Before this commit updating /var/setuid-wrappers/ folder introduced
a small window where NixOS activation scripts could be terminated
and resulted into empty /var/setuid-wrappers/ folder.
That's very unfortunate because one might lose sudo binary.
Instead we use two atomic operations mv and ln (as described in
https://axialcorps.com/2013/07/03/atomically-replacing-files-and-directories/)
to achieve atomicity.
Since /var/setuid-wrappers is not a directory anymore, tmpfs mountpoints
were removed in installation scripts and in boot process.
Tested:
- upgrade /var/setuid-wrappers/ from folder to a symlink
- make sure /run/setuid-wrappers-dirs/ legacy symlink is really deleted
Both btrfs-progs and utillinux are ~5MB, we may discuss in future
to handle this better but I see no better way at the moment than
increaing purity in the install process.
OnCalendar entrys can be specified multiple times in a systemd timer, to
make more complex scheduling possible.
Tested by manually checking the timer generated by the following:
systemd = {
services.huhu = {
description = "meh";
wantedBy = [ "default.target" ];
serviceConfig.ExecStart = "/bin/sh -c 'printf HUHU!'";
startAt = [ "*:*:0/30" "*:0/1:15" ];
};
};
It prints HUHU to the log at seconds 0, 15 and 30 of each minute.
A new internal config option `fileSystems.<name>.early` is added to indicate
that the filesystem needs to be loaded very early (i.e. in initrd). They are
transformed to a shell script in `system.build.earlyMountScript` with calls to
an undefined `specialMount` function, which is expected to be caller-specific.
This option is used by stage-1, stage-2 and activation script to set up and
remount those filesystems. Options for them are updated according to systemd
defaults.
lustrate /ˈlʌstreɪt/ verb.
purify by expiatory sacrifice, ceremonial washing, or some other
ritual action.
- sudo touch /etc/NIXOS_LUSTRATE
⇒ on next reboot, during stage 1, everything but /nix and /boot
is moved to /old-root
- echo "etc/passwd" | sudo tee -a /etc/NIXOS_LUSTRATE
⇒ on next reboot, during stage 1, everything but /nix and /boot
is moved to /old-root; except /etc/passwd is copied back.
Useful for installing NixOS in place on another distro. For instance:
$ nix-env -iE '_: with import <nixpkgs/nixos> { configuration = {}; }; with config.system.build; [ nixos-generate-config manual.manpages ]'
$ sudo mkdir /etc/nixos
$ sudo `which nixos-generate-config`
… edit the configuration files in /etc/nixos using man configuration.nix
if needed
maybe add: users.extraUsers.root.initialHashedPassword = "" ?
… Build the entire NixOS system and link it to the system profile:
$ nix-env -p /nix/var/nix/profiles/system -f '<nixpkgs/nixos>' -A system --set
… If you were using a single user install:
$ sudo chown -R 0.0 /nix
… NixOS is about to take over
$ sudo touch /etc/NIXOS
$ sudo touch /etc/NIXOS_LUSTRATE
… Let's keep the configuration files we just created
$ echo etc/nixos | sudo tee -a /etc/NIXOS_LUSTRATE
$ sudo mv -v /boot /boot.bak &&
sudo /nix/var/nix/profiles/system/bin/switch-to-configuration boot
$ sudo reboot
… NixOS boots, Stage 1 moves all the old distro stuff in /old-root.
The builder has this convoluted `while` loop which just replicates
`readlink -e`. I'm sure there was a reason at one point, because the
loop has been there since time immemorial. It kept getting copied
around, I suspect because nobody bothered to understand what it actually
did.
Incidentally, this fixes #17513, but I have no idea why.
This patch adds handling of a directory becoming a symlink in
/etc. Before this patch, the directory wasn't removed and then
symlinking failed, which caused directory not being updated at all.
The idea for the patch goes to @abbradar at
https://github.com/NixOS/nixpkgs/issues/16978#issuecomment-232921903:
> A heuristic idea for this -- a function `isStatic :: Path -> Bool`:
>
> * if path `/etc/foo` is a file, return True iff it's a symlink to `/etc/static/foo`.
> * if path is a directory, return True iff for all items in it `isStatic` is True.
>
> On any conflicts, if old path is static, it's safe to replace and/or
> delete stale. Otherwise make a backup and notify the user via a
> journal entry and console output.
The only difference here -- it will not replace user configs.
This also fixes https://github.com/NixOS/nixpkgs/issues/16978.
We currently only allow upstream's default of "reboot.target" due to the
way the symlinks are initialized. I made this configurable similar to the
default unit.
