When using multipath devices as the target for kdump, if user_friendly_name
is also specified, devices default to names like "mpath*", e.g., mpatha.
In dracut, we obtain a persistent device name via get_persistent_dev. However,
dracut currently believes using /dev/mapper/mpath* could cause issues, thus
alternatively names are used, here it's /dev/disk/by-uuid/<FS_UUID>.
During the kdump boot progress, the /dev/disk/by-uuid/<FS_UUID> will exist as
soon as one of the path devices exists, but it won't be usable by systemd,
since multipathd will claim that device as a path device. Then multipathd will
get stopped before it can create the multipath device.
Without user_friendly_name, /dev/mapper/<WWID> is considered a persistent
device name, avoiding the issue.
The exit of multipathd is due to two dependencies in the current dracut module
90multipath/multipathd.service, "Before=initrd-cleanup.service" and
"Conflicts=initrd-cleanup.service".
As per man 5 systemd.unit, if A.service has "Conflicts=B.service", starting
B.service will stop A.service.
This is useful during normal boot. However, we will never switch-root after
capturing vmcore in kdump.
We need to ensure that multipathd is not killed due to such dependency issue.
Without modifying multipathd.service, we add ConditionPathExists=!/proc/vmcore
to skip initrd-cleanup.service in kdump. This approach is beneficial as
it avoid the potential termination of other services that conflict with
initrd-cleanup.service. Also skip initrd-parse-etc.service as it will try to
start initrd-cleanup.service. Both of these services are used for switch root,
so they can be safely skipped in kdump.
Suggested-by: Benjamin Marzinski <bmarzins@redhat.com>
Suggested-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Lichen Liu <lichliu@redhat.com>
Reviewed-by: Philipp Rudo <prudo@redhat.com>
Adding a patch to kexec-tools
=============================
There is a mailing list kexec@lists.fedoraproject.org where all the dicussion
related to fedora kexec-tools happen. All the patches are posted there for
inclusion and committed to kexec-tools after review.
So if you want your patches to be included in fedora kexec-tools package,
post these to kexec@lists.fedoraproject.org.
One can subscribe to list and browse through archives here.
https://admin.fedoraproject.org/mailman/listinfo/kexec
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