7:31 a.m.
On 2/5/21 6:10 PM, Kairui Song wrote:
On Thu, Feb 4, 2021 at 10:02 AM Kairui Song <kasong(a)redhat.com>
wrote:
>
> Currently kdump simply uses dracut and pulls all the required binaries
> from the host directly. This keep things simple as kdump is using same
> binaries and libs from the system of fisrt kernel.
>
> But some binaries, like systemd, is growing too large, which increase
> the memory usage by a lot, and most of its features are never used
> in kdump. So it's more reasonable to use a rebuilt-minimized version.
>
> So for such binaries, introduce a "build root" overlay here. Before
> calling dracut to build initramfs, setup an overlay to let the build
> root override current rootfs, so dracut can just work as usual, but the
> binaries used are from the "build root".
>
> All binaries/libs that need to be rebuild for smaller size can be put in
> the build root.
Oh, I forgot to mention, the custom binaries are suppose to be
provided by other packages and installed in /usr/lib/kdump/buildroot
An example package is `kdump-initrd-systemd`:
https://copr.fedorainfracloud.org/coprs/kasong/kexec-kdump-preview/packag...
Is there any systemd document whch can help us to check
CONFIGURE_OPTS_KDUMP in
https://github.com/ryncsn/kdump-initrd-systemd/blob/master/systemd.spec
Thanks,
Pingfan
It's a smaller recompile and repackaged version of systemd, using
this
package can reduce the memory usage by about 20MB.
> ---
> kexec-tools.spec | 1 +
> mkdumprd | 20 +++++++++++++++++++-
> 2 files changed, 20 insertions(+), 1 deletion(-)
>
> diff --git a/kexec-tools.spec b/kexec-tools.spec
> index 91bc0f3..1a06b62 100644
> --- a/kexec-tools.spec
> +++ b/kexec-tools.spec
> @@ -171,6 +171,7 @@ mkdir -p $RPM_BUILD_ROOT%{_unitdir}
> mkdir -p -m755 $RPM_BUILD_ROOT%{_bindir}
> mkdir -p -m755 $RPM_BUILD_ROOT%{_libdir}
> mkdir -p -m755 $RPM_BUILD_ROOT%{_prefix}/lib/kdump
> +mkdir -p -m755 $RPM_BUILD_ROOT%{_prefix}/lib/kdump/buildroot
> install -m 755 %{SOURCE1} $RPM_BUILD_ROOT%{_bindir}/kdumpctl
>
> install -m 755 build/sbin/kexec $RPM_BUILD_ROOT/usr/sbin/kexec
> diff --git a/mkdumprd b/mkdumprd
> index c34b79c..5f8d2da 100644
> --- a/mkdumprd
> +++ b/mkdumprd
> @@ -23,6 +23,7 @@ if [ $? -ne 0 ]; then
> exit 1
> fi
>
> +KDUMP_BUILDROOT="/usr/lib/kdump/buildroot"
> conf_file="/etc/kdump.conf"
> SSH_KEY_LOCATION="/root/.ssh/kdump_id_rsa"
> SAVE_PATH=$(get_save_path)
> @@ -33,12 +34,14 @@ dracut_args="--add kdumpbase --quiet --hostonly
--hostonly-cmdline --hostonly-i1
>
> readonly MKDUMPRD_TMPDIR="$(mktemp -d -t mkdumprd.XXXXXX)"
> [ -d "$MKDUMPRD_TMPDIR" ] || perror_exit "dracut: mktemp -p -d -t
dracut.XXXXXX failed."
> +readonly MKDUMPRD_TMPROOT="$MKDUMPRD_TMPDIR/root"
> readonly MKDUMPRD_TMPMNT="$MKDUMPRD_TMPDIR/target"
>
> trap '
> ret=$?;
> is_mounted $MKDUMPRD_TMPMNT && umount -f $MKDUMPRD_TMPMNT;
> [[ -d $MKDUMPRD_TMPDIR ]] && rm --one-file-system -rf --
"$MKDUMPRD_TMPDIR";
> + [[ -d $MKDUMPRD_TMPROOT ]] && rm --one-file-system -rf --
"$MKDUMPRD_TMPROOT";
> exit $ret;
> ' EXIT
>
> @@ -460,7 +463,22 @@ if ! is_fadump_capable; then
> add_dracut_arg "--no-hostonly-default-device"
> fi
>
> -echo "$dracut_args $@" | xargs dracut
> +if [ -n "$(ls -A1 $KDUMP_BUILDROOT | grep -E "etc|usr")" ];
then
> + # Run in a new namespace, so overlay on root is safe
> + # everything is automatically cleaned up upon exit
> + export KDUMP_BUILDROOT
> + export MKDUMPRD_TMPROOT
> + export dracut_args="$dracut_args $@"
> +
> + cp -r /usr/lib/kdump/buildroot $MKDUMPRD_TMPROOT
> + unshare --mount bash -c '
> + for _d in etc usr; do
> + [ -d "$MKDUMPRD_TMPROOT/$_d" ] && mount overlay -t overlay
-o ro,lowerdir=$MKDUMPRD_TMPROOT/$_d:/$_d /$_d;
> + done
> + echo "$dracut_args $@" | xargs -t dracut;'
> +else
> + echo "$dracut_args $@" | xargs -t dracut
> +fi
>
> _rc=$?
> sync
> --
> 2.29.2
>