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nixos/boot-media: soft-force entire fs layout

https://github.com/NixOS/nixpkgs/pull/131760 was made to avo
a speicific configuration conflict that errored out for multiple definitions of "/" when the installer where overlayed
on any existing host configuration.

---

Problem 1: It turns out that in also other mountpoints can coflict.

Solution 1: use `mkOverride 60` for all mountpoints (even for the ones unlikely causing confilct for consistency sake)

---

Problem 2: It turns out that on an installation media for a fresh machine (before formatting), we usually don't have any devices yet formatted. However defining for example `fileSystems.<nme>.device = "/dev/disk/by-label/...", in newer versions of nixos, seems to make the system startup fail. Similarily waiting for a non-existent swap device does not make the startup fail, but has a 1:30 min timeout.

Solution 2: For an installation medium, soft-override ("unless users know what they are doing") the entire `fileSystems` and `swapDevices` definitions.

David Arnold 2af2d314 8ff76e34

options
unified split
Changed files
+68 -57
nixos
modules
installer
cd-dvd
installation-cd-base.nix
iso-image.nix
netboot
netboot.nix
+6
nixos/modules/installer/cd-dvd/installation-cd-base.nix 
···

       
30

       
 

       
  # Add Memtest86+ to the CD.


     

       
31

       
 

       
  boot.loader.grub.memtest86.enable = true;


     

       
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33

       
 

       
  boot.postBootCommands = ''


     

       
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    for o in $(</proc/cmdline); do


     

       
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      case "$o" in


     
···

       
30

       
 

       
  # Add Memtest86+ to the CD.


     

       
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  boot.loader.grub.memtest86.enable = true;


     

       
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33

       
+

       
  # On a fresh machine, before formatting, an installation


     

       
34

       
+

       
  # media cannot assume an existing file system layout such


     

       
35

       
+

       
  # as might be defined by the encapsulated host config.


     

       
36

       
+

       
  swapDevices = mkOverride 60 [ ];


     

       
37

       
+

       
  fileSystems = mkOverride 60 config.lib.isoFileSystems;


     

       
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+

       



     

       
39

       
 

       
  boot.postBootCommands = ''


     

       
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    for o in $(</proc/cmdline); do


     

       
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      case "$o" in
+53 -48
nixos/modules/installer/cd-dvd/iso-image.nix 
···

       
614

       
 

       
    };


     

       
615

       
 

       



     

       
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  };


     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       
617

       
 

       



     

       
618

       
 

       
  config = {


     

       
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    assertions = [


     
···

       
653

       
 

       
        "boot.shell_on_fail"


     

       
654

       
 

       
      ];


     

       
655

       
 

       



     

       
656

       
-

       
    fileSystems."/" =


     

       
657

       
-

       
      # This module is often over-layed onto an existing host config


     

       
658

       
-

       
      # that defines `/`. We use mkOverride 60 to override standard


     

       
659

       
-

       
      # values, but at the same time leave room for mkForce values


     

       
660

       
-

       
      # targeted at the image build.


     

       
661

       
-

       
      { fsType = mkOverride 60 "tmpfs";


     

       
662

       
-

       
        options = [ "mode=0755" ];


     

       
663

       
-

       
      };


     

       
664

       
-

       



     

       
665

       
-

       
    # Note that /dev/root is a symlink to the actual root device


     

       
666

       
-

       
    # specified on the kernel command line, created in the stage 1


     

       
667

       
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    # init script.


     

       
668

       
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    fileSystems."/iso" =


     

       
669

       
-

       
      { device = "/dev/root";


     

       
670

       
-

       
        neededForBoot = true;


     

       
671

       
-

       
        noCheck = true;


     

       
672

       
-

       
      };


     

       
673

       
-

       



     

       
674

       
-

       
    # In stage 1, mount a tmpfs on top of /nix/store (the squashfs


     

       
675

       
-

       
    # image) to make this a live CD.


     

       
676

       
-

       
    fileSystems."/nix/.ro-store" =


     

       
677

       
-

       
      { fsType = "squashfs";


     

       
678

       
-

       
        device = "/iso/nix-store.squashfs";


     

       
679

       
-

       
        options = [ "loop" ];


     

       
680

       
-

       
        neededForBoot = true;


     

       
681

       
-

       
      };


     

       
682

       
-

       



     

       
683

       
-

       
    fileSystems."/nix/.rw-store" =


     

       
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-

       
      { fsType = "tmpfs";


