[mythtv-users] Best options/howto for diskless frontends

Tim Phipps phipps-hutton at sky.com
Mon Nov 26 12:57:13 UTC 2012


Quoting Paul Gardiner <lists at glidos.net>:

> On 26/11/2012 11:46, Tim Phipps wrote:
>> Your frontend will have to be shutdown while you do this otherwise there
>> is a chance of it panicking when you change/delete the contents of
>> programs/libraries. It doesn't damage anything but not nice to watch.
>
> Oh yes, that's a good point. :-) Not a problem. The frontend is mostly
> off when I'm fiddling. The thing that I'm expecting to be a problem
> is the client running 32bit while the server runs 64bit. Am I right
> that rules out some of the approaches to accessing the exported
> client installation from the server?
>

You won't be able to share the executables so you will need a private  
filesystem for the frontend to boot from, I'm not sure how you will  
get to populate it either without starting with a local disk on the  
frontend and then copying it to the server.

>>>
>>> 5) To be able to switch off the diskless machine without
>>> shutting down.
>>
>> This is certainly easier with diskless booting, just hit the big white
>> switch on the wall!
>
> No risk of leaving the servers exported files in a mess?

Plenty of risk but you won't break the filesystem on the server so it  
will be individual files that will get messed up. I've not had any  
problems with MythTV frontend as the only state is the settings and  
that is stored in mysql. I have had problems with firefox getting  
locked with a diskless desktop system but that their crappy embedded  
database at fault.

>
>> With an SSD you could run with a read-only root. Once you have the
>> config sorted add "ro" to the /etc/fstab options for the root directory
>> and reboot. I use this with Debian and once I'd figured out how to
>> divert some files/directories to writeable NFS mounts or tmpfs it's
>> fine. You need a tmpfs for /tmp, /var/run and /var/lock and either
>> divert /var/log to /tmp or NFS. After that there are a bunch of files
>> that need to be symlinked elsewhere but you will find those when you
>> boot readonly.
>
> Oh right! So no need for unionfs or anything complicated. Just a few
> directories to target... although I worry that leaving unfinalised
> stuff in /var/lock could cause problems... don't know really - I'm
> guessing.
>

If you have /var/lock on a tmpfs there will be nothing left after a  
reboot so nothing to worry about!


Cheers,
Tim.




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