[systemd-devel] Stricter handling of failing mounts during boot under systemd - crap idea !

[jon]

On Mon, 2015-06-29 at 20:50 +0200, Lennart Poettering wrote:
> On Mon, 29.06.15 19:20, jon (jon at jonshouse.co.uk) wrote:
> 
> > Reversing the logic by adding a "mustexist" fstab option and keeping the
> > default behaviour would fix it.
> 
> At this time, systemd has been working this way for 5y now. The
> behaviour it implements is also the right behaviour I am sure, and the
> "nofail" switch predates systemd even.
I disagree strongly.  As I said the "option" did not do anything... so
the change only really happened when systemd coded it. Very people are
using systemd, so this change may be "stable old code" in your world, in
my world it "new" and its behaviour is "wrong" !


>  Hence I am very sure the
> default behaviour should stay the way it is.
Your default behaviour or mine !

Many people that I know who run linux for real work have been using
systemd for 5 mins, most have yet to discover it at all !

The first I knew about is when Debian adopted it, I have been using
systemd for a few hours only. It may be your 5 year old pet, but to me
it just a new set of problems to solve.

I normally install machines with Debian stable,  I am just discovering
systemd for the first time.

> 
> > Bringing up networking/sshd in parallel to the admin shell would also
> > mitigate my issue....
> 
> That's a distro decision really. Note though that many networking
> implementations as well as sshd are actually not ready to run in
> early-boot, like the emergecny mode is. i.e. they assume access to
> /var works, use PAM, and so on, which you better avoid if you want to
> run in that boot phase.

Hmmm ... it used to be possible with telnetd, so I suspect it is still
possible with sshd.

The logic would be to bring networking up (as configured, but no
services).  start sshd (as it is configured) but with say an extra flag
to bring up a new mode ....

"sshd -adminmode" for example.


Then from the client:

$ ssh anyolduser at myfailedmachine

This machine is administration mode and may have failed to fully boot.
Please enter the root password to enter a remote administration shell. 
password:

(admin) #
(admin) # fix it
(admin) # reboot


Requirements:

1) ssh-client can display a messages before login prompt like good old
telnet used to - maybe (shock) just plain text, not sure it can do this
- but hey more code changes are fun, right ... 

2) The new ssh server 'admin' mode would need to be much more stateless
like good old telnetd used to be.

This is the "problem" with systemd, by changing one small behaviour it
now requires many many changes to get a truly useful system behaviour
back.

> > I can see that both proposed solutions have issues, but I suspect I am
> > not the only one who will not be pleased about this behaviour change.
> > 
> > Changes seem to made with a bias towards desktops or larger data
> > centres, but what about the people using discarded PCs and maintaining
> > small servers, lots of these floating around smaller organisations. 
> 

> As you might know my company cares about containers, big servers
> primarily, while I personally run things on a laptop and a smaller
> server on the Internet. Hence believe me that I usually care about
> laptop setups at least as much as for server setups.
Nope, did not know that, interesting.

I on the other hand normally admin small servers built from old PC
hardware or fully embedded ARM devices.