Citrix XenServer multiple security updates

Today (November 13th 2012) Citrix has released a critical update for all of it’s XenServer products.

A number of security vulnerabilities have been identified in Citrix XenServer. These vulnerabilities affect all currently supported versions of Citrix XenServer up to and including version 6.1.

The following denial of service vulnerabilities have been addressed:

  • Timer overflow DoS vulnerability (CVE-2012-4535)
  • pirq range check DoS vulnerability (CVE-2012-4536)
  • Memory mapping failure DoS vulnerability (CVE-2012-4537)
  • Unhooking empty PAE entries DoS vulnerability (CVE-2012-4538)
  • Grant table hypercall infinite loop DoS vulnerability (CVE-2012-4539)
  • XENMEM_add_to_physmap DoS vulnerability (CVE-2012-4557) Continue reading “Citrix XenServer multiple security updates”

Hotfix XS60E021 for XenServer 6.0

Besides Hotfix 13 for XenServer 6.0.2 Citrix has released hotfix 21 for XenServer 6.0.

This hotfix resolves the following issues:

  1. Constant transmission of low data rate Ethernet traffic through the netback interface can saturate a control domain (dom0) CPU.
  2. Attempts to attach a Storage Repository (SR) that contains a large number of Virtual Disk Images (VDIs), to a pool member, can fail.
  3. Creating a NIC bond in a Linux bridge environment, using a NIC that has VLANs configured on it, can result in loss of network connectivity.
  4. Restarting XAPI in a pool consisting of a large number of VDIs can cause pool members to indefinitely enter maintenance mode. Continue reading “Hotfix XS60E021 for XenServer 6.0”

New hotfix XS60E017 for XenServer 6.0

Issues Resolved In This Hotfix

This hotfix resolves the following issues:

  1. When creating a Storage Repository (SR) or a Virtual Disk (VDI), predefined XML entities (for example &, <, >, “, ‘) entered into the Name and Description fields, are written directly into the SR metadata. Any subsequent actions such as creating an SR or a VDI will fail with an error message, as the XML parser fails to parse metadata if it contains predefined XML entities.
  2. If there is a failure or a change in the number of paths to storage, attempts to create or destroy a VDI on an LVM-based SR may fail and will display the following error message: Error in Metadata Volume Operation on SR. The VDI will be created, but will lack a Name or Description.
  3. If multipath is active, on some storage arrays an error may occur when reading the Metadata Volume during an SR attach and display the following error message: Error in Metadata Volume Operation on SR.
  4. Storage may take several minutes to become available when using Dell PowerVault MD32xxi Storage Arrays with LVMoiSCSI
  5. Xapi frequently hangs pool slaves due to exceeding the number of sessions on the Pool Master.
  6. An SR may fail to connect when the XenServer host is booted with one failed iSCSI path when using Hitachi or Compellent storage arrays.
  7. XenServer may not discover all of the available LUNS when using the wildcard IQN. This occurs when using Compellent storage arrays via iSCSI.
  8. Improvements to the XenCenter Update functionality; customers are correctly notified in XenCenter when new XenServer Tools are available.

In addition, this hotfix includes the following previously released hotfixes.

NOTE: Customers MUST install Hotfix XS60E001 – For XenServer 6.0 before attempting to apply this hotfix. Continue reading “New hotfix XS60E017 for XenServer 6.0”

How to setup XenServer 6.x to auto-start Virtual Machines

In XenServer 6, the direct GUI ability to auto-start a Virtual Machine on the startup of XenServer was removed. This article describes how to set Virtual Machines to auto-start.


  • XenServer 6.0
  • XenServer 6.0.2


In XenServer 6, the auto-start functionality was removed because it interfered with High Availability (HA) and produced unexpected results during HA functions.

Procedure Continue reading “How to setup XenServer 6.x to auto-start Virtual Machines”