Shall we fork Debian? • Hacker News Board

Re: Shall we fork Debian?

#281

Post by cbsmith » Wed, Oct 22, 2014, 12:01 AM UTC

EmanueleAina wrote: post #280

cbsmith wrote: post #275

Earlier quoted context omitted.

dbus was already there. How do you think udev works?

To be fair, udev communicates over netlink. :) Only in the future it may use kdbus for some purposes (eg. uploading firmware blobs), but this will only affect internal interfaces. On the other hand, systemd does not require the D-Bus daemon when you're launching systemctl it as root, the D-Bus daemon is only needed to route the call when used by unprivileged users. When used as root, systemctl connects to the PID1 so…

> To be fair, udev communicates over netlink. :)

To be fair, udev communicates with the kernel via netlink. All the userspace notifications are done via dbus. So dbus was already part of the equation whether people realize it or not.

http://blogas.sysadmin.lt/?p=141

Re: Shall we fork Debian?

#282

Post by csirac2 » Wed, Oct 22, 2014, 12:56 AM UTC

cbsmith wrote: post #275

csirac2 wrote: post #254

Earlier quoted context omitted.

Yet it seems installing systemd drags dbus and bunch of other dependencies in with it... tomato, potato.

dbus was already there. How do you think udev works?

I build debian chroots with sysv init. Edit: they have libdbus, but aren't running the dbus daemon, but are running udevd.

Re: Shall we fork Debian?

#283

Post by EmanueleAina » Wed, Oct 22, 2014, 10:05 PM UTC

cbsmith wrote: post #281

EmanueleAina wrote: post #280

Earlier quoted context omitted.

To be fair, udev communicates over netlink. :) Only in the future it may use kdbus for some purposes (eg. uploading firmware blobs), but this will only affect internal interfaces. On the other hand, systemd does not require the D-Bus daemon when you're launching systemctl it as root, the D-Bus daemon is only needed to route the call when used by unprivileged users. When used as root, systemctl connects to the PID1 so…

> To be fair, udev communicates over netlink. :) To be fair, udev communicates with the kernel via netlink. All the userspace notifications are done via dbus. So dbus was already part of the equation whether people realize it or not. http://blogas.sysadmin.lt/?p=141

Are you sure? IIRC it was HAL that picked the kernel events and converted to D-Bus signals, but it has been deprecated a long time ago.

I gave a cursory glance to the systemd/src/udev files and found no mention of dbus.

Re: Shall we fork Debian?

#284

Post by csirac2 » Wed, Oct 22, 2014, 11:33 PM UTC

cbsmith wrote: post #274

csirac2 wrote: post #262

Earlier quoted context omitted.

The trigger is the appearance of the volume. If the mounter actions crypttab properly it'll run the keyscript which challenges the smartcard or TPM or USB crypt token or some combination thereof, which in turn provides the response to cryptsetup. By default nothing happens when you insert a smartcard; if the keyscript tries to run without the smartcard it will retry, timeout, and eventually fall back to askpass. If t…

> The trigger is the appearance of the volume. I'm sorry. I wasn't clear. I was asking about the work that gets you to the point where the volume appears. You don't necessarily have a device file for the volume, so something needs to be ready to handle that logic when the device is inserted, then when it has figured that out, you have to notify the automounter that it is time to go to work (or not), etc. Now add logi…

I think I get your point, but for what it's worth the sysvinit cryptroot/crypttab setup has worked seamlessly for servers for years. Basically if keyscript fails (smart card not available or challenge material not available or TPM won't unseal) it falls back to ask pass on a TTY with the hopes that you can type something in.

I also do appreciate the systemd features for mobile and desktop devices.

But the sysvinit mechanisms aren't rendered completely irrelevant by systemd; the sheer stupid dumb luck of the the thing is actually deterministic and repeatable in my experience. systemd migrations have exposed hidden dependencies I hadn't previously had to worry about between services, which is good in one way, but not necessarily good in other ways (transient intermittent failures which never occurred under sysv).

Yes, it's unfair to blame systemd for poorly defined services - I do like the concept systemd is offering in that respect. But if I have servers in the rack which have smart cards in them that I know are always attached except for very rare events where a sysadmin will be dealing with things, I don't think there's harm in a 4-line shell script failing maybe once or twice in a server's lifetime if it means not having to maintain bespoke C programs for years and years