Xen troubleshooting

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Revision as of 08:10, 22 January 2019 by Saurabh (talk | contribs)

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Xen troubleshooting

Delayed starting of xend service on PC start-up

During normal PC boot service xend may take very long time to start or completely fail to start. This can happen if instead of eth0 we have eth1 or eth2 as default network interface. To solve this problem we should make the interface with name eth0 default network interface. We can do this by either changing physical connections or by renaming interfaces using configuration files. Once eth0 is the enabled by default on boot and is working when we try to start xend service then we do not face any delay problems.


Installing windows Guest over bootable virtual harddisk

When we try to install Windows XP over bootable virtual harddisk using xen command line, then we usually are not able to start vncviewer fast enough to use the "press any key to boot from cd option...." provided by Windows XP installation CD. Hence this causes problem when we try to install Windows XP on virtual hdd which already has a bootable OS.

To get around this problem we can create xen domainU guest using

  1. First use 'xm create <filename> -p' to create guest, so that guest gets created in paused state
  2. Then connect to guest using vncviewer.
  3. Then unpause the guest using 'xm unpause <id>'

This would allow one to quickly select option of booting from CD when prompted.


Steps to solve interface MAC stuck to FE:FF:FF:FF:FF:FF problem with xen

Sometimes due to bad shutdown or renaming of interfaces interface MAC stucks to FE:FF:FF:FF:FF:FF and nothing works properly. Also this MAC comes automatically even after reboot. To solve this problem following steps can be used:

  1. Use 'shutdown -h now' command to shutdown machine.
  2. Remove power cable from back of CPU for about 10-15 seconds. This is important to remove power from NIC card.
  3. Boot machine and login as root.
  4. Verify eth0 is down, but has proper MAC address.
  5. Go to '/etc/sysconfig/network-scripts' directory. Rename 'ifcfg-eth0.bak' to 'ifcfg-eth0 if it gets created due to above steps'. It is important to verify that ifcfg-eth0 has correct value for HWADDR.
  6. Use 'service network restart' and verify eth0 is up and with proper MAC.
  7. Reboot machine and now interface MAC getting stuck to FE:FF:FF:FF:FF:FF problem should not occur.



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