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Merge pull request #120489 from samueldr/fix/make-disk-image-auto-size

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Fix make disk image automatic size
This commit is contained in:
Lassulus 2021-04-26 10:34:15 +02:00 committed by GitHub
parent 0e391039ed 7b8b3fab6d
commit ee04d772e4
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GPG key ID: 4AEE18F83AFDEB23
10 changed files with 91 additions and 22 deletions
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75
nixos/lib/make-disk-image.nix
View file

@ -15,6 +15,8 @@
, # size of the boot partition, is only used if partitionTableType is
# either "efi" or "hybrid"
# This will be undersized slightly, as this is actually the offset of
# the end of the partition. Generally it will be 1MiB smaller.
bootSize ? "256M"
, # The files and directories to be placed in the target file system.
@ -163,6 +165,8 @@ let format' = format; in let
closureInfo = pkgs.closureInfo { rootPaths = [ config.system.build.toplevel channelSources ]; };
blockSize = toString (4 * 1024); # ext4fs block size (not block device sector size)
prepareImage = ''
export PATH=${binPath}
@ -175,6 +179,24 @@ let format' = format; in let
echo $(( "$1" * 512 ))
}
# Given lines of numbers, adds them together
sum_lines() {
local acc=0
while read -r number; do
acc=$((acc+number))
done
echo "$acc"
}
mebibyte=$(( 1024 * 1024 ))
# Approximative percentage of reserved space in an ext4 fs over 512MiB.
# 0.05208587646484375
# × 1000, integer part: 52
compute_fudge() {
echo $(( $1 * 52 / 1000 ))
}
mkdir $out
root="$PWD/root"
@ -235,12 +257,53 @@ let format' = format; in let
${if diskSize == "auto" then ''
${if partitionTableType == "efi" || partitionTableType == "hybrid" then ''
additionalSpace=$(( ($(numfmt --from=iec '${additionalSpace}') + $(numfmt --from=iec '${bootSize}')) / 1000 ))
# Add the GPT at the end
gptSpace=$(( 512 * 34 * 1 ))
# Normally we'd need to account for alignment and things, if bootSize
# represented the actual size of the boot partition. But it instead
# represents the offset at which it ends.
# So we know bootSize is the reserved space in front of the partition.
reservedSpace=$(( gptSpace + $(numfmt --from=iec '${bootSize}') ))
'' else if partitionTableType == "legacy+gpt" then ''
# Add the GPT at the end
gptSpace=$(( 512 * 34 * 1 ))
# And include the bios_grub partition; the ext4 partition starts at 2MB exactly.
reservedSpace=$(( gptSpace + 2 * mebibyte ))
'' else if partitionTableType == "legacy" then ''
# Add the 1MiB aligned reserved space (includes MBR)
reservedSpace=$(( mebibyte ))
'' else ''
additionalSpace=$(( $(numfmt --from=iec '${additionalSpace}') / 1000 ))
reservedSpace=0
''}
diskSize=$(( $(set -- $(du -d0 $root); echo "$1") + $additionalSpace ))
truncate -s "$diskSize"K $diskImage
additionalSpace=$(( $(numfmt --from=iec '${additionalSpace}') + reservedSpace ))
# Compute required space in filesystem blocks
diskUsage=$(find . ! -type d -exec 'du' '--apparent-size' '--block-size' "${blockSize}" '{}' ';' | cut -f1 | sum_lines)
# Each inode takes space!
numInodes=$(find . | wc -l)
# Convert to bytes, inodes take two blocks each!
diskUsage=$(( (diskUsage + 2 * numInodes) * ${blockSize} ))
# Then increase the required space to account for the reserved blocks.
fudge=$(compute_fudge $diskUsage)
requiredFilesystemSpace=$(( diskUsage + fudge ))
diskSize=$(( requiredFilesystemSpace + additionalSpace ))
# Round up to the nearest mebibyte.
# This ensures whole 512 bytes sector sizes in the disk image
# and helps towards aligning partitions optimally.
if (( diskSize % mebibyte )); then
diskSize=$(( ( diskSize / mebibyte + 1) * mebibyte ))
fi
truncate -s "$diskSize" $diskImage
printf "Automatic disk size...\n"
printf " Closure space use: %d bytes\n" $diskUsage
printf " fudge: %d bytes\n" $fudge
printf " Filesystem size needed: %d bytes\n" $requiredFilesystemSpace
printf " Additional space: %d bytes\n" $additionalSpace
printf " Disk image size: %d bytes\n" $diskSize
'' else ''
truncate -s ${toString diskSize}M $diskImage
''}
@ -251,9 +314,9 @@ let format' = format; in let
# Get start & length of the root partition in sectors to $START and $SECTORS.
eval $(partx $diskImage -o START,SECTORS --nr ${rootPartition} --pairs)
mkfs.${fsType} -F -L ${label} $diskImage -E offset=$(sectorsToBytes $START) $(sectorsToKilobytes $SECTORS)K
mkfs.${fsType} -b ${blockSize} -F -L ${label} $diskImage -E offset=$(sectorsToBytes $START) $(sectorsToKilobytes $SECTORS)K
'' else ''
mkfs.${fsType} -F -L ${label} $diskImage
mkfs.${fsType} -b ${blockSize} -F -L ${label} $diskImage
''}
echo "copying staging root to image..."

