/bond0
  
  # Also try
  ovs-appctl bond/show bond0
  

• XenServer - Restore VM from Image: Use “xe vm-import” to create a new VM with a new UUID:

  xe vm-import filename=image.xva preserve=true
  

• Xen Server - Ubuntu bug: read-only filesystem