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authorKai Krakow <kai@kaishome.de>2019-06-24 00:24:18 +0200
committerLennart Poettering <lennart@poettering.net>2020-01-02 20:05:42 +0100
commitbc5ea049f29ce027bd1bcb2171547a9e31c9f512 (patch)
treec9991a36c20fc7747134c45e7a1515887697a456 /man/systemd.net-naming-scheme.xml
parentudev: move naming-scheme.[ch] into src/shared/ (diff)
downloadsystemd-bc5ea049f29ce027bd1bcb2171547a9e31c9f512.tar.xz
systemd-bc5ea049f29ce027bd1bcb2171547a9e31c9f512.zip
nspawn: Generate unique short veth names
This commit lowers the chance of having veth name conflicts for machines created with similar names. Replaces: #12865 Fixes: #13417
Diffstat (limited to 'man/systemd.net-naming-scheme.xml')
-rw-r--r--man/systemd.net-naming-scheme.xml24
1 files changed, 22 insertions, 2 deletions
diff --git a/man/systemd.net-naming-scheme.xml b/man/systemd.net-naming-scheme.xml
index 57987f16d7..126be320f6 100644
--- a/man/systemd.net-naming-scheme.xml
+++ b/man/systemd.net-naming-scheme.xml
@@ -46,6 +46,11 @@
devices based on those properties. See the description of <varname>NamePolicy=</varname> and
<varname>MACAddressPolicy=</varname> in
<citerefentry><refentrytitle>systemd.link</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+
+ <para>Note that while the concept of network interface naming schemes is primarily relevant in the
+ context of <filename>systemd-udevd.service</filename>, the
+ <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+ container manager also takes it into account when naming network interfaces, see below.</para>
</refsect1>
<refsect1>
@@ -329,7 +334,21 @@
<para>Previously two-letter interface type prefix was prepended to
<varname>ID_NET_LABEL_ONBOARD=</varname>. This is not done anymore.</para></listitem>
</varlistentry>
- </variablelist>
+
+ <varlistentry>
+ <term><constant>v245</constant></term>
+
+ <listitem><para>When
+ <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+ derives the name for the host side of the network interface created with
+ <option>--network-veth</option> from the container name it previously simply truncated the result
+ at 15 characters if longer (since that's the maximum length for network interface names). From now
+ on, for any interface name that would be longer than 15 characters the last 4 characters are set to
+ a 24bit hash value of the full interface name. This way network interface name collisions between
+ multiple similarly named containers (who only differ in container name suffix) should be less
+ likely (but still possible, since the 24bit hash value is very small).</para></listitem>
+ </varlistentry>
+ </variablelist>
<para>Note that <constant>latest</constant> may be used to denote the latest scheme known (to this
particular version of systemd.</para>
@@ -428,7 +447,8 @@ ID_NET_NAME_PATH=encf5f0</programlisting>
<para>
<citerefentry><refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
<citerefentry><refentrytitle>udevadm</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
- <ulink url="https://systemd.io/PREDICTABLE_INTERFACE_NAMES">Predictable Network Interface Names</ulink>
+ <ulink url="https://systemd.io/PREDICTABLE_INTERFACE_NAMES">Predictable Network Interface Names</ulink>,
+ <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>
</para>
</refsect1>