nixosTests.installer: Fix grub1 test being unreliable

The kernel sometimes assigns `/dev/sdb` to the 8GiB disk. This, in turn,
means the test will fail because we're targeting the wrong disk.

```
machine # [    0.000000] sd 2:0:0:0: [sda] 16777216 512-byte logical blocks: (8.59 GB/8.00 GiB)
machine # [    0.000000] sd 3:0:0:0: [sdb] 1048576 512-byte logical blocks: (537 MB/512 MiB)
```

```
machine # [    0.000000] sd 2:0:0:0: [sdb] 16777216 512-byte logical blocks: (8.59 GB/8.00 GiB)
machine # [    0.000000] sd 3:0:0:0: [sda] 1048576 512-byte logical blocks: (537 MB/512 MiB)
```

Note how the "sd x:0:0:0:` ID is stable. That is because QEMU **is**
told to give specific identifiers to the disks. So using the
dev/disk/by-id/ identifiers is stable.

* * *

Tested by forcing the sda/sdb swap this way:

    diff --git a/nixos/tests/installer.nix b/nixos/tests/installer.nix
    index 24c55081f9a..2eee224351b 100644
    --- a/nixos/tests/installer.nix
    +++ b/nixos/tests/installer.nix
    @@ -702,12 +702,19 @@ in {
               + " mkpart primary linux-swap 1M 1024M"
               + " mkpart primary ext2 1024M -1s",
               "udevadm settle",
    +      )
    +      print(machine.succeed("find /dev/disk/ '!' -type d -printf '%p → %l\n' | sort"))
    +      machine.succeed(
               "mkswap ${grubDevice}-part1 -L swap",
               "swapon -L swap",
               "mkfs.ext3 -L nixos ${grubDevice}-part2",
               "mount LABEL=nixos /mnt",
               "mkdir -p /mnt/tmp",
           )
    +      machine.succeed("echo success")
    +      machine.succeed(
    +          'if [[ "$(find ${grubDevice} -printf \'%l\')" != "../../sdb" ]]; then exit 22; else true; fi'
    +      )
         '';
         grubVersion = 1;
         # /dev/sda is not stable, even when the SCSI disk number is.

And ran this way:

     $ until (clear; tmux clear ; time env -i nix-build nixos/release-combined.nix -A nixos.tests.installer.grub1.x86_64-linux); do echo derp; done
This commit is contained in:
Samuel Dionne-Riel 2021-04-25 19:37:19 -04:00
parent 93de027ee0
commit 7d112134de

View file

@ -294,7 +294,7 @@ let
# the same during and after installation.
virtualisation.emptyDiskImages = [ 512 ];
virtualisation.bootDevice =
if grubVersion == 1 then "/dev/sdb" else "/dev/vdb";
if grubVersion == 1 then "/dev/disk/by-id/scsi-0QEMU_QEMU_HARDDISK_drive2" else "/dev/vdb";
virtualisation.qemu.diskInterface =
if grubVersion == 1 then "scsi" else "virtio";
@ -695,22 +695,23 @@ in {
};
# Test a basic install using GRUB 1.
grub1 = makeInstallerTest "grub1" {
grub1 = makeInstallerTest "grub1" rec {
createPartitions = ''
machine.succeed(
"flock /dev/sda parted --script /dev/sda -- mklabel msdos"
"flock ${grubDevice} parted --script ${grubDevice} -- mklabel msdos"
+ " mkpart primary linux-swap 1M 1024M"
+ " mkpart primary ext2 1024M -1s",
"udevadm settle",
"mkswap /dev/sda1 -L swap",
"mkswap ${grubDevice}-part1 -L swap",
"swapon -L swap",
"mkfs.ext3 -L nixos /dev/sda2",
"mkfs.ext3 -L nixos ${grubDevice}-part2",
"mount LABEL=nixos /mnt",
"mkdir -p /mnt/tmp",
)
'';
grubVersion = 1;
grubDevice = "/dev/sda";
# /dev/sda is not stable, even when the SCSI disk number is.
grubDevice = "/dev/disk/by-id/scsi-0QEMU_QEMU_HARDDISK_drive1";
};
# Test using labels to identify volumes in grub