Re: [PATCH v2 3/3] installer: Run in unattended mode only on ttyS0

[Uladzimir Bely <ubely@ilbers.de>]

On Tue, 2025-03-18 at 08:08 +0100, Jan Kiszka wrote:
> On 18.03.25 07:33, Uladzimir Bely wrote:
> > On Tue, 2025-03-18 at 07:29 +0100, Jan Kiszka wrote:
> > > On 18.03.25 07:25, 'Jan Kiszka' via isar-users wrote:
> > > > On 18.03.25 07:10, Uladzimir Bely wrote:
> > > > > This fixes race between two unattended installer instances
> > > > > running
> > > > > on serial "ttyS0" and graphic "tty1" terminals.
> > > > > 
> > > > > While one of them starts writing the disk, another one fails
> > > > > and schedules reboot in 60 seconds. Depending on build
> > > > > machine
> > > > > performance we can get incomplete installation and broken
> > > > > target
> > > > > filesystem.
> > > > > 
> > > > > Signed-off-by: Uladzimir Bely <ubely@ilbers.de>
> > > > > ---
> > > > >  .../deploy-image/files/usr/bin/deploy-image-wic.sh         
> > > > > | 6
> > > > > ++++++
> > > > >  1 file changed, 6 insertions(+)
> > > > > 
> > > > > diff --git a/meta-isar/recipes-installer/deploy-
> > > > > image/files/usr/bin/deploy-image-wic.sh b/meta-isar/recipes-
> > > > > installer/deploy-image/files/usr/bin/deploy-image-wic.sh
> > > > > index 7f552eee..bd580694 100755
> > > > > --- a/meta-isar/recipes-installer/deploy-
> > > > > image/files/usr/bin/deploy-image-wic.sh
> > > > > +++ b/meta-isar/recipes-installer/deploy-
> > > > > image/files/usr/bin/deploy-image-wic.sh
> > > > > @@ -10,6 +10,12 @@ SCRIPT_DIR=$( dirname -- "$( readlink -f -
> > > > > -
> > > > > "$0"; )"; )
> > > > >  
> > > > >  . ${SCRIPT_DIR}/../lib/deploy-image-wic/handle-config.sh
> > > > >  
> > > > > +if $installer_unattended; then
> > > > > +    if [ "$(tty)" != "/dev/ttyS0" ]; then
> > > > 
> > > > This is wrong. "ttyS0" is target-specific. We need a different,
> > > > generic
> > > > mechanism to detect multiple executions.
> > > > 
> > > > Jan
> > > > 
> > > > > +        echo "Disable unattended mode on $(tty), it's active
> > > > > on
> > > > > /dev/ttyS0"
> > > > > +        installer_unattended=0
> > > 
> > > And this would be also wrong.
> > > 
> > > But all this does not make sense yet. We have a single service
> > > that
> > > is
> > > supposed to run a single script. I don't see why systemd should
> > > instantiate the service multiple times. Is our service file
> > > incorrect?
> > > 
> > 
> > The service itself is correct, the problem is that it's run twice.
> > 
> > https://github.com/ilbers/isar/blob/master/meta-isar/recipes-installer/deploy-image-service/deploy-image-service.bb#L19-L20
> > 
> > For non-unattended mode it doesn't matter, but in unattended mode
> > one
> > of instances fails and schedules rebooting.
> > 
> 
> Ah, now I remember.
> 
> But, again, we need a proper fix here. Re-entrance needs to be
> detected,
> the core copy job needs to be run only once. And all other entrances
> of
> the script skip over the copying core or otherwise wait at the same
> dialog that semi-unattended modes may show.
> 
> Jan
> 

OK, I see.

So, there are two ways to deal with the issue:

1. Make one of terminals (for example, first virtual console ttyS1)
main one, e.g.:

INSTALLER_UNATTENDED_CONSOLE ?= "ttyS1"

And refer to this variable instead of hardcoded value.

2. Unattended installation will be done by the service which was the
first one in the race (first who run bmaptool and locked e.g.
/dev/sda). Other services just should not trigger reboot in this case,
that means "reboot" should be moved from service unit to script again.

As for me, I would prefer option 1 since it's more predictable.


-- 
Best regards,
Uladzimir.

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