Systemd/networkd: Difference between revisions

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{{Systemd/breadcrumb}}
{{DISPLAYTITLE:systemd-networkd}}
{{DISPLAYTITLE:systemd-networkd}}
[https://www.freedesktop.org/software/systemd/man/systemd-networkd.html systemd-networkd] is the network[[Category: Networking]] configuration component of the [[systemd]][[Category:systemd]] software suite. It is well integrated into NixOS below {{Nixos:option|systemd.network}} and should be preferred over {{Nixos:option|networking.interfaces}} options for most use cases, since it receives far superior maintenance.
[https://www.freedesktop.org/software/systemd/man/systemd-networkd.html systemd-networkd] is the network configuration component of the [[systemd]][[Category:systemd]] software suite. It is well integrated into NixOS below {{Nixos:option|systemd.network}} and should be preferred over {{Nixos:option|networking.interfaces}} options for most use cases, since it receives far superior maintenance.


Configuration for networkd is split into three sections.
Configuration for networkd is split into three sections.
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These use cases are better served by [[NetworkManager]] and its various frontends, that provides a better integrated user experience for various desktop systems.
These use cases are better served by [[NetworkManager]] and its various frontends, that provides a better integrated user experience for various desktop systems.


{{Note|Both systemd-networkd and NetworkManager can exist in parallel on the same machine,
{{Note|Both systemd-networkd and NetworkManager can exist in parallel on the same machine, when they manage a distinct set of interfaces. If upstream connectivity is managed by NetworkManager (for example, NM handles wifi and networkd does VM networking), set {{Nixos:option|systemd.network.wait-online.enable}} to false so that boot isn't blocked on connectivity that networkd will never provide.}}
when they manage a distinct set of interfaces.}}


=== Enabling ===
=== Enabling ===
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</nowiki>}}
</nowiki>}}


Note that we usually prefix the configuration file with a number. This can be important, because networkd collects all available configuration files, then sorts them alphabetically, and uses the first match for each interface as its configuration. This happens separately for <code>.link</code>, <code>.netdev</code> and <code>.network</code> files, so that you can have one configuration of each type per interface.
Note that we usually prefix the configuration file with a number. This can be important, because networkd collects all available configuration files, then sorts them alphanumerically, and uses the first match for each interface as its configuration. This happens separately for <code>.link</code>, <code>.netdev</code> and <code>.network</code> files, so that you can have one configuration of each type per interface.
 
=== Debugging ===
 
When things don't work as expected, the journal for <code>systemd-networkd.service</code> should be consulted. Unfortunately, by default the log is not very useful in its default loglevel. Increasing the loglevel can be done using the <code>SYSTEMD_LOG_LEVEL</code> environment variable.
 
<syntaxhighlight lang="nix">
systemd.services."systemd-networkd".environment.SYSTEMD_LOG_LEVEL = "debug";
</syntaxhighlight>


=== Limitations ===
=== Limitations ===
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<syntaxhighlight lang="nix">
<syntaxhighlight lang="nix">
systemd.network."50-enp3s0" = {
systemd.network.networks."50-enp3s0" = {
   matchConfig.Name = "enp3s0";
   matchConfig.Name = "enp3s0";
   # acquire a DHCP lease on link up
   # acquire a DHCP lease on link up
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     matchConfig.Name = "enp1s0";
     matchConfig.Name = "enp1s0";
     address = [
     address = [
        # configure addresses including subnet mask
      # configure addresses including subnet mask
        "192.0.2.100/24"
      "192.0.2.100/24"
        "2001:DB8::2/64"
      "2001:DB8::2/64"
     ];
     ];
     routes = [
     routes = [
       # create default routes for both IPv6 and IPv4
       # create default routes for both IPv6 and IPv4
       { routeConfig.Gateway = "fe80::1"; }
       { Gateway = "fe80::1"; }
       { routeConfig.Gateway = "192.0.2.1"; }
       { Gateway = "192.0.2.1"; }
       # or when the gateway is not on the same network
       # or when the gateway is not on the same network
       { routeConfig = {
       {
         Gateway = "172.31.1.1";
         Gateway = "172.31.1.1";
         GatewayOnLink = true;
         GatewayOnLink = true;
       }; }
       }
     ];
     ];
     # make the routes on this interface a dependency for network-online.target
     # make the routes on this interface a dependency for network-online.target
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VLANs can be configured on top of hardlinks as well as virtual links, like bonding interfaces. They provide separate logical networks over physical links.
VLANs can be configured on top of hardlinks as well as virtual links, like bonding interfaces. They provide separate logical networks over physical links.


