The nix.daemonNiceLevel options allows for setting the nice level of the
Nix daemon process. On a modern Linux kernel with group scheduling the
nice level only affects threads relative to other threads in the same
task group (see sched(7)). Therefore this option has not the effect one
might expect.
The options daemonCPUSchedPolicy and daemonIOSchedClass are introduced
and the daemonIONiceLevel option renamed to daemonIOSchedPrority for
consistency. These options allow for more effective control over CPU
and I/O scheduling.
Instead of setting daemonNiceLevel to a high value to increase the
responsiveness of an interactive system during builds -- which would not
have the desired effect, as described above -- one could set both
daemonCPUSchedPolicy and daemonIOSchedClass to idle.
Don't worry, it's is true by default. But I think this is important to
have because NixOS indeed shouldn't need Nix at run time when the
installation is not being modified, and now we can verify that.
NixOS images that cannot "self-modify" are a legitamate
use-case that this supports more minimally. One should be able to e.g. do a
sshfs mount and use `nixos-install` to modify them remotely, or just
discard them and build fresh ones if they are run VMs or something.
The next step would be to make generations optional, allowing just
baking `/etc` and friends rather than using activation scripts. But
that's more involved so I'm leaving it out.
Before this commit, the `flake` option was typed with `types.unspecified`.
This type get's merged via [`mergeDefaultOption`](ebb592a04c/lib/options.nix (L119-L128)), which has a line
```nix
else if all isFunction list then x: mergeDefaultOption loc (map (f: f x) list)
```
`lib.isFunction` detects an attrs in the shape of `{__functor = ...}` as
a function and hence this line substitutes such attrs with a function
(f: f x).
If now, a flake input has a `__functor` as it's output, this will
coerce the once attrs to a function. This breaks a lot of things later
in the stack, for example a later `lib.filterAttrs seive <LAMBDA>` will
fail for obious reasons.
According to @infinisil, `types.unspecified` is due to deprecation. In
the meantime this PR provides a specific fix for the specific problem
discovered.
In newer versions of Nix (at least on 2.4pre20201102_550e11f) the
`extra-` prefix for config options received a special meaning and the
option `extra-sandbox-paths` isn't recognized anymore. This commit fixes
it.
It doesn't cause a behavior change when using older versions of Nix but
does cause an extra newline to appear in the config, thus changing the
hash.
As the only consequence of isSystemUser is that if the uid is null then
it's allocated below 500, if a user has uid = something below 500 then
we don't require isSystemUser to be set.
Motivation: https://github.com/NixOS/nixpkgs/issues/112647
Commit 5395397f removed the assertions from the buildMachines to
ensure that either system or systems is set for each buildmachine.
This patch re-implements those assertions.
The symptom is that if both system and systems are omitted, then the
/etc/machines file has the wrong number of columns and any attempt to
run a `nix` operation that has to perform a build will fail with a
`strtoull` exception.
The `platform` field is pointless nesting: it's just stuff that happens
to be defined together, and that should be an implementation detail.
This instead makes `linux-kernel` and `gcc` top level fields in platform
configs. They join `rustc` there [all are optional], which was put there
and not in `platform` in anticipation of a change like this.
`linux-kernel.arch` in particular also becomes `linuxArch`, to match the
other `*Arch`es.
The next step after is this to combine the *specific* machines from
`lib.systems.platforms` with `lib.systems.examples`, keeping just the
"multiplatform" ones for defaulting.
This reverts commits 9d0de0dc57,
27d2857a99. 'nix ping-store' is an
experimental command so it doesn't work in Nix 2.4 unless you set
'experimental-features = nix-command' in nix.conf.
Instead of making the configuration less portable by hard coding the number of
jobs equal to the cores we can also let nix set the same number at runtime.
This allows you to specify the system-wide flake registry. One use is
to pin 'nixpkgs' to the Nixpkgs version used to build the system:
nix.registry.nixpkgs.flake = nixpkgs;
where 'nixpkgs' is a flake input. This ensures that commands like
$ nix run nixpkgs#hello
pull in a minimum of additional store paths.
You can also use this to redirect flakes, e.g.
nix.registry.nixpkgs.to = {
type = "github";
owner = "my-org";
repo = "my-nixpkgs";
};
A centralized list for these renames is not good because:
- It breaks disabledModules for modules that have a rename defined
- Adding/removing renames for a module means having to find them in the
central file
- Merge conflicts due to multiple people editing the central file
In fact, don't create them at all because Nix does that automatically.
Also remove modules/programs/shell.nix because everything it did is
now done automatically by Nix.
Since version 2.3 (https://github.com/NixOS/nix/pull/2949 which was
cherry-picked to master) Nix issues a warning when --no-net wasn't
passed and there is no network interface. This commit adds the --no-net
flag to the nix.conf check such that no warning is issued.
