[Samba] Samba on Debian 8: ADS domain questions

[mathias dufresne]

2016-12-14 18:42 GMT+01:00 Stefan G. Weichinger via samba <
samba at lists.samba.org>:

> Am 2016-12-14 um 14:55 schrieb L.P.H. van Belle via samba:
>
>> You miss read mathias ;-)
>
>

>
>>
>> This can be solved very easily booting VMs in the right order and
>>> possibly adding latency between VMs launches.
>>>
>>
>> The Guest DC is on fysical server where the member is also.
>>
>>
>>
>> How are you going to boot the GUEST os before the HOST os, on the same
>> server.
>>
>> This cant be done..
>>
>>
>>
>> Or did i miss read the question..
>>
>
> No, you understood correctly.
> It would maybe be solvable by delaying the start of the member server (on
> the HOST) after the DC is up ... but that seems too uncertain to me.
>
> I tend to:
>
> physical backup server (debian) runs samba AD DC
>
> physical file server (gentoo) runs samba member server
>
> No virtualization involved.
>
> *maybe* add a second DC in a VM later (?)
>
> DCs don't need others DCs to be up and running when starting.
Samba as file server, when member, won't work if no DC is available, but
anyway Samba should start.

So you don't necessarily need to delay start of these systems.



Depending on the amount of memory on the physical machines you should be
able to transform them as hypervisor only. Then you could move all services
into VMs.
As applications should consume almost same amount of memory when running on
VM than on physical, the amount of additional memory consumption in that
case would come from:
- VMs systems (which is generally very few when no application are running)
- disk caching/buffering (perhaps that could be lowered using LVM instead
of files for virtual disks, but I never really made tests to confirm that)

At home I use for almost a decade "1 VM = 1 service". Now I do also at
work. This way I have lot VM which increase complexity but doing that all
these systems are very simple (just the system + 1 service) so they are
very easy to manage, to repair and especially to rebuild when some issue
happens.
Same concept for the hypervisor, it is just running qemu and libvirtd.

I use Gentoo (at home, not at work where I have to use the kind of system
the client is attached to) for hypervisor. As there is only qemu/libvirtd,
as they don't rely on any service from VMs (except DNS and internet access)
this Gentoo has very packages installed (not much dependencies) and is also
easy to rebuild.

And with two physical machines you can achieve high availability too
spreading VM across both platforms, making every service running on both
physical hosts.