Re: [ovirt-users] Time synchronization in guest OS for Hosted Engine VM (for Kerberos)
On Tue, 27 Sep 2016 13:22:29 -0400 (EDT) Michal wrote: MS> > On 27 Sep 2016, at 19:12, aleksey.maksi...@it-kb.ru wrote: MS> > MS> > I'm afraid that in the future OS time may get out of sync because of kvm-clock MS> > And as a result Kerberos may stop working MS> > I hope I explained clearly MS> MS> Sorry, not really. You said you set up ntpd/chrony correctly. So how can the time get out of sync? Why do you think it can be because of kvmclock anyway? Do you refer to some specific bug? I'd guess that it's a misunderstanding of what kvmclock is. Someone guessing based on the name might think that it keeps the vm time in sync with the host. Which might lead one to think it would conflict with ntp (two different things trying to manage time). If you know that kvmclock is essentially just a way to monitor the passage of time (tick-tock-tick-tock) using the host's timer, then it makes sense that you need also need ntp to tweak the current time to adjust for the minor drift inherit in any clock. Robert -- Senior Software Engineer @ Parsons pgpFr50IROpBx.pgp Description: OpenPGP digital signature ___ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
Re: [ovirt-users] Time synchronization in guest OS for Hosted Engine VM (for Kerberos)
Robert, you're right. Thanks for clarifying. 28.09.2016, 15:10, "Robert Story" : > On Tue, 27 Sep 2016 13:22:29 -0400 (EDT) Michal wrote: > MS> > On 27 Sep 2016, at 19:12, aleksey.maksi...@it-kb.ru wrote: > MS> > > MS> > I'm afraid that in the future OS time may get out of sync because of > kvm-clock > MS> > And as a result Kerberos may stop working > MS> > I hope I explained clearly > MS> > MS> Sorry, not really. You said you set up ntpd/chrony correctly. So how can > the time get out of sync? Why do you think it can be because of kvmclock > anyway? Do you refer to some specific bug? > > I'd guess that it's a misunderstanding of what kvmclock is. Someone > guessing based on the name might think that it keeps the vm time in sync > with the host. Which might lead one to think it would conflict with ntp > (two different things trying to manage time). > > If you know that kvmclock is essentially just a way to monitor the passage > of time (tick-tock-tick-tock) using the host's timer, then it makes sense > that you need also need ntp to tweak the current time to adjust for the > minor drift inherit in any clock. > > Robert > > -- > Senior Software Engineer @ Parsons ___ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
Re: [ovirt-users] Time synchronization in guest OS for Hosted Engine VM (for Kerberos)
Thank you 27.09.2016, 20:38, "Michal Skrivanek" : > kvmclock is the most accurate clock in Linux guests. Once you hit a bug we > can take a look at something, but until then I do not see a reason to modify > anything ___ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
Re: [ovirt-users] Time synchronization in guest OS for Hosted Engine VM (for Kerberos)
> On 27 Sep 2016, at 19:26, aleksey.maksi...@it-kb.ru wrote: > > No. At the moment I have no sync-time errors. I'm just asking hypothetically kvmclock is the most accurate clock in Linux guests. Once you hit a bug we can take a look at something, but until then I do not see a reason to modify anything > > 27.09.2016, 20:22, "Michal Skrivanek" : >>> On 27 Sep 2016, at 19:12, aleksey.maksi...@it-kb.ru wrote: >>> >>> I'm afraid that in the future OS time may get out of sync because of >>> kvm-clock >>> And as a result Kerberos may stop working >>> I hope I explained clearly >> >> Sorry, not really. You said you set up ntpd/chrony correctly. So how can the >> time get out of sync? Why do you think it can be because of kvmclock anyway? >> Do you refer to some specific bug? ___ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
