Recommendations for template virtual machines

Template virtual machines are used to create new virtual machines quickly. These should be installed carefully, as modifications in the templates will be in all of the VMs created from those. Here are listed some general and OS specific guidelines for creating the templates. These are here as pointers, you may disagree with some and use some other settings.

General guidelines

1. Give some consideration to your template disk size. Larger means less hassle in the future, but potentially more wasted space.
2. Do not give the template much RAM or more than one vCPU. Add those the the new machiens after creating them from the template.
3. Install VMware Tools
4. Install OS patches
5. Enable time synchronization with the host and disable guest time synchronization
6. Remove information specific to guest instance
7. Remove graphically intensive screen savers, "blank" is best
8. Optimize GUI for performance, not fancy effects.

Windows template suggestions

1. If you decide to disable Windows time synchronization, do it by setting the registry value "Type" in HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Parameters to "NoSync" (REG_SZ)
2. Defragment the disk once you are done installing everything.
3. Increase SCSI timeout by editing registry value "TimeOut" in  HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Disk to 60 (decimal). The value is in seconds. This lessens the chance of getting SCSI errors in case of path failover taking place due to an error.
4. Do not set an admin password. The customization tools cannot change it if one has been already set.

Linux template suggestions

1. Reset hostname to something generic (duh!)
2. Reset (delete) host SSH keys
3. REReset any MAC-address bound network configurations (on RHEL based, check /etc/sysconfig/network-scripts, on Debian based, check http://vmfaq.com/entry/24/ ).
4. Set time synchronization with the host by setting tools.syncTime=true in the vmx.
5. For server systems, disable graphical UI. Linux is administered from the console . (On RHEL based, set the default runlevel to 2 or 3 instead of 5 in /etc/inittab, on the line "id:5:initdefault:").
6. Optimize kernel options (check http://vmfaq.com/entry/18/ and the guest part of http://vmfaq.com/?View=entry&EntryID=25