     

       
685

       
-

       
        options = [ "mode=0755" ];


     

       
686

       
-

       
        neededForBoot = true;


     

       
687

       
-

       
      };


     

       
688

       
-

       



     

       
689

       
-

       
    fileSystems."/nix/store" =


     

       
690

       
-

       
      { fsType = "overlay";


     

       
691

       
-

       
        device = "overlay";


     

       
692

       
-

       
        options = [


     

       
693

       
-

       
          "lowerdir=/nix/.ro-store"


     

       
694

       
-

       
          "upperdir=/nix/.rw-store/store"


     

       
695

       
-

       
          "workdir=/nix/.rw-store/work"


     

       
696

       
-

       
        ];


     

       
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-

       



     

       
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-

       
        depends = [


     

       
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-

       
          "/nix/.ro-store"


     

       
700

       
-

       
          "/nix/.rw-store/store"


     

       
701

       
-

       
          "/nix/.rw-store/work"


     

       
702

       
-

       
        ];


     

       
703

       
-

       
      };


     

       
704

       
 

       



     

       
705

       
 

       
    boot.initrd.availableKernelModules = [ "squashfs" "iso9660" "uas" "overlay" ];


     

       
706

       
 

       



     
···

       
614

       
 

       
    };


     

       
615

       
 

       



     

       
616

       
 

       
  };


     

       
617

       
+

       
  # store them in lib so we can set the same fileSystems with a


     

       
618

       
+

       
  # higher prio on installation media


     

       
619

       
+

       
  # This module is often over-layed onto an existing host config


     

       
620

       
+

       
  # that defines `fileSystems`. We use mkOverride 60 to override


     

       
621

       
+

       
  # standard values, but at the same time leave room for mkForce


     

       
622

       
+

       
  # values targeted at the image build.


     

       
623

       
+

       
  config.lib.isoFileSystems = {


     

       
624

       
+

       
    "/" = mkOverride 60


     

       
625

       
+

       
      {


     

       
626

       
+

       
        fsType = "tmpfs";


     

       
627

       
+

       
        options = [ "mode=0755" ];


     

       
628

       
+

       
      };


     

       
629

       
+

       



     

       
630

       
+

       
    # Note that /dev/root is a symlink to the actual root device


     

       
631

       
+

       
    # specified on the kernel command line, created in the stage 1


     

       
632

       
+

       
    # init script.


     

       
633

       
+

       
    "/iso" = mkOverride 60


     

       
634

       
+

       
      { device = "/dev/root";


     

       
635

       
+

       
        neededForBoot = true;


     

       
636

       
+

       
        noCheck = true;


     

       
637

       
+

       
      };


     

       
638

       
+

       



     

       
639

       
+

       
    # In stage 1, mount a tmpfs on top of /nix/store (the squashfs


     

       
640

       
+

       
    # image) to make this a live CD.


     

       
641

       
+

       
    "/nix/.ro-store" = mkOverride 60


     

       
642

       
+

       
      { fsType = "squashfs";


     

       
643

       
+

       
        device = "/iso/nix-store.squashfs";


     

       
644

       
+

       
        options = [ "loop" ];


     

       
645

       
+

       
        neededForBoot = true;


     

       
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+

       
      };


     

       
647

       
+

       



     

       
648

       
+

       
    "/nix/.rw-store" = mkOverride 60


     

       
649

       
+

       
      { fsType = "tmpfs";


     

       
650

       
+

       
        options = [ "mode=0755" ];


     

       
651

       
+

       
        neededForBoot = true;


     

       
652

       
+

       
      };


     

       
653

       
+

       



     

       
654

       
+

       
    "/nix/store" = mkOverride 60


     

       
655

       
+

       
      { fsType = "overlay";


     

       
656

       
+

       
        device = "overlay";


     

       
657

       
+

       
        options = [


     

       
658

       
+

       
          "lowerdir=/nix/.ro-store"


     

       
659

       
+

       
          "upperdir=/nix/.rw-store/store"


     

       
660

       
+

       
          "workdir=/nix/.rw-store/work"


     

       
661

       
+

       
        ];


     

       
662

       
+

       
        depends = [


     

       
663

       
+

       
          "/nix/.ro-store"


     

       
664

       
+

       
          "/nix/.rw-store/store"


     

       
665

       
+

       
          "/nix/.rw-store/work"


     

       
666

       
+

       
        ];


     

       
667

       
+

       
      };


     

       
668

       
+

       
  };