Re: [ovirt-users] Time synchronization in guest OS for Hosted Engine VM (for Kerberos)
No. At the moment I have no sync-time errors. I'm just asking hypothetically 27.09.2016, 20:22, "Michal Skrivanek" : >> On 27 Sep 2016, at 19:12, aleksey.maksi...@it-kb.ru wrote: >> >> I'm afraid that in the future OS time may get out of sync because of >> kvm-clock >> And as a result Kerberos may stop working >> I hope I explained clearly > > Sorry, not really. You said you set up ntpd/chrony correctly. So how can the > time get out of sync? Why do you think it can be because of kvmclock anyway? > Do you refer to some specific bug? ___ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
Re: [ovirt-users] Time synchronization in guest OS for Hosted Engine VM (for Kerberos)
> On 27 Sep 2016, at 19:12, aleksey.maksi...@it-kb.ru wrote: > > I'm afraid that in the future OS time may get out of sync because of kvm-clock > And as a result Kerberos may stop working > I hope I explained clearly Sorry, not really. You said you set up ntpd/chrony correctly. So how can the time get out of sync? Why do you think it can be because of kvmclock anyway? Do you refer to some specific bug? > > 27.09.2016, 19:59, "Michal Skrivanek" : >>> On 27 Sep 2016, at 18:57, aleksey.maksi...@it-kb.ru wrote: >>> >>> Michal, please, read my first message. >>> I have 3 times wrote that the NTP client works for me. >>> The question is not that. >>> The question is how to disable kvm-clock for a virtual machine? >> >> What leads you to think you have to do that? Why? ___ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
Re: [ovirt-users] Time synchronization in guest OS for Hosted Engine VM (for Kerberos)
I'm afraid that in the future OS time may get out of sync because of kvm-clock And as a result Kerberos may stop working I hope I explained clearly 27.09.2016, 19:59, "Michal Skrivanek" : >> On 27 Sep 2016, at 18:57, aleksey.maksi...@it-kb.ru wrote: >> >> Michal, please, read my first message. >> I have 3 times wrote that the NTP client works for me. >> The question is not that. >> The question is how to disable kvm-clock for a virtual machine? > > What leads you to think you have to do that? Why? ___ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
Re: [ovirt-users] Time synchronization in guest OS for Hosted Engine VM (for Kerberos)
> On 27 Sep 2016, at 18:57, aleksey.maksi...@it-kb.ru wrote: > > Michal, please, read my first message. > I have 3 times wrote that the NTP client works for me. > The question is not that. > The question is how to disable kvm-clock for a virtual machine? What leads you to think you have to do that? Why? > Do I have to do it at all? If you want, how to do it correctly? > > My hypervisors OS - CentOS 7.2 Thanks > > > 27.09.2016, 19:39, "Michal Skrivanek" : >>> On 27 Sep 2016, at 17:57, aleksey.maksi...@it-kb.ru wrote: >>> >>> Yaniv, I do not understand how to do it. >>> You can tell steps how to do it? >>> >>> 27.09.2016, 18:53, "Yaniv Dary" : You can do that from the edit VM dialog. >> >> I don't think you can >> >> Aleksey, >> I don't understand what issue you have. Time is getting desynchronized? How >> did you configure your ntp client? Does it behave the same on different >> hypervisor? What is the hypervisor OS? >> >> Thanks, >> michal >> >>> ___ >>> Users mailing list >>> Users@ovirt.org >>> http://lists.ovirt.org/mailman/listinfo/users ___ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
Re: [ovirt-users] Time synchronization in guest OS for Hosted Engine VM (for Kerberos)
