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Fix fedora-minimal kernel-install on older platforms

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fedora-minimal fails to build on Ubuntu Trusty due do being unable to
find the initrd (see Id4c04d7ae20068643df34d2fa31068e8a917a52d).

This is a rather obscure problem that comes from the intersection of
several things.

The first thing to note is that the post-install scripts of the
kernel-core package use kernel-install [1].  For whatever reason, this
installs the kernel to /boot/MACHINE-ID/KERNEL-VERSION

MACHINE-ID comes from /etc/machine-id; a UUID that should have been
created by the systemd post-inst scripts with systemd-machine-id-setup
[2].

The chroot environment provided for root.d elements has no kernel
file-systems like /proc or /dev mounted.  This is where differences in
the base-system come into play -- on more recent systems that
implement getrandom() systemd does not need /dev/urandom to generate
the machine-id [3]; we get a value and /etc/machine-id is populated.

On older platforms (Trusty), systemd-machine-id-setup fails (unable to
access /dev/urandom) and we end up with a blank /etc/machine-id.  This
ends up making kernel-install (the script) fail during yum's
installation of kernel-core, which means the initrd is not installed
correctly.

We end up bailing out in fedora-minimal/install.d/99-ramdisk, where we
try to put the installed ramdisk in /boot for the later grub install
scripts to find.

The solution here is to mount the standard kernel file-systems within
the chroot before we try installing.

[1] http://www.freedesktop.org/software/systemd/man/kernel-install.html
[2] http://www.freedesktop.org/software/systemd/man/systemd-machine-id-setup.html
[3] https://github.com/systemd/systemd/blob/master/src/basic/random-util.c

Change-Id: Ibcce35da928f64e6a719b070bcc833346ee7ee92
This commit is contained in:
Ian Wienand 2015-10-27 15:10:30 +11:00
parent a67ee17d62
commit f307bb4d8b
1 changed files with 16 additions and 0 deletions
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16
elements/yum-minimal/root.d/08-yum-chroot
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@ -97,6 +97,16 @@ if [ -n "$DIB_OFFLINE" -o -n "${DIB_YUMCHROOT_USE_CACHE:-}" ] && [ -f $YUMCHROOT
echo $YUMCHROOT_TARBALL found in cache. Using.
sudo tar -C $TARGET_ROOT --numeric-owner -xzf $YUMCHROOT_TARBALL
else
# Note this is not usually done for root.d elements (see
# lib/common-functions:mount_proc_dev_sys) but it's important that
# we have things like /dev/urandom around inside the chroot for
# the rpm [pre|post]inst scripts within the packages.
sudo mkdir -p $TARGET_ROOT/proc $TARGET_ROOT/dev $TARGET_ROOT/sys
sudo mount -t proc none $TARGET_ROOT/proc
sudo mount --bind /dev $TARGET_ROOT/dev
sudo mount --bind /dev/pts $TARGET_ROOT/dev/pts
sudo mount -t sysfs none $TARGET_ROOT/sys
# initalize rpmdb
sudo mkdir -p $TARGET_ROOT/var/lib/rpm
sudo rpm --root $TARGET_ROOT --initdb
@ -128,8 +138,14 @@ else
install passwd findutils sudo util-linux-ng
# cleanup
# TODO : move this into a exit trap; and reconsider how
# this integrates with the global exit cleanup path.
sudo rm $TARGET_ROOT/etc/resolv.conf
sudo umount $TMP_MOUNT_PATH/tmp/yum
sudo umount $TARGET_ROOT/proc
sudo umount $TARGET_ROOT/dev/pts
sudo umount $TARGET_ROOT/dev
sudo umount $TARGET_ROOT/sys
# RPM doesn't know whether files have been changed since install
# At this point though, we know for certain that we have changed no