diff options
| -rw-r--r-- | man/systemd.link.xml | 74 |
1 files changed, 65 insertions, 9 deletions
diff --git a/man/systemd.link.xml b/man/systemd.link.xml index 7594c4996e..af9799e8c0 100644 --- a/man/systemd.link.xml +++ b/man/systemd.link.xml @@ -242,9 +242,11 @@ <listitem> <para>An ordered, space-separated list of policies by which the interface name should be set. <varname>NamePolicy=</varname> may be disabled by specifying <option>net.ifnames=0</option> on the - kernel command line. Each of the policies may fail, and the first successful one is used. The name + kernel command line. Each of the policies may fail, and the first successful one is used. The name is not set directly, but is exported to udev as the property <option>ID_NET_NAME</option>, which - is, by default, used by a udev rule to set <varname>NAME</varname>. The available policies are: + is, by default, used by a + <citerefentry><refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum></citerefentry>, + rule to set <varname>NAME</varname>. The available policies are: </para> <variablelist> @@ -312,11 +314,10 @@ <varlistentry> <term><varname>Name=</varname></term> <listitem> - <para>The interface name to use in case all the - policies specified in - <varname>NamePolicy=</varname> fail, or in case - <varname>NamePolicy=</varname> is missing or - disabled.</para> + <para>The interface name to use. This option has lower precedence than + <varname>NamePolicy=</varname>, so for this setting to take effect, <varname>NamePolicy=</varname> + must either be unset, empty, disabled, or all policies configured there must fail. Also see the + example below with <literal>Name=dmz0</literal>.</para> <para>Note that specifying a name that the kernel might use for another interface (for example <literal>eth0</literal>) is dangerous because the @@ -618,8 +619,7 @@ MACAddressPolicy=persistent</programlisting> <example> <title>/etc/systemd/network/10-dmz.link</title> - <para>This example assigns the fixed name - <literal>dmz0</literal> to the interface with the MAC address + <para>This example assigns the fixed name <literal>dmz0</literal> to the interface with the MAC address 00:a0:de:63:7a:e6:</para> <programlisting>[Match] @@ -627,6 +627,62 @@ MACAddress=00:a0:de:63:7a:e6 [Link] Name=dmz0</programlisting> + + <para><varname>NamePolicy=</varname> is not set, so <varname>Name=</varname> takes effect. We use the + <literal>10-</literal> prefix to order this file early in the list. Note that it needs to before + <literal>99-link</literal>, i.e. it needs a numerical prefix, to have any effect at all.</para> + </example> + + <example> + <title>Debugging <varname>NamePolicy=</varname> assignments</title> + + <programlisting>$ sudo SYSTEMD_LOG_LEVEL=debug udevadm test-builtin net_setup_link /sys/class/net/hub0 +… +Parsed configuration file /usr/lib/systemd/network/99-default.link +Parsed configuration file /etc/systemd/network/10-eth0.link +ID_NET_DRIVER=cdc_ether +Config file /etc/systemd/network/10-eth0.link applies to device hub0 +link_config: autonegotiation is unset or enabled, the speed and duplex are not writable. +hub0: Device has name_assign_type=4 +Using default interface naming scheme 'v240'. +hub0: Policies didn't yield a name, using specified Name=hub0. +ID_NET_LINK_FILE=/etc/systemd/network/10-eth0.link +ID_NET_NAME=hub0 +…</programlisting> + + <para>Explicit <varname>Name=</varname> configuration wins in this case.</para> + + <programlisting>sudo SYSTEMD_LOG_LEVEL=debug udevadm test-builtin net_setup_link /sys/class/net/enp0s31f6 +… +Parsed configuration file /usr/lib/systemd/network/99-default.link +Parsed configuration file /etc/systemd/network/10-eth0.link +Created link configuration context. +ID_NET_DRIVER=e1000e +Config file /usr/lib/systemd/network/99-default.link applies to device enp0s31f6 +link_config: autonegotiation is unset or enabled, the speed and duplex are not writable. +enp0s31f6: Device has name_assign_type=4 +Using default interface naming scheme 'v240'. +enp0s31f6: Policy *keep*: keeping existing userspace name +enp0s31f6: Device has addr_assign_type=0 +enp0s31f6: MAC on the device already matches policy *persistent* +ID_NET_LINK_FILE=/usr/lib/systemd/network/99-default.link +… +</programlisting> + + <para>In this case, the interface was already renamed, so the <option>keep</option> policy specified as + the first option in <filename noindex='true'>99-default.link</filename> means that the existing name is + preserved. If <option>keep</option> was removed, or if were in boot before the renaming has happened, + we might get the following instead:</para> + + <programlisting>enp0s31f6: Policy *path* yields "enp0s31f6". +enp0s31f6: Device has addr_assign_type=0 +enp0s31f6: MAC on the device already matches policy *persistent* +ID_NET_LINK_FILE=/usr/lib/systemd/network/99-default.link +ID_NET_NAME=enp0s31f6 +… +</programlisting> + + <para>Please note that the details of output are subject to change.</para> </example> <example> |