====== Xen-tools ======

= Setting up Trainee Admin Xen VMs Automatically =

This how-to guide covers streamlining the setting up of Xen VMs using xen-tools. 
The setting up of Xen and VMs is also discussed here: [[:Admin/SetupGuides/SettingUpXenVMs]]

====== In brief, to Create a VM ======
 ssh dom0
 xen-create-image --hostname dom0-vm## --ip 192.168.0.15

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Documented Procedure on getting to the above stage:

====== 1. Install Xen ======
 apt-get install linux-image-2.6-xen-686 xen-hypervisor-3.0.3-1-i386-pae xen-tools bridge-utils libc6-xen sysfsutils

====== 2. Setup Xen to use Bridge Networking ======
 vi /etc/xen/xend-config.sxp
 (vif-script vif-bridge)
 (network-script network-bridge)

====== 3. Reboot dom0 and Check Xen ======
 xm list
 #shows machines running
 
 ifconfig
 #you should see entries for: peth0 and xenbr0

====== 4. Configure Xen-tools ======
This step shows all the settings which were required:
 vi /etc/xen-tools/xen-tools.conf
 #uncommented lines are as follows:
 lvm = hexvg
 debootstrap = 1
 size   = 4Gb      # Disk image size.
 memory = 64Mb    # Memory size
 swap   = 128Mb    # Swap size
 # noswap = 1      # Don't use swap at all for the new system.
 fs     = ext3     # use the EXT3 filesystem for the disk image.
 dist   = etch    # Default distribution to install.
 image  = sparse   # Specify sparse vs. full disk images.
 gateway   = 192.168.0.1
 netmask   = 255.255.255.0
 passwd = 1
 kernel = /boot/vmlinuz-2.6.18-4-xen-686
 initrd = /boot/initrd.img-2.6.18-4-xen-686
 mirror = http://ftp.ie.debian.org/debian/

Configure /etc/profile to use a proxy on dom0:
 vi /etc/profile
 export http_proxy="http://proxy:3128"
 #case sensitive for debootstrap!!

Copy files for domU skeleton as follows:
 mkdir -p /etc/xen-tools/skel/root/.ssh/
 mkdir -p /etc/xen-tools/skel/etc/
 
 cp /root/.ssh/authorized_keys2 /etc/xen-tools/skel/root/.ssh/
 cp /etc/profile /etc/xen-tools/skel/etc/

====== 5. Manage xen-tools ======
Xen-tools is a front end, doing a lot of things:
  * xen-tools will handle creating and deleting lvm partitions for vms. 
  * xen-tools will mount and copy across network setting and whatever files you wish onto the domU.
  * xen-tools will mount and debootstrap the os you specified onto the domU.

Note, the settings which are not specified on the command line are kept in: /etc/xen-tools/xen-tools.conf
 xen-create-image --hostname hex-vm04 --ip 192.168.0.15

 xen-delete-image hex-vm04
 #cleanly delets the vm, including removing the lvm partition!

 xen-list-images

Xen Specific Tools:
 xm create /etc/xen/hex-vm04.cfg
 #VMs still need to be started manually.
 
 xm console hex-vm04
 #serial console in. Hit CTRL + } to escape
 
 xm shutdown hex-vm04
 #brings down the VM

====== Conclusion ======
  * xen-tools greatly speeds up creating the VMs. Note: it does take xen-tools between 10-15 minutes to create and debootstrap a VM, so be patient.
  * As long as VMs are running when dom0 goes down, xen-tools will bring back up all domU's on restart.
  * Use "xm list" and "xm top" to see an exact list of whats running.
  * With a later version of xen-tools (later than what is with etch), it is possible to setup incremental IPs, so the IP does not have to be specified when going xen-create-image.
  * cp /root/.ssh/authorized_keys2 /etc/xen-tools/skel/root/.ssh/ allows you to ssh into the new VM without a password.
  * If you dont have "passwd = 1" then all existing users and passwords from existing dom0 will be copied across to domU.
  * Minor problems occurred from xen-tools. On creating a new VM, it added an entry into /etc/hosts on dom0. As I was testing with a few setups, old ips remained within /etc/hosts. The dns names are now added into dns, so they dont need to be in the hosts file.
  * When the domU is up and running, you might want to run:
 apt-get remove locales
 apt-get install locales
 dpkg-reconfigure locales
 tzconfig