Michal, please, read my first message. I have 3 times wrote that the NTP client works for me. The question is not that. The question is how to disable kvm-clock for a virtual machine? Do I have to do it at all? If you want, how to do it correctly? My hypervisors OS - CentOS 7.2 27.09.2016, 19:39, "Michal Skrivanek" : >> On 27 Sep 2016, at 17:57, aleksey.maksi...@it-kb.ru wrote: >> >> Yaniv, I do not understand how to do it. >> You can tell steps how to do it? >> >> 27.09.2016, 18:53, "Yaniv Dary" : >>> You can do that from the edit VM dialog. > > I don't think you can > > Aleksey, > I don't understand what issue you have. Time is getting desynchronized? How > did you configure your ntp client? Does it behave the same on different > hypervisor? What is the hypervisor OS? > > Thanks, > michal > >> ___ >> Users mailing list >> Users@ovirt.org >> http://lists.ovirt.org/mailman/listinfo/users ___ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
Re: [ovirt-users] Time synchronization in guest OS for Hosted Engine VM (for Kerberos)
> On 27 Sep 2016, at 17:57, aleksey.maksi...@it-kb.ru wrote: > > Yaniv, I do not understand how to do it. > You can tell steps how to do it? > > 27.09.2016, 18:53, "Yaniv Dary" : >> You can do that from the edit VM dialog. I don't think you can Aleksey, I don't understand what issue you have. Time is getting desynchronized? How did you configure your ntp client? Does it behave the same on different hypervisor? What is the hypervisor OS? Thanks, michal > ___ > Users mailing list > Users@ovirt.org > http://lists.ovirt.org/mailman/listinfo/users > > ___ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
Re: [ovirt-users] Time synchronization in guest OS for Hosted Engine VM (for Kerberos)
Yaniv, I do not understand how to do it. You can tell steps how to do it? 27.09.2016, 18:53, "Yaniv Dary" : > You can do that from the edit VM dialog. ___ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
Re: [ovirt-users] Time synchronization in guest OS for Hosted Engine VM (for Kerberos)
You can do that from the edit VM dialog. Yaniv Dary Technical Product Manager Red Hat Israel Ltd. 34 Jerusalem Road Building A, 4th floor Ra'anana, Israel 4350109 Tel : +972 (9) 7692306 8272306 Email: yd...@redhat.com IRC : ydary On Tue, Sep 27, 2016 at 6:31 PM, wrote: > I think that the NTP-client (chrony) in guest OS may conflict with the > kvm-clock (vm guest OS time sync from vm-host). > Do I need to turn off kvm-clock in virtual machine properties? > And how to do it? > > What is not clear in my question? > > 27.09.2016, 18:24, "aleksey.maksi...@it-kb.ru" >: > > I wrote that I had set up the NTP client. The question is not that.. > > > > 27.09.2016, 17:56, "Yaniv Dary" : > >> Why not use ntp? > ___ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
Re: [ovirt-users] Time synchronization in guest OS for Hosted Engine VM (for Kerberos)
I think that the NTP-client (chrony) in guest OS may conflict with the kvm-clock (vm guest OS time sync from vm-host). Do I need to turn off kvm-clock in virtual machine properties? And how to do it? What is not clear in my question? 27.09.2016, 18:24, "aleksey.maksi...@it-kb.ru" : > I wrote that I had set up the NTP client. The question is not that.. > > 27.09.2016, 17:56, "Yaniv Dary" : >> Why not use ntp? ___ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
Re: [ovirt-users] Time synchronization in guest OS for Hosted Engine VM (for Kerberos)
I wrote that I had set up the NTP client. The question is not that.. 27.09.2016, 17:56, "Yaniv Dary" : > Why not use ntp? ___ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
Re: [ovirt-users] Time synchronization in guest OS for Hosted Engine VM (for Kerberos)
Why not use ntp? Yaniv Dary Technical Product Manager Red Hat Israel Ltd. 34 Jerusalem Road Building A, 4th floor Ra'anana, Israel 4350109 Tel : +972 (9) 7692306 8272306 Email: yd...@redhat.com IRC : ydary On Tue, Sep 27, 2016 at 4:51 PM, wrote: > No ideas? > ___ > Users mailing list > Users@ovirt.org > http://lists.ovirt.org/mailman/listinfo/users > ___ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
Re: [ovirt-users] Time synchronization in guest OS for Hosted Engine VM (for Kerberos)
No ideas? ___ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
