nixos/release-combined: adds aarch64-linux as supported

[samueldr]

Motivation for this change

This was previously removed in 74c4e30 .

This will allow hydra to build iso and sd images for aarch64-linux, and share a common channel with the x86-based platforms.

Additionally build iso_minimal_new_kernel on aarch64-linus too.

With #51397 merged, the UEFI iso images build for aarch64-linux too.

• short #nixos-dev discussion

Things done

• ✔️ Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • ✔️ NixOS
  • ⬜ macOS
  • ⬜ other Linux distributions
• ✔️ Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• ⬜ Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• ⬜ Tested execution of all binary files (usually in ./result/bin/)
• ⬜ Determined the impact on package closure size (by running nix path-info -S before and after)
• ✔️ Assured whether relevant documentation is up to date
• ✔️ Fits CONTRIBUTING.md.

---

Tested this way:

~/tmp/nixpkgs/nixpkgs $ time nix-instantiate nixos/release-combined.nix --show-trace
warning: dumping very large path (> 256 MiB); this may run out of memory
trace: Default desktop manager (gnome-xorg) not found at evaluation time.
These are the known valid session names:
  services.xserver.desktopManager.default = "xterm";
  services.xserver.desktopManager.default = "none";
It's also possible the default can be found in one of these packages:
  gnome-session-3.30.1

warning: you did not specify '--add-root'; the result might be removed by the garbage collector
/nix/store/nyii59byg1fs2isl3vbhxdhf88vz96g9-nixos-19.03pre56789.gfedcba.drv

 → exit status: 0
 → user: 439.03, system: 17.78, elapsed: 6:19.25
 → cpu: 120%, max mem: 12231108, avg mem: 0, unshared: 0
 → I/O: <I:0 O:0>, sock: <r:0 s:0>

The trace seen here is also present on the branch this is based-off from. The time it took, though, was 4:33.09.

---

cc @edolstra

[grahamc]

cc @vielmetti

[samueldr]

I'm not entirely pleased with the use of except everywhere.

First, there is the gnome3 test, which already is described as x86_64-linux elsewhere. Not sure if anything can be done while still keeping the list strict.

Then, there are some tests that are not "anything except aarch64-linux", but better described as "only i686-linux and x86_64-linux". For the latter case, adding something like x86LegacyBootable = [ "i686-linux" "x86_64-linux" ]; and a function only which would lib.intersectLists its parameter with the supported platforms may be an good solution. It would document the platforms better like (only x86LegacyBootable nixos.tests.boot.biosCdrom)

[grahamc]

:/ bummer to see all these excepted. What's the scoop?

[samueldr]

This is done so to fast-track this PR, while keeping the channel advancing, while working on making them work.

Right now the issue is that the trace stops at the map function, and I need to dig to see what's the issue. (Except for bios* tests which obviously won't work.) Here's using all nixos.tests.boot.uefiUsb.

~/tmp/nixpkgs/nixpkgs $ time nix-instantiate nixos/release-combined.nix --show-trace
warning: dumping very large path (> 256 MiB); this may run out of memory
error: while evaluating 'hydraJob' at /Users/samuel/tmp/nixpkgs/nixpkgs/lib/customisation.nix:157:14, called from /Users/samuel/tmp/nixpkgs/nixpkgs/nixos/release-combined.nix:41:12:
while evaluating the attribute 'drvPath' at /Users/samuel/tmp/nixpkgs/nixpkgs/lib/customisation.nix:174:13:
while evaluating the attribute 'drvPath' at /Users/samuel/tmp/nixpkgs/nixpkgs/lib/customisation.nix:141:13:
while evaluating the attribute 'constituents' of the derivation 'nixos-19.03pre56789.gfedcba' at /Users/samuel/tmp/nixpkgs/nixpkgs/pkgs/stdenv/generic/make-derivation.nix:185:11:
while evaluating anonymous function at /Users/samuel/tmp/nixpkgs/nixpkgs/nixos/release-combined.nix:50:35, called from undefined position:
attribute 'aarch64-linux' missing, at /Users/samuel/tmp/nixpkgs/nixpkgs/nixos/release-combined.nix:50:43
Command exited with non-zero status 1

I think (hope) that all of the installer and boot tests that could work on aarch64 are currently failing on a common issue. They all fail with what looks like the same error "attribute 'aarch64-linux' missing", which could realistically be from a common cause.

[grahamc]

I wonder if this can be extended to aarch64

[samueldr]

Though this is already documented here why it fails.

# libsmbios is unsupported on aarch64

[grahamc]

I mean the aarch64 + zfs test :)

[samueldr]

~/tmp/nixpkgs/nixpkgs 130 $ time nix-instantiate nixos/release-combined.nix
warning: dumping very large path (> 256 MiB); this may run out of memory
error: Non-EFI boot methods are only supported on i686 / x86_64
(use '--show-trace' to show detailed location information)
Command exited with non-zero status 1

This would be part of the work needed.

[grahamc]

LGTM. It'd be maybe good to add a comment indicating we'd like to extend those test blocks to include aarch64, but not sure it is specifically needed.

[samueldr]

This "broke" eval. Or more rightly so: this strained eval to its tipping point.

Using time and TIME set as such:

TIME=\n → exit status: %x\n → user: %U, system: %S, elapsed: %E\n → cpu: %P, max mem: %M, avg mem: %t, unshared: %D\n → I/O: <I:%I O:%O>, sock: <r:%r s:%s>

With this PR applied:

time nix-instantiate nixos/release-combined.nix --show-trace
 → exit status: 0
 → user: 462.59, system: 18.94, elapsed: 6:59.52
 → cpu: 114%, max mem: 11461328, avg mem: 0, unshared: 0
 → I/O: <I:0 O:0>, sock: <r:0 s:0>

mem is supposed to be in KiBs, so about 10.93 GiB required

Contrast this to before this PR was applied

time nix-instantiate nixos/release-combined.nix --show-trace
 → exit status: 0
 → user: 281.35, system: 13.88, elapsed: 4:32.57
 → cpu: 108%, max mem: 8727624, avg mem: 0, unshared: 0
 → I/O: <I:0 O:0>, sock: <r:0 s:0>

Where it took GiB 8.32

---

The course of action for backtracking this PR, if no other solution can be implemented quickly:

diff --git a/nixos/release-combined.nix b/nixos/release-combined.nix
index 429afe2b145..00750a6f20e 100644
--- a/nixos/release-combined.nix
+++ b/nixos/release-combined.nix
@@ -4,8 +4,8 @@
 
 { nixpkgs ? { outPath = (import ../lib).cleanSource ./..; revCount = 56789; shortRev = "gfedcba"; }
 , stableBranch ? false
-, supportedSystems ? [ "x86_64-linux" "aarch64-linux" ]
-, limitedSupportedSystems ? [ "i686-linux" ]
+, supportedSystems ? [ "x86_64-linux" ]
+, limitedSupportedSystems ? [ "i686-linux" "aarch64-linux" ]
 }:
 
 let

This will allow release-combined.nix to happen, still, for aarch64-linux, but won't use it for tested. That is true since I forgot to add the iso images for aarch64-linux and sd image to the tested set. (Something I'll need to fix anyway.)