In reply to @arianvp:matrix.org

I just realized that systemd does some wacky stuff where stage-2 systemd binary inherits state from the stage-1 systemd binary. E.g. to show stage-1 boot times in systemd-analyze blame

I think this currently doesn't work in Nixos as our stage 2 is a shell script execing into systemd instead of systemd that also calls a shellscript

In reply to @arianvp:matrix.org
This might also be something we want to change. Have the first executable in stage-2 be systemd proper

also ElvishJerricco I found this to improve things because I can set env vars:

diff --git a/nixos/lib/systemd-lib.nix b/nixos/lib/systemd-lib.nix
index 3129fbe7bdb..716128a49ac 100644
--- a/nixos/lib/systemd-lib.nix
+++ b/nixos/lib/systemd-lib.nix
@@ -396,6 +396,13 @@ in rec {
       text = commonUnitText def +
         ''
           [Service]
+          ${let env = cfg.globalEnvironment // def.environment;
+            in concatMapStrings (n:
+              let s = optionalString (env.${n} != null)
+                "Environment=${builtins.toJSON "${n}=${env.${n}}"}\n";
+              # systemd max line length is now 1MiB
+              # https://github.com/systemd/systemd/commit/e6dde451a51dc5aaa7f4d98d39b8fe735f73d2af
+              in if stringLength s >= 1048576 then throw "The value of the environment variable ‘${n}’ in systemd service ‘${name}.service’ is too long." else s) (attrNames env)}
           ${attrsToSection def.serviceConfig}
         '';
     };

In reply to @janne.hess:helsinki-systems.de
(on top of your PR). I wonder if we should use cfg.globalEnvironment here. It sets LOCALE_ARCHIVE and TZDIR

In reply to @janne.hess:helsinki-systems.de
(on top of your PR). I wonder if we should use cfg.globalEnvironment here. It sets LOCALE_ARCHIVE and TZDIR

In reply to @arianvp:matrix.org
This might also be something we want to change. Have the first executable in stage-2 be systemd proper

In reply to @bobvanderlinden_:matrix.org
I do think it might help to have an executable like make-initramfs-ng/find-dependencies that doesn't copy everything first to a root dir and afterwards package those files up using cpio. A slight optimization, but I think that can be a separate PR with a separate discission. I won't mention it in the PR to avoid nitty-gritty discussions.

In reply to @elvishjerricco:matrix.org
Janne Heß: Is there a reason boot.initrd.systemd.services.emergency.environtment doesn't work on its own though?

Yeah you are missing:

diff --git a/nixos/lib/systemd-lib.nix b/nixos/lib/systemd-lib.nix
index 3129fbe7bdb..716128a49ac 100644
--- a/nixos/lib/systemd-lib.nix
+++ b/nixos/lib/systemd-lib.nix
@@ -396,6 +396,13 @@ in rec {
       text = commonUnitText def +
         ''
           [Service]
+          ${let env = cfg.globalEnvironment // def.environment;
+            in concatMapStrings (n:
+              let s = optionalString (env.${n} != null)
+                "Environment=${builtins.toJSON "${n}=${env.${n}}"}\n";
+              # systemd max line length is now 1MiB
+              # https://github.com/systemd/systemd/commit/e6dde451a51dc5aaa7f4d98d39b8fe735f73d2af
+              in if stringLength s >= 1048576 then throw "The value of the environment variable ‘${n}’ in systemd service ‘${name}.service’ is too long." else s) (attrNames env)}
           ${attrsToSection def.serviceConfig}
         '';
     };

I think that's a good point. I'd like to make that change but just didn't bother last night. I wouldn't be opposed to a patch to change that in this PR

ElvishJerricco no worries. I was thinking these kinds of optimizations can also happen after the PR. I'd rather be in a state where the PR is merged and multiple people can create PRs to improve the various parts of initrd-systemd, rather than everyone commenting/attempting to make changes to the PR itself, leaving you to be the central person that needs to do things: a situation I'd like to avoid with the time it takes for some PRs