diff --git a/api-daemon/provisioner/examples/debootstrap_script.py b/api-daemon/provisioner/examples/debootstrap_script.py index ed569d92..c554ce5e 100644 --- a/api-daemon/provisioner/examples/debootstrap_script.py +++ b/api-daemon/provisioner/examples/debootstrap_script.py @@ -34,6 +34,29 @@ # with that. import os +from contextlib import contextmanager + + +# Create a chroot context manager +# This can be used later in the script to chroot to the destination directory +# for instance to run commands within the target. +@contextmanager +def chroot_target(destination): + try: + real_root = os.open("/", os.O_RDONLY) + os.chroot(destination) + fake_root = os.open("/", os.O_RDONLY) + os.fchdir(fake_root) + yield + finally: + os.fchdir(real_root) + os.chroot(".") + os.fchdir(real_root) + os.close(fake_root) + os.close(real_root) + del fake_root + del real_root + # Installation function - performs a debootstrap install of a Debian system # Note that the only arguments are keyword arguments. @@ -193,40 +216,25 @@ GRUB_DISABLE_LINUX_UUID=false fh.write(data) # Chroot, do some in-root tasks, then exit the chroot - # EXITING THE CHROOT IS VERY IMPORTANT OR THE FOLLOWING STAGES OF THE PROVISIONER - # WILL FAIL IN UNEXPECTED WAYS! Keep this in mind when using chroot in your scripts. - real_root = os.open("/", os.O_RDONLY) - os.chroot(temporary_directory) - fake_root = os.open("/", os.O_RDONLY) - os.fchdir(fake_root) - - # Install and update GRUB - os.system( - "grub-install --force /dev/rbd/{}/{}_{}".format(root_disk['pool'], vm_name, root_disk['disk_id']) - ) - os.system( - "update-grub" - ) - # Set a really dumb root password [TEMPORARY] - os.system( - "echo root:test123 | chpasswd" - ) - # Enable cloud-init target on (first) boot - # NOTE: Your user-data should handle this and disable it once done, or things get messy. - # That cloud-init won't run without this hack seems like a bug... but even the official - # Debian cloud images are affected, so who knows. - os.system( - "systemctl enable cloud-init.target" - ) - - # Restore our original root/exit the chroot - # EXITING THE CHROOT IS VERY IMPORTANT OR THE FOLLOWING STAGES OF THE PROVISIONER - # WILL FAIL IN UNEXPECTED WAYS! Keep this in mind when using chroot in your scripts. - os.fchdir(real_root) - os.chroot(".") - os.fchdir(real_root) - os.close(fake_root) - os.close(real_root) + with chroot_target(temporary_directory): + # Install and update GRUB + os.system( + "grub-install --force /dev/rbd/{}/{}_{}".format(root_disk['pool'], vm_name, root_disk['disk_id']) + ) + os.system( + "update-grub" + ) + # Set a really dumb root password [TEMPORARY] + os.system( + "echo root:test123 | chpasswd" + ) + # Enable cloud-init target on (first) boot + # NOTE: Your user-data should handle this and disable it once done, or things get messy. + # That cloud-init won't run without this hack seems like a bug... but even the official + # Debian cloud images are affected, so who knows. + os.system( + "systemctl enable cloud-init.target" + ) # Unmount the bound devfs os.system( @@ -235,8 +243,4 @@ GRUB_DISABLE_LINUX_UUID=false ) ) - # Clean up file handles so paths can be unmounted - del fake_root - del real_root - # Everything else is done via cloud-init user-data diff --git a/api-daemon/provisioner/examples/dummy_script.py b/api-daemon/provisioner/examples/dummy_script.py index 216b5a04..bb7bebb9 100644 --- a/api-daemon/provisioner/examples/dummy_script.py +++ b/api-daemon/provisioner/examples/dummy_script.py @@ -29,7 +29,7 @@ # This script will run under root privileges as the provisioner does. Be careful # with that. -# Installation function - performs a debootstrap install of a Debian system +# Installation function - performs no actions then returns # Note that the only arguments are keyword arguments. def install(**kwargs): # The provisioner has already mounted the disks on kwargs['temporary_directory'].