In this example we tag two VLANs with Ids 10 and 20 on a physical link <code>enp1s0</code>. The VLAN interfaces become available <code>vlan10</code> and <code>vlan20</code> and can receive additional configuration.
In this example we tag two VLANs with Ids 10 and 20 on a physical link <code>enp1s0</code>. The VLAN interfaces become available as <code>vlan10</code> and <code>vlan20</code> and can receive additional configuration.


<syntaxhighlight lang="nix">
<syntaxhighlight lang="nix">
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         # tag vlan on this link
         # tag vlan on this link
         vlan = [
         vlan = [
           vlan10
           "vlan10"
           vlan20
           "vlan20"
         ];
         ];
        networkConfig.LinkLocalAddressing = "no";
        linkConfig.RequiredForOnline = "carrier";
       };
       };
       "40-vlan10" = {
       "40-vlan10" = {
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       # Configure the bridge for its desired function
       # Configure the bridge for its desired function
       "40-br0" = {
       "40-br0" = {
         matchConfig.Name ="br0";
         matchConfig.Name = "br0";
         bridgeConfig = {};
         bridgeConfig = {};
        # Disable address autoconfig when no IP configuration is required
        #networkConfig.LinkLocalAddressing = "no";
         linkConfig = {
         linkConfig = {
           # or "routable" with IP addresses configured
           # or "routable" with IP addresses configured
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=== Bonding ===
=== Bonding ===


Given two hardlinks <code>enp2s0</code> and <code>enp3s0</code> create a virtual <code>bond0</code> interface using Dynamic LACP (802.3ad), hashing outgoing packets using a packet's Layer3/4 (OSI Layer) information.
Given two hardlinks <code>enp2s0</code> and <code>enp3s0</code> create a virtual <code>bond0</code> interface using Dynamic LACP (802.3ad), hashing outgoing packets using a packet's layer 3/4 (network/transport layer in the OSI model) information.


<syntaxhighlight lang="nix">
<syntaxhighlight lang="nix">
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       "30-lan" = {
       "30-lan" = {
         matchConfig.Name = "lan";
         matchConfig.Name = "lan";
         address = [
         address = [ "2001:db8:1122:3344::1/64" ];
          "2001:db8:1122:3344::1/64"
        ];
         networkConfig = {
         networkConfig = {
           IPv6SendRA = true;
           IPv6SendRA = true;
         };
         };
         ipv6Prefixes = [ {
         ipv6Prefixes = [
          # Announce a static prefix
          {
          ipv6PrefixConfig.Prefix = "2001:db8:1122:3344::/64";
            # Announce a static prefix
         } ];
            ipv6PrefixConfig.Prefix = "2001:db8:1122:3344::/64";
          }
         ];
         ipv6SendRAConfig = {
         ipv6SendRAConfig = {
           # Provide a DNS resolver
           # Provide a DNS resolver
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         };
         };
       };
       };
    };
   };
   };
</syntaxhighlight>
</syntaxhighlight>
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* [https://gist.github.com/mweinelt/b78f7046145dbaeab4e42bf55663ef44 NixOS 22.11 VDSL Router (VLANs on top of Bonding, IPv6 Prefix-Delegation, pppd Integration)] by [https://github.com/mweinelt mweinelt]
* [https://gist.github.com/mweinelt/b78f7046145dbaeab4e42bf55663ef44 NixOS 22.11 VDSL Router (VLANs on top of Bonding, IPv6 Prefix-Delegation, pppd Integration)] by [https://github.com/mweinelt mweinelt]
[[Category:systemd]]
[[Category:Networking]]
Retrieved from "https://wiki.nixos.org/wiki/Systemd/networkd"