John,
For vmware, you have 2 options, clock sync will work with native NTP daemon
using local ntp servers in your datacenter or use vmware tools native time
keeping technique.
We have over 2500 VMs, and while we have vmware tools installed on all vms, we
choose to use native linux NTPD for time sync VS vmware hypervisor provided
time sync. In past, vmware tools time sync was buggy and not recommended, so we
decided to keep it simple and make use of existing ntp servers. As of now,
inherent issues maybe, if you go through major upgrade of Vsphere, if you
change vmware hardware version, if you don't update the tools - you have 3
places where time keeping may break (though I hope vmware dev team consider all
that - it is still a possibility)
I propose we make this optional when cluster is configured.
For example, we have a check box that says
1) use local NTP servers for time keeping (if selected)
NTP SERVER1
NTP SERVER2
2) use native hypervisor vm tools for time sync (be it vmware,kvm, xen or
whatever else it may be)
We let user make his own decision on how to go about this issue, and user would
know best what's applicable for his environment VS us, making decisions on
their behalf.
For vmware, we have have to submit 3 more arguments into "vm.details" attribute
with an option for timesync=vmtools ot timesync=ntp
If timesync=ntp, get values of ntpserver1 and ntpserver2, configure
local ntp.conf file to use with native linux ntpd daemon
If timesync=tools, use vm tools provided time keeping technique
Feedback is welcome,
Thanks
-ilya
> -----Original Message-----
> From: John Burwell [mailto:jburw...@basho.com]
> Sent: Thursday, May 30, 2013 1:44 PM
> To: dev@cloudstack.apache.org
> Subject: Re: [DISCUSS] How to best do time sync. (WAS: [VOTE] Release
> Apache CloudStack 4.1.0 (fifth round))
>
> IIya,
>
> I can't speak to KVM, but on VMWare, clock sync won't work without tools.
> It's not an option.
>
> Thanks,
> -John
>
>
> On Thu, May 30, 2013 at 1:30 PM, Musayev, Ilya <imusa...@webmd.net>
> wrote:
>
> > I'd say Cluster setting.
> >
> > We should let users pick if they want to use hypervisor tools based
> > sync or local/external NTP servers.
> >
> > I'm all for local/external NTP servers, as I know how those never gave
> > me issues in past (especially when you go through hypervisors upgrades
> > and vm tools upgrades).
> >
> >
> >
> > > -----Original Message-----
> > > From: John Burwell [mailto:jburw...@basho.com]
> > > Sent: Thursday, May 30, 2013 1:02 PM
> > > To: dev@cloudstack.apache.org
> > > Subject: Re: [DISCUSS] How to best do time sync. (WAS: [VOTE]
> > > Release Apache CloudStack 4.1.0 (fifth round))
> > >
> > > Ilya,
> > >
> > > One very important note is that NTP is only used for Xen. For KVM
> > > and VMWare, time sync is accomplished through kernel drivers/system
> > > daemons with NTP configured in the hypervisor configuration.
> > > Therefore, this
> > model
> > > would need to be conditional based on the hypervisor type --
> > > possibly a cluster-level setting?
> > >
> > > Thanks,
> > > -John
> > >
> > > On May 30, 2013, at 12:58 PM, "Musayev, Ilya" <imusa...@webmd.net>
> > > wrote:
> > >
> > > > Thanks Chip.
> > > >
> > > > I've posted this response under CLOUDSTACK-2492.. curious what
> > > > others
> > > may think about a long term solution to this problem..
> > > >
> > > > --------------
> > > > I think we should make the whole NTP schema more modular and
> robust.
> > > >
> > > > For example, in my experience working for several companies, not
> > > > even once have we used vmware tools time sync - due to known bugs
> > > > and issues. Instead we would prefer to use local NTP server or
> > > > external pool.ntp.org
> > > >
> > > > There are two way we can address this:
> > > >
> > > > Quick solution (quick means not ideal):
> > > > Capture the NTP servers defined on MS and feed it as arguments to
> > > > system vms On initial start of the system vm, check if you can
> > > > access ntp servers defined on MS vm, if not, check if you can
> > > > access pool.ntp.org servers - if none defined - use hypervisor
> > > > tools sync
> > > >
> > > > Long term solution:
> > > > When adding zones, define NTP servers in UI to be used with system
> > > > VMs
> > > or bypass NTP servers and allow vm-tools time sync with hypervisor.
> > > >
> > > > Thoughts?
> > > >
> > > > Thanks
> > > > ilya
> > > >
> > > >> -----Original Message-----
> > > >> From: Chip Childers [mailto:chip.child...@sungard.com]
> > > >> Sent: Wednesday, May 29, 2013 2:30 PM
> > > >> To: dev@cloudstack.apache.org
> > > >> Subject: [DISCUSS] How to best do time sync. (WAS: [VOTE] Release
> > > >> Apache CloudStack 4.1.0 (fifth round))
> > > >>
> > > >> Ilya,
> > > >>
> > > >> I'm breaking off a new thread for this discussion. If you want
> > > >> to discuss the design options presented in the jira, this would
> > > >> be a good thread for that. ;-)
> > > >>
> > > >> -chip
> > > >>
> > > >> On Wed, May 29, 2013 at 06:24:27PM +0000, Musayev, Ilya wrote:
> > > >>> John,
> > > >>>
> > > >>> I clearly see your concern, please review my response under
> > > >>> CLOUDSTACK-
> > > >> 2492.
> > > >>>
> > > >>> Thanks
> > > >>> ilya
> > > >>>
> > > >>>> -----Original Message-----
> > > >>>> From: John Burwell [mailto:jburw...@basho.com]
> > > >>>> Sent: Wednesday, May 29, 2013 10:10 AM
> > > >>>> To: dev@cloudstack.apache.org
> > > >>>> Subject: Re: [VOTE] Release Apache CloudStack 4.1.0 (fifth
> > > >>>> round)
> > > >>>>
> > > >>>> -0. I don't believe we should be shipping a release with known
> > > >>>> clock sync issues (see CLOUDSTACK-
> > > >>>> 2492<https://issues.apache.org/jira/browse/CLOUDSTACK-2492>).
> > > >>>> Since the community voted to go forward, I will not cast a -1.
> > > >>>> However, I feel it is important to highlight operational issues
> > > >>>> that, in my view, a system such as CloudStack should never
> > > >>>> knowingly
> > > >> ship.
> > > >>>>
> > > >>>> -John
> > > >
> > > >
> > >
> >
> >
> >