1
nixos/maintainers/scripts/cloudstack/cloudstack-image.nix
View file

@ -10,7 +10,6 @@ with lib;
system.build.cloudstackImage = import ../../../lib/make-disk-image.nix {
inherit lib config pkgs;
diskSize = 8192;
format = "qcow2";
configFile = pkgs.writeText "configuration.nix"
''

5
nixos/maintainers/scripts/ec2/amazon-image.nix
View file

@ -40,8 +40,9 @@ in {
};
sizeMB = mkOption {
type = types.int;
default = if config.ec2.hvm then 2048 else 8192;
type = with types; either (enum [ "auto" ]) int;
default = "auto";
example = 8192;
description = "The size in MB of the image";
};

2
nixos/maintainers/scripts/openstack/openstack-image.nix
View file

@ -12,8 +12,8 @@ with lib;
system.build.openstackImage = import ../../../lib/make-disk-image.nix {
inherit lib config;
additionalSpace = "1024M";
pkgs = import ../../../.. { inherit (pkgs) system; }; # ensure we use the regular qemu-kvm package
diskSize = 8192;
format = "qcow2";
configFile = pkgs.writeText "configuration.nix"
''

5
nixos/modules/virtualisation/azure-image.nix
View file

@ -9,8 +9,9 @@ in
options = {
virtualisation.azureImage.diskSize = mkOption {
type = with types; int;
default = 2048;
type = with types; either (enum [ "auto" ]) int;
default = "auto";
example = 2048;
description = ''
Size of disk image. Unit is MB.
'';

5
nixos/modules/virtualisation/digital-ocean-image.nix
View file

@ -10,8 +10,9 @@ in
options = {
virtualisation.digitalOceanImage.diskSize = mkOption {
type = with types; int;
default = 4096;
type = with types; either (enum [ "auto" ]) int;
default = "auto";
example = 4096;
description = ''
Size of disk image. Unit is MB.
'';

5
nixos/modules/virtualisation/google-compute-image.nix
View file

@ -18,8 +18,9 @@ in
options = {
virtualisation.googleComputeImage.diskSize = mkOption {
type = with types; int;
default = 1536;
type = with types; either (enum [ "auto" ]) int;
default = "auto";
example = 1536;
description = ''
Size of disk image. Unit is MB.
'';

5
nixos/modules/virtualisation/hyperv-image.nix
View file

@ -9,8 +9,9 @@ in {
options = {
hyperv = {
baseImageSize = mkOption {
type = types.int;
default = 2048;
type = with types; either (enum [ "auto" ]) int;
default = "auto";
example = 2048;
description = ''
The size of the hyper-v base image in MiB.
'';

5
nixos/modules/virtualisation/virtualbox-image.nix
View file

@ -11,8 +11,9 @@ in {
options = {
virtualbox = {
baseImageSize = mkOption {
type = types.int;
default = 50 * 1024;
type = with types; either (enum [ "auto" ]) int;
default = "auto";
example = 50 * 1024;
description = ''
The size of the VirtualBox base image in MiB.
'';

5
nixos/modules/virtualisation/vmware-image.nix
View file

@ -18,8 +18,9 @@ in {
options = {
vmware = {
baseImageSize = mkOption {
type = types.int;
default = 2048;
type = with types; either (enum [ "auto" ]) int;
default = "auto";
example = 2048;
description = ''
The size of the VMWare base image in MiB.
'';