ZFS and Jail :: nullfs mount :: nothing visible from host

[SK]

On 08/12/2016 16:14, Miroslav Lachman wrote:
> SK wrote on 2016/12/08 15:22:
>
>> So far I have tried to follow as many google results as possible using
>> jail, zfs, mountpoint, nullfs, manage zfs and so on. There were a few
>> sites coming up again and again but they were talking about ezjail (not
>> that I have anything against it, but I would prefer to be able to use
>> the base system as it is -- might help me learn a few things that ezjail
>> will hide from me :D)
>
> If you want to manage ZFS dataset from withing a jail, then you need 
> to use zfs set jailed=on property (see man zfs). But this data set 
> cannot be mounted as nullfs, it should be dedicated to the jail.
>
> You don't need ezjail because ezjail cannot do anything more than you 
> can do. It is just a shell script wrapper.
>
> Miroslav Lachman
>
Hi Miroslav

Thank you for your response. I tried setting it up like that (use zfs 
set jailed=on), and that did not work. I could not even run zfs from 
within the jail. Maybe I did something wrong -- so I am setting up a 
test box where I can try them all out.

I also came across these links
https://clinta.github.io/freebsd-jails-the-hard-way/
http://aaron.baugher.biz/unix/freebsd-jails-zfs-1

I will give these a try. However, neither confirms (or maybe I missed 
it) if I can manage/manupulate the zfs datasets from within the jail -- 
and that seems to be the logical approach based on various emails on the 
mailing lists. So, what I am really after is some kind of a 
pointer/direction, maybe even a rough sketch of a how-to, that would 
help in getting started at least. I am not new to jails -- it is just 
that so far most of my jails were on UFS systems and I never encountered 
this issue of data mismatch between what the Jail can see and what the 
host can see.

Thanks again
SK