     

       
669

       
 

       



     

       
670

       
 

       
  config = {


     

       
671

       
 

       
    assertions = [


     
···

       
705

       
 

       
        "boot.shell_on_fail"


     

       
706

       
 

       
      ];


     

       
707

       
 

       



     

       
708

       
+

       
    fileSystems = config.lib.isoFileSystems;


     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       

       

       
     

       
709

       
 

       



     

       
710

       
 

       
    boot.initrd.availableKernelModules = [ "squashfs" "iso9660" "uas" "overlay" ];


     

       
711
+9 -9
nixos/modules/installer/netboot/netboot.nix 
···

       
29

       
 

       
          then []


     

       
30

       
 

       
          else [ pkgs.grub2 pkgs.syslinux ]);


     

       
31

       
 

       



     

       
32

       
-

       
    fileSystems."/" =


     

       
33

       
-

       
      # This module is often over-layed onto an existing host config


     

       
34

       
-

       
      # that defines `/`. We use mkOverride 60 to override standard


     

       
35

       
-

       
      # values, but at the same time leave room for mkForce values


     

       
36

       
-

       
      # targeted at the image build.


     

       
37

       
-

       
      { fsType = mkOverride 60 "tmpfs";


     

       
38

       
 

       
        options = [ "mode=0755" ];


     

       
39

       
 

       
      };


     

       
40

       
 

       



     

       
41

       
 

       
    # In stage 1, mount a tmpfs on top of /nix/store (the squashfs


     

       
42

       
 

       
    # image) to make this a live CD.


     

       
43

       
-

       
    fileSystems."/nix/.ro-store" =


     

       
44

       
 

       
      { fsType = "squashfs";


     

       
45

       
 

       
        device = "../nix-store.squashfs";


     

       
46

       
 

       
        options = [ "loop" ];


     

       
47

       
 

       
        neededForBoot = true;


     

       
48

       
 

       
      };


     

       
49

       
 

       



     

       
50

       
-

       
    fileSystems."/nix/.rw-store" =


     

       
51

       
 

       
      { fsType = "tmpfs";


     

       
52

       
 

       
        options = [ "mode=0755" ];


     

       
53

       
 

       
        neededForBoot = true;


     

       
54

       
 

       
      };


     

       
55

       
 

       



     

       
56

       
-

       
    fileSystems."/nix/store" =


     

       
57

       
 

       
      { fsType = "overlay";


     

       
58

       
 

       
        device = "overlay";


     

       
59

       
 

       
        options = [


     
···

       
29

       
 

       
          then []


     

       
30

       
 

       
          else [ pkgs.grub2 pkgs.syslinux ]);


     

       
31

       
 

       



     

       
32

       
+

       
    # This module is often over-layed onto an existing host config


     

       
33

       
+

       
    # that defines `fileSystems`. We use mkOverride 60 to override


     

       
34

       
+

       
    # standard values, but at the same time leave room for mkForce


     

       
35

       
+

       
    # values targeted at the image build.


     

       
36

       
+

       
    fileSystems."/" = mkOverride 60


     

       
37

       
+

       
      { fsType = "tmpfs";


     

       
38

       
 

       
        options = [ "mode=0755" ];


     

       
39

       
 

       
      };


     

       
40

       
 

       



     

       
41

       
 

       
    # In stage 1, mount a tmpfs on top of /nix/store (the squashfs


     

       
42

       
 

       
    # image) to make this a live CD.


     

       
43

       
+

       
    fileSystems."/nix/.ro-store" = mkOverride 60


     

       
44

       
 

       
      { fsType = "squashfs";


     

       
45

       
 

       
        device = "../nix-store.squashfs";


     

       
46

       
 

       
        options = [ "loop" ];


     

       
47

       
 

       
        neededForBoot = true;


     

       
48

       
 

       
      };


     

       
49

       
 

       



     

       
50

       
+

       
    fileSystems."/nix/.rw-store" = mkOverride 60


     

       
51

       
 

       
      { fsType = "tmpfs";


     

       
52

       
 

       
        options = [ "mode=0755" ];


     

       
53

       
 

       
        neededForBoot = true;


     

       
54

       
 

       
      };


     

       
55

       
 

       



     

       
56

       
+

       
    fileSystems."/nix/store" = mkOverride 60


     

       
57

       
 

       
      { fsType = "overlay";


     

       
58

       
 

       
        device = "overlay";


     

       
59

       
 

       
        options = [