The new systemd in 19.09 gives an "Access Denied" error when doing
"systemctl daemon-reexec" on an 19.03 system. The fix is to use the
previous systemctl to signal the daemon to re-exec itself. This
ensures that users don't have to reboot when upgrading from NixOS
19.03 to 19.09.
Pretty useful for laptops. I use them with:
```
services.logind.lidSwitch = "suspend-then-hibernate";
environment.etc."systemd/sleep.conf".text = "HibernateDelaySec=8h";
```
boot.kernelPackages: check for conflicts
It's currently possible to set conflicting `boot.kernelPackages` several times.
Nixos now warns when this is the case instead of just picking one.
systemd provides two sysctl snippets, 50-coredump.conf and
50-default.conf.
These enable:
- Loose reverse path filtering
- Source route filtering
- `fq_codel` as a packet scheduler (this helps to fight bufferbloat)
This also configures the kernel to pass coredumps to `systemd-coredump`.
These sysctl snippets can be found in `/etc/sysctl.d/50-*.conf`,
and overridden via `boot.kernel.sysctl`
(which will place the parameters in `/etc/sysctl.d/60-nixos.conf`.
Let's start using these, like other distros already do for quite some
time, and remove those duplicate `boot.kernel.sysctl` options we
previously did set.
In the case of rp_filter (which systemd would set to 2 (loose)), make
our overrides to "1" more explicit.
Add support for custom device-tree files, and applying overlays to them.
This is useful for supporting non-discoverable hardware, such as sensors
attached to GPIO pins on a Raspberry Pi.
This adds handling for WASM binaries to binfmt’s emulatedSystems. To
enable, add this to your configuration:
boot.binfmt.emulatedSystems = [ "wasm32-wasi" ];
After rebuilding with nixos-rebuild switch, you can run wasm binaries
directly.
This is a refactor of how resolvconf is managed on NixOS. We split it
into a separate service which is enabled internally depending on whether
we want /etc/resolv.conf to be managed by it. Various services now take
advantage of those configuration options.
We also now use systemd instead of activation scripts to update
resolv.conf.
NetworkManager now uses the right option for rc-manager DNS
automatically, so the configuration option shouldn't be exposed.
