nixpkgs

History

Andreas Rammhold 55c09a884a nixos/modules/system/boot/networkd: enable socket activation Since `cd1dedac67` systemd-networkd has it's netlink socket created via a systemd.socket unit. One might think that this doesn't make much sense since networkd is just going to create it's own socket on startup anyway. The difference here is that we have configuration-time control over things like socket buffer sizes vs compile-time constants. For larger setups where networkd has to create a lot of (virtual) devices the default buffer size of currently 128MB is not enough. A good example is a machine with >100 virtual interfaces (e.g., wireguard tunnels, VLANs, …) that all have to be brought up during startup. The receive buffer size will spike due to all the generated message from the new interfaces. Eventually some of the message will be dropped since there is not enough (permitted) buffer space available. By having networkd start through / with a netlink socket created by systemd we can configure the `ReceiveBufferSize` parameter in the socket options without recompiling networkd. Since the actual memory requirements depend on hardware, timing, exact configurations etc. it isn't currently possible to infer a good default from within the NixOS module system. Administrators are advised to monitor the logs of systemd-networkd for `rtnl: kernel receive buffer overrun` spam and increase the memory as required. Note: Increasing the ReceiveBufferSize doesn't allocate any memory. It just increases the upper bound on the kernel side. The memory allocation depends on the amount of messages that are queued on the kernel side of the netlink socket.		2020-06-16 00:41:41 +02:00
..
administration
configuration	nixos/manual: document use of systemd to mount filesystems (#87684 )	2020-05-14 18:00:01 +02:00
development	nixos/doc: update stale fn name s/copy_file_from_host/copy_from_host/	2020-06-01 18:05:58 +10:00
installation	manual: use less weird way of installing nixos tools	2020-06-14 10:39:43 +02:00
release-notes	nixos/modules/system/boot/networkd: enable socket activation	2020-06-16 00:41:41 +02:00
.gitignore
default.nix
Makefile
man-configuration.xml
man-nixos-build-vms.xml
man-nixos-enter.xml
man-nixos-generate-config.xml
man-nixos-install.xml	nixos-install: 'nix build' -> nix-build	2020-05-07 13:12:29 +02:00
man-nixos-option.xml
man-nixos-rebuild.xml
man-nixos-version.xml
man-pages.xml
manual.xml
preface.xml
README
shell.nix

README

To build the manual, you need Nix installed on your system (no need
for NixOS). To install Nix, follow the instructions at

    https://nixos.org/nix/download.html

When you have Nix on your system, in the root directory of the project
(i.e., `nixpkgs`), run:

    nix-build nixos/release.nix -A manual.x86_64-linux

When this command successfully finishes, it will tell you where the
manual got generated.