[ntp:questions] Re: Running ntpd on user-mode Linux?

CBee I.Dont at want.your.spam
Thu Sep 30 13:00:13 UTC 2004

Tapio Sokura wrote:

> Hi,
> Has anyone run ntpd inside a user-mode Linux or on any other "client" 
> operating system that runs inside another OS? Does it work? Is the time 
> on the host OS and all its client OSes always the same? So if I want to 
> have accurate time in the client OS, is the only option to have the host 
> OS run ntpd or some other time synchronization mechanisms? With host I 
> mean the OS on the bottom that talks to the hardware and manages the 
> client OSes that run on top of the host OS.
> I would have tried running ntpd inside user-mode Linux myself, but I 
> don't have a spare computer to try this on at the moment.
>   Tapio

If the guest-os gets its time from the host-os then ntp is only needed at the host.

With user-mode linux I guess (no experience) that the time is obtained from the 
host-os and gets direct into the guest os. Hence if the host is in sync, the 
guest is too.

With VMWare I know there is (was in previous versions) a setting in the guest to 
follow the time of the host or not. This only hooks the guests bios-time to the 
hosts-os time. With M$Windows guests this is perfect: have the host sync with 
the ntp server and all is in sync. With linux in the guest, it must sync the 
guests-linux-time with the guests-bios-time where ntp can do its job (clock or such).

Hence it depends how the time travels from the host-os to the guest-os. In the 
end, ntp can suit some needs.


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