New mkdumprd for kdump
Summary
This is a replacement for mkdumprd of kexec-tools, to switch to dracut to generate the initrd for kdump kernel.
This feature was postponed in Fedora 16, because some feature needed in dracut was not done. Now the latest dracut has the thing we need, --mount, although it is still experimental.
Owner
- Name: Cong Wang and Dave Young
- Email: <xiyou.wangcong at gmail.com> or <amwang at redhat dot com> / ruyang@redhat.com
Current status
- Targeted release: Fedora 17
- Last updated: 2012-02-22
- Percentage of completion: 90%
Working:
- Dump to root filesystem
- Dump to local filesystem (including multiple targets)
- Part of configs in /etc/kdump.conf work:
- <fs type> <partition>
- path <path>
- core_collector <core_collector>
- extra_bins <bins>
- extra_modules <module(s)>
- default <reboot | halt | shell>
- Obsolete:
- disk_timeout <seconds>
- link_delay <seconds>
- options <module> <option list>
- Dump to remote host via ssh
- Depends on dracut ssh-client module (ruyang)
- Dump to remote host via nfs
- Depends on dracut nfs, network module and --mount
TODO:
- Dump to raw block device
- Implement full functionality of /etc/kdump.conf
- Dump to multiple targets
Detailed Description
Currently in kexec-tools we use our own /sbin/mkdumprd to generate an initrd for kdump kernel. However, due to the natural complexity of making a new initrd, we have lots of burdens to maintain the mkdumprd code, we decide to switch to using dracut to generate kdump initrd. And hopefully, we can provide a distro-independent mkdumprd to upstream, as dracut itself is cross-distribution.
Benefit to Fedora
The main source of kexec-tools bugs is in mkdumprd, with this change, hopefully we will reduce the number of bugs of kexec-tools.
Scope
All functionality of /sbin/mkdumprd has to be implemented and tested in this new mkdumprd.
How To Test
Enable some of the following config lines in /etc/kdump.conf
- Dump to local file system
ext3 LABEL=/boot
ext3 /dev/sda1
ext4 UUID=03138356-5e61-4ab3-b58e-27507ac41937
- Dump to remote machines
net my.server.com:/path
net user@remote.server.com
- Dump to raw block device
raw /dev/sda5
- Other configs
core_collector makedumpfile -c --message-level 1
core_collector cp
kdump_post /var/crash/scripts/kdump-post.sh
extra_bins /bin/cp
disk_timeout 30
extra_modules gfs2
options modulename options
default shell/reboot/shutdown
Trigger a crash and see if the vmcore is dumped to the right place.
User Experience
Users should not notice the replacement, because we plan to provide full backward compatibility.
Dependencies
Dracut
Contingency Plan
Fallback to old /sbin/mkdumprd.
Documentation
- kdump.conf: http://www.linuxcertif.com/man/5/kdump.conf/
Release Notes
- /sbin/mkdumprd has been replaced by new code, which uses dracut to generate the initrd for kdump kernel.