Who Should Install This Hotfix?

This is a hotfix for customers running Citrix Hypervisor 8.2.

Information About this Hotfix

Improvements in this hotfix

To improve security, weaker ciphersuites have been removed from the list of ciphersuites that are supported for SSH communication. Only the following ciphersuites are now supported:

Ciphers:

• aes128-cbc
• aes192-cbc
• aes256-cbc
• aes128-ctr
• aes192-ctr
• aes256-ctr
• aes128-gcm@openssh.com
• aes256-gcm@openssh.com
• chacha20-poly1305@openssh.com

MACs:

• hmac-sha1
• hmac-sha2-256
• hmac-sha2-512
• hmac-sha1-etm@openssh.com
• hmac-sha2-256-etm@openssh.com
• hmac-sha2-512-etm@openssh.com

Key Exchange algorithms:

• diffie-hellman-group14-sha1
• diffie-hellman-group-exchange-sha256
• ecdh-sha2-nistp256
• ecdh-sha2-nistp384
• ecdh-sha2-nistp521
• curve25519-sha256
• curve25519-sha256@libssh.org

Host Key algorithms:

• ecdsa-sha2-nistp256-cert-v01@openssh.com
• ecdsa-sha2-nistp384-cert-v01@openssh.com
• ecdsa-sha2-nistp521-cert-v01@openssh.com
• ssh-ed25519-cert-v01@openssh.com
• ssh-rsa-cert-v01@openssh.com
• ecdsa-sha2-nistp256
• ecdsa-sha2-nistp384
• ecdsa-sha2-nistp521
• ssh-ed25519,ssh-rsa

To benefit from the improvement to ciphersuite security, you must restart your servers. However, a restart is not required to benefit from the other fixes included in this hotfix.

Issues resolved in this hotfix

This hotfix resolves the following issues:

• On slower systems, xen-bugtool can experience time outs.
• A misconfigured PCI interface-rename rule leaves all host interfaces inaccessible.
• If there is an issue in your NTP environment, sometimes on Citrix Hypervisor start up it can take up to 10 minutes to reach the xsconsole.

  The wait time has been reduce to 2 minutes. You are also advised to investigate your NTP set up and change any configuration that is incorrect.

Installing the Hotfix

Customers should use either XenCenter or the Citrix Hypervisor Command Line Interface (CLI) to apply this hotfix. When the installation is complete, see the Post-update tasks in the table Information About this Hotfix for information about any post-update tasks you should perform for the update to take effect. As with any software update, back up your data before applying this update. Citrix recommends updating all hosts within a pool sequentially. Upgrading of hosts should be scheduled to minimize the amount of time the pool runs in a "mixed state" where some hosts are upgraded and some are not. Running a mixed pool of updated and non-updated hosts for general operation is not supported.

Note: The attachment to this article is a zip file. It contains the hotfix update package only. Log in to your Citrix account and click the following link to download the source code for any modified open source components XS82E015-sources.iso. The source code is not necessary for hotfix installation: it is provided to fulfill licensing obligations. You must be logged in to access this link.

Installing the Hotfix by using XenCenter

Choose an Installation Mechanism

There are three mechanisms to install a hotfix:

1. Automated Updates
2. Download update from Citrix
3. Select update or Supplemental pack from disk

The Automated Updates feature is available for Citrix Hypervisor Premium Edition customers, or to those who have access to XenServer through their Citrix Virtual Apps and Desktops entitlement. For information about installing a hotfix using the Automated Updates feature, see the Applying Automated Updates in the Citrix Hypervisor documentation.

For information about installing a hotfix using the Download update from Citrix option, see Applying an Update to a Pool in the Citrix Hypervisor documentation.

The following section contains instructions on option (3) installing a hotfix that you have downloaded to disk:

Follow the on-screen recommendations to resolve any update prechecks that have failed. If you want XenCenter to automatically resolve all failed prechecks, click Resolve All. When the prechecks have been resolved, click Next.

Note: If you click Cancel at this stage, the Install Update wizard reverts the changes and removes the update file from the host.

1. Download the hotfix to a known location on a computer that has XenCenter installed.
2. Unzip the hotfix zip file and extract the .iso file
3. In XenCenter, on the Tools menu, select Install Update. This displays the Install Update wizard.
4. Read the information displayed on the Before You Start page and click Next to start the wizard.
5. Click Browse to locate the iso file, select XS82E015.iso and then click Open.
6. Click Next.
7. Select the pool or hosts you wish to apply the hotfix to, and then click Next.
8. The Install Update wizard performs a number of update prechecks, including the space available on the hosts, to ensure that the pool is in a valid configuration state. The wizard also checks whether the hosts need to be rebooted after the update is applied and displays the result.
9. Choose the Update Mode. Review the information displayed on the screen and select an appropriate mode.
10. Click Install update to proceed with the installation. The Install Update wizard shows the progress of the update, displaying the major operations that XenCenter performs while updating each host in the pool.
11. When the update is applied, click Finish to close the wizard.
12. If you chose to carry out the post-update tasks, do so now.

Installing the Hotfix by using the xe Command Line Interface

1. Download the hotfix file to a known location.
2. Extract the .iso file from the zip.
3. Upload the .iso file to the Pool Master by entering the following commands:
   (Where -s is the Pool Master's IP address or DNS name.)

   xe -s <server> -u <username> -pw <password> update-upload file-name=<filename>\XS82E015.iso

   Citrix Hypervisor assigns the update file a UUID which this command prints. Note the UUID.

   4391282a-37d6-4ff6-8417-935a5bdd397d

4. Apply the update to all hosts in the pool, specifying the UUID of the update:

   xe update-pool-apply uuid=4391282a-37d6-4ff6-8417-935a5bdd397d

   Alternatively, if you need to update and restart hosts in a rolling manner, you can apply the update file to an individual host by running the following:

   xe update-apply host=<host> uuid=4391282a-37d6-4ff6-8417-935a5bdd397d

    

5. Verify that the update was applied by using the update-list command.

   xe update-list -s <server> -u root -pw <password> name-label=XS82E015

   If the update is successful, the hosts field contains the UUIDs of the hosts to which this update was successfully applied. This should be a complete list of all hosts in the pool.
6. Use the update-pool-clean command to remove the update files from all hosts in the pool. This command frees up space on shared storage and does not uninstall the update.

   xe update-pool-clean uuid=4391282a-37d6-4ff6-8417-935a5bdd397d

Files

Hotfix File

Files Updated

For more information, see Citrix Hypervisor Documentation.

If you experience any difficulties, contact Citrix Technical Support.