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qemu-vm: Use unionfs-fuse instead of aufs for writableStore

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This commit is contained in:
Shea Levy 2012-12-16 11:56:49 -05:00
parent be4f69519b
commit 3eb0faf317
1 changed files with 18 additions and 8 deletions
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26
modules/virtualisation/qemu-vm.nix
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@ -95,7 +95,7 @@ let
description =
''
If enabled, the Nix store in the VM is made writable by
layering an AUFS/tmpfs filesystem on top of the host's Nix
layering a unionfs-fuse/tmpfs filesystem on top of the host's Nix
store.
'';
};
@ -250,16 +250,18 @@ in
# CIFS. Also use paravirtualised network and block devices for
# performance.
boot.initrd.availableKernelModules =
[ "cifs" "nls_utf8" "hmac" "md4" "ecb" "des_generic" ]
++ optional cfg.writableStore [ "aufs" ];
[ "cifs" "nls_utf8" "hmac" "md4" "ecb" "des_generic" ];
boot.extraModulePackages =
optional cfg.writableStore config.boot.kernelPackages.aufs;
# unionfs-fuse expects fuse to be loaded
boot.initrd.kernelModules = optional cfg.writableStore [ "fuse" ];
boot.initrd.extraUtilsCommands =
''
# We need mke2fs in the initrd.
cp ${pkgs.e2fsprogs}/sbin/mke2fs $out/bin
'' + optionalString cfg.writableStore ''
cp -v ${pkgs.fuse}/lib/libfuse* $out/lib
cp -v ${pkgs.unionfs-fuse}/bin/unionfs $out/bin
'';
boot.initrd.postDeviceCommands =
@ -288,9 +290,17 @@ in
mkdir -p $targetRoot/boot
mount -o remount,ro $targetRoot/nix/store
${optionalString cfg.writableStore ''
mkdir /mnt-store-tmpfs
mount -t tmpfs -o "mode=755" none /mnt-store-tmpfs
mount -t aufs -o dirs=/mnt-store-tmpfs=rw:$targetRoot/nix/store=rr none $targetRoot/nix/store
# Hacky!!! fuse hard-codes the path to mount
mkdir -p /nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-${pkgs.utillinux.name}/bin
ln -s $(which mount) /nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-${pkgs.utillinux.name}/bin
ln -s $(which umount) /nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-${pkgs.utillinux.name}/bin
mkdir -p /unionfs-chroot$targetRoot
mount --rbind $targetRoot /unionfs-chroot$targetRoot
mkdir /unionfs-chroot/mnt-store-tmpfs
mount -t tmpfs -o "mode=755" none /unionfs-chroot/mnt-store-tmpfs
unionfs -o allow_other,cow,nonempty,chroot=/unionfs-chroot /mnt-store-tmpfs=RW:$targetRoot/nix/store=RO $targetRoot/nix/store
''}
'';