Time synchronization for hosts running onVMWare - NTP
This is a discussion on Time synchronization for hosts running onVMWare - NTP ; I'm cross-posting this from the Kerberos mailing list since this is
useful information for people running O/S's on top of VMWare and people
come here for time issues.
Danny
-------- Original Message --------
>How about using the VMWare-Player for setting ...
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Time synchronization for hosts running onVMWare
I'm cross-posting this from the Kerberos mailing list since this is
useful information for people running O/S's on top of VMWare and people
come here for time issues.
Danny
-------- Original Message --------
>How about using the VMWare-Player for setting up various test machines?
>Ciao, Michael.
it's a good idea, but be careful with the time synchronization.
Some guest OS consistently run more slowly or more quickly than real
world time. The reason that caused the slowing time inside guest system
is because of that the guest clock frequency is setting too high than
the host OS can offer.
And if you have a time problem Kerberos can't work properly, specially
the ticket manager.
If yours guest OS is Linux you have a workaround on the vmware's web
site :
http://kb.vmware.com/selfservice/vie...n_US&externalI
d=1420
if you want use FreeBSD check this link , but it's in French sorry,
maybe it can help :
http://casys.crevetor.org/index.php/...e-server_Guest
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Thomas Boutry
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Re: Time synchronization for hosts running onVMWare
I added this section to the NTP Wiki a few weeks ago to address
similar questions:
http://support.ntp.org/bin/view/Support/VMWareNTP
We are wrapping up a large virtualization project at my office, and I
was surprised how poorly virtual machines keep time. Note that this
issue is not specific to VMware - all virtualization solutions have
the same problem with time itself being virtualized (Xen, Microsoft
Hyper-V, KVM, etc...)
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RPM
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Re: Time synchronization for hosts running on VMWare
On Jul 14, 11:29*am, malay...@gmail.com (Ryan Malayter) wrote:
> issue is not specific to VMware - all virtualization solutions have
> the same problem with time itself being virtualized (Xen, Microsoft
> Hyper-V, KVM, etc...)
That doesn't seem right. Some forms of virtualization virtualize the
time in this manner, but some do not. For instance on a multiple
processor system, any type 1 hypervisor like xen or Hyper-X should be
able to keep the time just fine. With other types like VMware and
Virtualbox that share the resources between the host OS and the
virtual one, it only stands to reason that the time keeping will be
shaky at best.
Brian Utterback
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Re: Time synchronization for hosts running onVMWare
On Sun, Jul 20, 2008 at 12:18 PM, wrote:
> That doesn't seem right. Some forms of virtualization virtualize the
> time in this manner, but some do not. For instance on a multiple
> processor system, any type 1 hypervisor like xen or Hyper-X should be
> able to keep the time just fine. With other types like VMware and
> Virtualbox that share the resources between the host OS and the
> virtual one, it only stands to reason that the time keeping will be
> shaky at best.
It seems Xen has the same issues as VMware... see:
http://xen.org/files/summit_3/Xen_HVM_SMP.pdf
Interrupts (including timer interrupts) are delayed, and/or batched
with all x86 virtualization platforms of which I'm aware.
--
RPM
