Re: [systemd-devel] Impact when not loading ipv6 and autofs kernel module ...
On Wed, 14.08.13 16:43, Hoyer, Marko (ADITG/SW2) (mho...@de.adit-jv.com) wrote: For what is systemd using the loopback so that it has to set it up so early? Is there any impact when I'm setting up the loopback later. We are probably in a situation where we need ipv4 for general purposes and ipv6 for only special ones. So we'd like to set up ipv6 later for performance reasons, which concerns especially the module loading. Humm, I doubt that initializing IPv6 early will really slow things down for you. The reason we initialize the loopback device this early is simply that most userspace code simply expects it to be there, and working, and it's absolutely trivial and fast to do, so we just do it by default, so that it just works and is nothing the user can manually configure and where we then have to parse configuraiton files and have another distinct component running late in boot dealing with this and so on... It's really something we want to be quick, and always done and non-configurable and since its a triviality to do we just do it in PID 1... Lennart -- Lennart Poettering - Red Hat, Inc. ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] Impact when not loading ipv6 and autofs kernel module ...
-Original Message- From: Lennart Poettering [mailto:lenn...@poettering.net] Sent: Friday, August 09, 2013 5:49 PM To: Hoyer, Marko (ADITG/SW2) Cc: systemd-devel@lists.freedesktop.org Subject: Re: [systemd-devel] Impact when not loading ipv6 and autofs kernel module ... On Wed, 07.08.13 11:24, Hoyer, Marko (ADITG/SW2) (mho...@de.adit-jv.com) wrote: Hello systemd developers, I found that systemd automatically tries to load ipv6 and autofs kernel modules, when they are not compiled in. Could you give me a hint what is not working, when they are neither provided as kernel modules nor compiled in? In case of autofs I found that automount units are not working any more (I would have expected this). Without ipv6 I can't find any problems by now. So: 1. Is there any other impact but the described one when the autofs kernel feature is missing? No. .automount units become unavailable, but that's all. 2. What impact do I have to expect in case the kernel does not provide ipv6 functionality? Well, support for IPv6 goes away, of course. The reason we explicitly load the module at early boot is that we try to configure the loopback device to ::1, but that can only work if IPv6 is available in the kernel. Doing this kind of loopback configuration of IPv6 however is not hooked up to the kernel-side auto-loading of ipv6.ko hence we load it explicitly from usersapce. Lennart Thx for the input. For what is systemd using the loopback so that it has to set it up so early? Is there any impact when I'm setting up the loopback later. We are probably in a situation where we need ipv4 for general purposes and ipv6 for only special ones. So we'd like to set up ipv6 later for performance reasons, which concerns especially the module loading. -- Lennart Poettering - Red Hat, Inc. Best regards Marko Hoyer Software Group II (ADITG/SW2) Tel. +49 5121 49 6948 ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
[systemd-devel] Impact when not loading ipv6 and autofs kernel module ...
Hello systemd developers, I found that systemd automatically tries to load ipv6 and autofs kernel modules, when they are not compiled in. Could you give me a hint what is not working, when they are neither provided as kernel modules nor compiled in? In case of autofs I found that automount units are not working any more (I would have expected this). Without ipv6 I can't find any problems by now. So: 1. Is there any other impact but the described one when the autofs kernel feature is missing? 2. What impact do I have to expect in case the kernel does not provide ipv6 functionality? Thx for any input. Best regards Marko Hoyer Advanced Driver Information Technology GmbH Software Group II (ADITG/SW2) Robert-Bosch-Str. 200 31139 Hildesheim Germany Tel. +49 5121 49 6948 Fax +49 5121 49 6999 mho...@de.adit-jv.com ADIT is a joint venture company of Robert Bosch GmbH/Robert Bosch Car Multimedia GmbH and DENSO Corporation Sitz: Hildesheim, Registergericht: Amtsgericht Hildesheim HRB 3438 Geschäftsführung: Wilhelm Grabow, Katsuyoshi Maeda ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] Impact when not loading ipv6 and autofs kernel module ...
On Wed, Aug 7, 2013 at 1:24 PM, Hoyer, Marko (ADITG/SW2) mho...@de.adit-jv.com wrote: 2. What impact do I have to expect in case the kernel does not provide ipv6 functionality? I think the main problem is in case you were to somehow insmod the ipv6 module after boot, in which case it probably won't be set up correctly. Maybe someone else know of other problems? Cheers, Tom ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
