Passing a limited amount of disk devices to jails

[Willem Jan Withagen]

On 9-6-2017 16:20, Miroslav Lachman wrote:
> Willem Jan Withagen wrote on 2017/06/09 15:48:
>> On 9-6-2017 11:23, Steven Hartland wrote:
>>> You could do effectively this by using dedicated zfs filesystems per
>>> jail
>>
>> Hi Steven,
>>
>> That is how I'm going to do it, when nothing else works.
>> But then I don't get to test the part of building the ceph-cluster from
>> raw disk...
>>
>> I was more thinking along the lines of tinkering with the devd.conf or
>> something. And would appreciate opinions on how to (not) do it.
> 
> I totally skipped devd.conf in my mind in previous reply. So maybe you
> can really use devd.conf to allow access to /dev/adaX devices or you can
> use ZFS zvol if you have big pool and need some smaller devices to test
> with.

I want the jail to look as much as a normal system would, and then run
ceph-tools on them. And they would like to see /dev/{disk}....

Now I have found /sbin/devfs which allows to add/remove devices to an
already existing devfs-mount.

So I can 'rule add type disk unhide' and see the disks.
Gpart can then list partitions.
But any of the other commands is met with an unwilling system:

root at ceph-1:/ # gpart delete -i 1 ada0
gpart: No such file or directory

So there is still some protection in place in the jail....

However dd-ing to the device does overwrite some stuff.
Since after the 'dd if=/dev/zero of=/dev/ada0' gpart reports a corrupt
gpartition.

But I don't see any sysctl options to toggle that on or off

--WjW