(1) explain early kdump a little clearer in "Introduction"
(2) move the notes out to a new "Notes" section for readability and
add a note about need of reconfiguration after kernel update
(3) change journalctl -x option to -b option because -x is unnecessary
and -b will make it very faster if persistent journal is available
(4) shorten the example messages for readability
(5) add a note to "Limitation" about the earliness of early kdump
Signed-off-by: Kazuhito Hagio <k-hagio-ab@nec.com>
Acked-by: Lianbo Jiang <lijiang@redhat.com>
For step2 in early-kdump-howto.txt, --force option of dracut
is necessary to rebuild system initramfs. Without --force option,
executing step2 fails because system initramfs already exists.
Signed-off-by: Shigeki Morishima <s.morishima@jp.fujitsu.com>
Acked-by: Kairui Song <kasong@redhat.com>
Early kdump inherits the settings of normal kdump, so any changes that
caused normal kdump rebuilding also require rebuilding the system initramfs
to make sure that the changes take effect for early kdump.
Therefore, when the early kdump is enabled, provide a prompt message after
the rebuilding of kdump initramfs is completed.
Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Since early kdump is generally used for capturing vmcore when
boot-time panic occurs, if a system always reboots after capturing
vmcore, it can go into a crash loop.
To avoid this issue, this patch add a note of 'final_action' option
to the early kdump document.
Signed-off-by: Kazuhito Hagio <k-hagio@ab.jp.nec.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Lianbo Jiang <lijiang@redhat.com>
Acked-by: Bhupesh Sharma <bhsharma@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Kairui Song <kasong@redhat.com>
Kdump service starts too late, so early crashes will have no chance
to get kdump kernel booting, this will cause crash information to be
lost. It is necessary to add a dracut module in order to load crash
kernel and initramfs as early as possible. You can provide "rd.early
kdump" in grub commandline to enable, then the early kdump will load
those files like the normal kdump, which is disabled by default.
For the normal kdump service, it can check whether the early kdump
has loaded the crash kernel and initramfs. It has no conflict with
the early kdump.
If you rebuild the new initramfs for early kdump, the new initramfs
size will become large, because it will put the vmlinuz and kdump
initramfs into the new initramfs.
In addition, early kdump doesn't support fadump.
Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
Reviewed-by: Kazuhito Hagio <khagio@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
