what 3rd party boot mgr is required to boot multiple freebsd versions?

[Toomas Soome]

> On 17. Mar 2020, at 15:51, Matthew Seaman <matthew at FreeBSD.org> wrote:
> 
> On 17/03/2020 12:58, Florian Limberger wrote:
>> On 16.03.20 23:33, Chris wrote:
>> 
>>> For the record. I'm *only* using FreeBSD in this situation. I
>>> only mentioned Windows above, for the use of it's boot manager.
>> 
>> If you only use FreeBSD, and also use ZFS, you might find beadm[1]
>> interesting.
>> 
>> [1]: https://www.freshports.org/sysutils/beadm
>> 
> 
> Did you know that the system now comes with bectl(8) which is very
> similar to beadm?  As far as I can tell, the biggest difference is that
> if you have more than one ZFS in your boot environment then:
> 
>    beadm create FOO
> 
> is actually equivalent to
> 
>    bectl create -r FOO
> 
> ie. turning on the recursive functionality in bectl.
> 
> However, this is not really what the OP was asking about.  As I
> understand it, they were looking for something that would allow choosing
> between several independent installations of different versions of
> FreeBSD, rather than having multiple environments in the same
> installation.  You can achieve pretty much the same effect though --
> there is a boot menu option to switch between BEs.  You would have to
> manage any ported software between the different OS versions, perhaps by
> including /usr/local and /var/db/pkg are both parts of your BEs.
> 
> 	Cheers,
> 
> 	Matthew
> 

BE’s can solve some scenarios. However, it is easy to add support for few more. The current BE menu is populated automatically from the zfs. However, it is also simple task to add a file parser to it and read menu file with entries with different pool (we only need to activate such entries same way as it is currently done for “normal” BE, or entries with chain load). Read this menu file first and zfs BE list after, and you have BE menu with manual and automatic entries. Can be implemented within few hours. 

rgds,
Toomas