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systemd/sysctl.d/50-default.conf

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sysctl: add 50-default.conf
2013-03-15 19:11:56 +04:00
# This file is part of systemd.
#
# systemd is free software; you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2.1 of the License, or
# (at your option) any later version.
# See sysctl.d(5) and core(5) for for details.
sysctl: default - add safe sysrq options
2013-03-15 22:30:53 +04:00
# System Request functionality of the kernel (SYNC)
kernel.sysrq = 16
sysctl: add 50-default.conf
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# Append the PID to the core filename
kernel.core_uses_pid = 1
# Source route verification
net.ipv4.conf.default.rp_filter = 1
sysctl: always write net.ipv4.conf.all.xyz= in addition to net.ipv4.conf.default.xyz= Otherwise we have a boot-time race, where interfaces that popped up after the sysctl service would get the settings applied, but all others wouldn't.
2014-08-15 14:07:33 +04:00
net.ipv4.conf.all.rp_filter = 1
sysctl: add 50-default.conf
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# Do not accept source routing
net.ipv4.conf.default.accept_source_route = 0
sysctl: always write net.ipv4.conf.all.xyz= in addition to net.ipv4.conf.default.xyz= Otherwise we have a boot-time race, where interfaces that popped up after the sysctl service would get the settings applied, but all others wouldn't.
2014-08-15 14:07:33 +04:00
net.ipv4.conf.all.accept_source_route = 0
sysctl: add 50-default.conf
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sysctl.d: enable promote_secondaries by default Without this, secondary addresses would get deleted when the primary one is. This is not the desired behavior when one would like to transition from one address to another in the same subnet (such as when a new IP address is given over DHCP). In networkd, when given a new IP over DHCP we will add it, without explicitly removing the old one first (and hence never have a window without an IP address configured). Assuming the addresses are in the same subnet, that means that the old address is the primary and the new address is the secondary one. Once the old address expires, the kernel will drop it. With the old behavior this means that both addresses would be lost, which is clearly not what we want. With the new behavior, only the old address is lost, and the new one is promoted to primary. Reported by Michael Olbrich <m.olbrich@pengutronix.de>
2014-07-25 13:08:23 +04:00
# Promote secondary addresses when the primary address is removed
net.ipv4.conf.default.promote_secondaries = 1
sysctl: always write net.ipv4.conf.all.xyz= in addition to net.ipv4.conf.default.xyz= Otherwise we have a boot-time race, where interfaces that popped up after the sysctl service would get the settings applied, but all others wouldn't.
2014-08-15 14:07:33 +04:00
net.ipv4.conf.all.promote_secondaries = 1
sysctl.d: enable promote_secondaries by default Without this, secondary addresses would get deleted when the primary one is. This is not the desired behavior when one would like to transition from one address to another in the same subnet (such as when a new IP address is given over DHCP). In networkd, when given a new IP over DHCP we will add it, without explicitly removing the old one first (and hence never have a window without an IP address configured). Assuming the addresses are in the same subnet, that means that the old address is the primary and the new address is the secondary one. Once the old address expires, the kernel will drop it. With the old behavior this means that both addresses would be lost, which is clearly not what we want. With the new behavior, only the old address is lost, and the new one is promoted to primary. Reported by Michael Olbrich <m.olbrich@pengutronix.de>
2014-07-25 13:08:23 +04:00
sysctl.d: default to fq_codel, fight bufferbloat Quoting from Jon Corbet's report of Stephen Hemminger's talk at Linux Plumbers Conference 2014 (https://lwn.net/Articles/616241/): [...] So Stephen encouraged everybody to run a command like: sysctl -w net.core.default_qdisc=fq_codel That will cause fq_codel to be used for all future connections [Qdiscs apply to interfaces, not connections. Pointed out by TomH in the article comments. -- mschmidt] (up to the next reboot). Unfortunately, the default queuing discipline cannot be changed, since it will certainly disturb some user's workload somewhere. Let's have the recommended default in systemd. Thanks to Dave Täht for advice and the summary at https://lists.bufferbloat.net/pipermail/cerowrt-devel/2014-October/003701.html
2014-10-16 15:49:04 +04:00
# Fair Queue CoDel packet scheduler to fight bufferbloat
net.core.default_qdisc = fq_codel
sysctl: add 50-default.conf
2013-03-15 19:11:56 +04:00
# Enable hard and soft link protection
fs.protected_hardlinks = 1
fs.protected_symlinks = 1
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