man: document the network interface size limits --network-veth= enforces

Fixes: #10721
This commit is contained in:
Lennart Poettering 2019-03-13 16:24:59 +01:00
parent fba10579f1
commit 6cc68362d5
1 changed files with 17 additions and 5 deletions

View File

@ -614,6 +614,16 @@
<para>Note that <option>--network-veth</option> is the default if the
<filename>systemd-nspawn@.service</filename> template unit file is used.</para>
<para>Note that on Linux network interface names may have a length of 15 characters at maximum, while
container names may have a length up to 64 characters. As this option derives the host-side interface
name from the container name the name is possibly truncated. Thus, care needs to be taken to ensure
that interface names remain unique in this case, or even better container names are generally not
chosen longer than 12 characters, to avoid the truncation. Alternatively, the
<option>--network-veth-extra=</option> option may be used, which allows free configuration of the
host-side interface name independently of the container name — but might require a bit more
additional configuration in case bridging in a fashion similar to <option>--network-bridge=</option>
is desired.</para>
</listitem>
</varlistentry>
@ -635,11 +645,13 @@
<varlistentry>
<term><option>--network-bridge=</option></term>
<listitem><para>Adds the host side of the Ethernet link created with <option>--network-veth</option> to the
specified Ethernet bridge interface. Expects a valid network interface name of a bridge device as
argument. Note that <option>--network-bridge=</option> implies <option>--network-veth</option>. If this option
is used, the host side of the Ethernet link will use the <literal>vb-</literal> prefix instead of
<literal>ve-</literal>.</para></listitem>
<listitem><para>Adds the host side of the Ethernet link created with <option>--network-veth</option>
to the specified Ethernet bridge interface. Expects a valid network interface name of a bridge device
as argument. Note that <option>--network-bridge=</option> implies <option>--network-veth</option>. If
this option is used, the host side of the Ethernet link will use the <literal>vb-</literal> prefix
instead of <literal>ve-</literal>. Regardless of the used naming prefix the same network interface
name length limits imposed by Linux apply, along with the complications this creates (for details see
above).</para></listitem>
</varlistentry>
<varlistentry>