Commit Graph

39 Commits

Author SHA1 Message Date
Lianbo Jiang
50b3b4cb93 Doc: Improve the kdump sysconfig document
Currently, the kdump sysconfig document is missed, let's add it to
the kexec-kdump-howto.txt as a document in order to help users better
understand these options in the /etc/sysconfig/kdump.

Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
Acked-by: Kairui Song <kasong@redhat.com>
2021-01-12 16:46:44 +08:00
Lianbo Jiang
638167358f Doc: improve the usage documentation of the logger
Let's remove some redundant descriptions in the usage documentation
of the logger, and make it clear.

Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
Acked-by: Kairui Song <kasong@redhat.com>
2020-11-13 02:49:56 +08:00
Lianbo Jiang
3221f4e91f increase makdumpfile default message level to 7
Currently, the makedumpfile option '--message-level' is set to 1 when
dumping the vmcore, it only displays the progress indicator message,
but there are no common message and error message, it is important to
report some additional messages, especially for the error message,
which is very useful for the debugging.

In view of this, let's change the message level to 7 by default.

Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
Acked-by: Kairui Song <kasong@redhat.com>
2020-10-27 17:45:32 +08:00
Lianbo Jiang
d4c6f56456 Doc: add a documentation for the usage of logger
Because the logger is introduced to output the kdump logs, need to
add a documentation for this change and describe how to use it.

Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
Acked-by: Kairui Song <kasong@redhat.com>
2020-10-27 17:34:11 +08:00
Pingfan Liu
bc67c13651 kdump_pre: make notes more precise
Signed-off-by: Pingfan Liu <piliu@redhat.com>
Acked-by: Kairui Song <kasong@redhat.com>
2020-07-21 10:34:36 +08:00
Pingfan Liu
6dd2b9fb41 man: improve description about /etc/kdump/{pre.d,post.d}interface
The description is identical to the notes in kdump.conf

Signed-off-by: Pingfan Liu <piliu@redhat.com>
Acked-by: Kairui Song <kasong@redhat.com>
2020-07-01 16:49:41 +08:00
Kairui Song
846e23a2d5 Update docs for the new noauto dump target support
Signed-off-by: Kairui Song <kasong@redhat.com>
Acked-by: Pingfan Liu <piliu@redhat.com>
2020-05-22 16:16:01 +08:00
Kairui Song
f2ffa3d340 kexec-kdump-howto.txt: Add some format to the document
When adding doc for the non-mounted dump target support, I found the
document are a bit uneasy to read due to lack of a proper format, this
commit should it make looks better.

Signed-off-by: Kairui Song <kasong@redhat.com>
Acked-by: Pingfan Liu <piliu@redhat.com>
2020-05-22 16:14:13 +08:00
Kairui Song
3e8526cf04 kexec-kdump-howto.txt: Add notes about device dump
Currently there are two issues with device dump:
  - It may use too much memory
  - kdump won't automatically include required driver in second kernel

User should manually reserve enough memory, and include the required
driver by using extra_modules. Add some notes about the issues in
kexec-kdump-howto.txt

Signed-off-by: Kairui Song <kasong@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
2019-09-02 17:06:16 +08:00
Kairui Song
8d4db658fd kexec-kdump-howto.txt: Add document about encrypted targets
Currently kdump is not working well with encrypted targets, add document
about this issue.

Signed-off-by: Kairui Song <kasong@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
2019-05-20 13:41:44 +08:00
Kairui Song
f544a12e78 kexec-kdump-howto.txt: Add document about initramfs rebiuld
Add some note about the limitation of kdumpctl's auto detect and rebuild
feature, and suggest the user to rebuild the initramfs manually on
major system change, and don't include the initramfs in disk images.

Put the note about system change in front part of the document so user
will less likely to miss it.

Signed-off-by: Kairui Song <kasong@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
2019-05-20 13:41:28 +08:00
Baoquan He
50aa6dea24 kexec-kdump-howto: Add note on setting correct value of kptr_restrict
kdumpctl fails to load a crash kernel if KASLR is enabled.

The incorrect configuration of the kptr_restrict parameter causes that
the kdumpctl fails to load a crash kernel. The problem occurs when the
Kernel Address Space Layout Randomization (KASLR) mechanism is enabled.
The value of kptr_restrict decides how to expose the content of /proc
files. Inappropriate setting will cause that the /proc/kallsyms file is
being printed as all zeros. This configuration will break the kdump
loading process since it needs access to the conntent of /proc/kallsyms
if KASLR is enabled.

Set kptr_restrict to 1 to avoid the problem described above.

Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
2019-04-25 08:33:29 -04:00
Kazuhito Hagio
cc95f0a744 Add failure_action as alias of default and make default obsolete
In preparation for adding 'final_action' option, since it's confusing
to have the 'final_action' and 'default' options at the same time,
this patch introduces 'failure_action' as an alias of the 'default'
option to /etc/kdump.conf, and makes 'default' obsolete to be removed
in the future.

Also, the "default action" term is renamed to "failure action".

Signed-off-by: Kazuhito Hagio <k-hagio@ab.jp.nec.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Lianbo Jiang <lijiang@redhat.com>
Cc: Bhupesh Sharma <bhsharma@redhat.com>
Acked-by: Bhupesh Sharma <bhsharma@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Kairui Song <kasong@redhat.com>
2019-01-22 17:57:53 +08:00
Xunlei Pang
b22ed8dd3a kexec-kdump-howto: Add doc about the special mount information via "dracut_args"
Update "kexec-kdump-howto" to illustrate the usage of special mount
information via "dracut_args".

Reviewed-by: Pratyush Anand <panand@redhat.com>
Suggested-by: Dave Young <dyoung@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Xunlei Pang <xlpang@redhat.com>
2016-08-26 14:03:48 +08:00
Pratyush Anand
effd035e34 howto: Notes on watchdog module handling
Update howto with notes on dracut and kernel watchdog module handling.

Signed-off-by: Pratyush Anand <panand@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
2016-07-21 13:56:20 +08:00
Zhou Wenjian
cbe5943f9e kexec-kdump-howto:Add introduction of parallel dumping
Add descriptions of parallel dumping and how to use it.

Signed-off-by: Zhou Wenjian <zhouwj-fnst@cn.fujitsu.com>
Reviewed-by: Pratyush Anand <panand@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
2015-10-19 10:37:08 +08:00
Baoquan He
cad991814e kdumpctl: adjust the boot dir if kernel is put in sub dir of /boot
Previously /boot is asumed as the default dir where kernel and initrd
is put. However, the directory containing the running kernel image
on Atomic systems differs in each installation. Usually something like:

/boot/ostree/rhel-atomic-host-b50a015b637c353dc6554c851f8a1212b60d6121a7316715e4a63e2a4113cd72

This means that kdump will not find vmlinuz when installed on an
Atomic host, and thus the kdump service will fail to start.

In this patch, the kdump boot dir finding behaviour is a little changed.
Firstly check whether user has specify a directory explicitly in
/etc/sysconfig/kdump. If yes that is respected. Otherwise we assume
1st kernel and kdump kernel are put in the same place under /boot.
Then find it according /proc/cmdline and append it to /boot/

Note:
So now the KDUMP_BOOTDIR in /etc/sysconfig/kdump is set as empty
by default. If user set KDUMP_BOOTDIR to a directory, then he need to
take care of all related things himself. otherwise kdump script handle
it automatically.

Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Acked-by: Minfei Huang <mhuang@redhat.com>
2015-01-30 14:53:34 +08:00
Baoquan He
ddeec11f09 kexec-kdump-howto.txt: renew the path section
In case no target is specified explicitly in /etc/kdump.conf, the behavior
of path is changed, a check need be taken to see if any separate file
system is mounted on any tier of 'path', and also to take the relevant
action. Now the path section need be renewed accordingly.

Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
2014-04-17 11:27:31 +08:00
WANG Chao
fac2d59ae4 makedumpfile compression method default to lzo
Lzo is proven faster than zlib, for large memory machine it will
extremely shorten the time for saving vmcore. Let's switch to lzo as the
default compression method for makedumpfile.

The drawback is lzo has a little less compression ratio than zlib. But
considering for most users, speed/time is a more serious concern than
vmcore size. So I think default to lzo will benefit most of the users.

v1->v2: update kdump.conf.5 [DaveY]

Signed-off-by: WANG Chao <chaowang@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
2013-12-24 14:25:07 +08:00
Vivek Goyal
52972364dc kexec-kdump-howto: Add a section for debugging tips
Add a section for debugging tips. I had to spend some time to figure out
how to drop into a shell from kdump_pre/kdump_post scripts. So thought of
documenting that so that somebdoy else can save time.

Also add a method to log serial consoles for virtual machines. I was
loosing some of the messages over reboot. Logging to file is fine. This
can be helful in debugging.

v2: Add method to log serial console for virtual machines
v3: Fix serial console logging instructions.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
2013-06-25 14:01:57 +08:00
Baoquan He
5d73c78c8b kexec-kdump-howto: grubby is suggested modifing kernel cmdline
For reserving a chunk of memory for kdump kernel, args need be
appended to kernel cmdline. For different Arch, different
bootloaders and related config files are used, it's a little
annoying. Using grubby, it can be very easy to append a single
arg to kernel cmdline, and can save words in howto document.

Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: WANG Chao <chaowang@redhat.com>
2013-06-13 11:15:39 +08:00
Baoquan He
ca61e6a1bb kdump: Save vmcore-dmesg.txt before saving vmcore
Save vmcore-dmesg.txt before saving vmcore. For ssh targets, it assumes
that ssh is enabled. No scp logic as I don't have a local copy of
kernel log buffers and saving one will consume extra memory. We
can possibly enhance this logic to save kernel log buffers first locally
and then scp it (For setups which allow scp but disable ssh access).
(log is from Vivek Goyal <vgoyal@redhat.com>)

And add 1 section to describe it in kexec-kdump-howto.txt

v3->v4:
     Remove old description of dmesg in kexec-kdump-howto.txt, now
     add a new section to describe it, and note user kernel log
     buffers won't be available if dump target is raw device.

Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-05-14 11:17:55 +08:00
Baoquan He
603224b256 Change dump_to_rootfs to be a default option and reboot to be default action
Firstly rename dump_rootfs to dump_to_rootfs to remove the ambiguity
about dump_rootfs. Then add it as one of default options. That means
user can specify dump_to_rootfs to be default action manually, then
it will take action when specified target dump failed.

Secondly, in rhel7 and fedora, when default action is not specified,
the default 'default' is dump_to_rootfs. Namely when specified target
dump failed, the kdump initrd will mount root and save kdump from
initramfs context. However in rhel6, the default 'default' is 'reboot'.
That means when specified target dump failed, the kdump initrd will
reboot systems. For being consistent with rhel6, change the default
'default' back to 'reboot'. And this can also keep logic simple, easier
to understand. Primarily, Our default dump target is root filesystem.
So keeping "default" as "dump_to_rootfs" and trying to dump to root
filesystem again when first attempt fails does not make much sense.

Meanwhile add the relevant description into kdump.conf,kdump.conf.5
and kexec-kdump-howto.txt.

Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
2013-03-14 11:13:18 +08:00
Dave Young
f21cbb5165 handle readonly mounted filesystem
We need fs dump target being mounted firstly before creating mkdumprd
This is because we want to get the mount options from kernel mountinfo
instead of simply mount it without considering mount options.

To avoid the filesystem being used by something other than kdump we
suggest them to mount it as 'ro', mkdumprd will remount it as 'rw' when
necessary and remount it back to 'ro'

In 2nd kernel kdump will still use 'rw' to mount it though.

Tested local read-only mounted fs dump.

[v1->v2]: improve documentation
          add error handling for `mount -o remount,ro`

Fixed the changelog per Vivek's comment
The code was reviewed by Vivek.

Signed-off-by: Dave Young <dyoung@redhat.com>
2012-12-12 17:13:54 +08:00
Dave Young
fca70aadfd improve persistent name handling
For devices with filesystem, udev /dev/disk/by-uuid/* links are usually
reliable. But one exception is multipath devices, child and top layer
device may have same uuid.

As dm devices maintain /dev/mapper/* as persistent names, so converting to
/dev/mapper/* firstly then try by-uuid/* and by-id/*

Also because user know better what's the persistent name we just document well
to suggest user use persistent name in kdump.conf. it's suggested to
to use lvm or multipath canonical names or uuid/label.

Updated kdump.conf examples and related chunks in kexec-kdump-howto.txt
use lvm /dev/vg/<devname> in examples

Signed-off-by: Dave Young <dyoung@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
2012-10-11 09:43:30 +08:00
Dave Young
ffc5ece53b Resolves: bz808299
Copy comments from the bz:
In rhel7 onwards, we will require dump target filesystem to be mounted in first kernel so that kdump can make use of same mount options instead of trying to come up with its own mount options. This should make mounting that file system safer. Also it reduces complexity in kdump code.

That will mean one needs to put an entry for the dump file system in /etc/fstab
so that after reboot when kdump service starts, it can find the dump target and build initramfs instead of failing.
2012-08-31 10:05:37 +08:00
Dave Young
d965a9e105 The example of nfs dump config option is wrong.
s/net/nfs

Signed-off-by: Dave Young <dyoung@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
2012-08-31 10:04:54 +08:00
Dave Young
b47c0915d2 refactor net option
Currently net options means either nfs or ssh dump.
Better to split these two into standalone options. That's more clear to user.

after the split, ssh dump need user specify "ssh user@host"
nfs dump need user specify "nfs host:nfsshare"

Signed-off-by: Dave Young <dyoung@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
2012-07-23 15:31:28 +08:00
Dave Young
aa25382075 update kexec-kdump-howto.txt about systemctl commands
We should use systemctl instead of service to start/restart the kdump service
update kexec-kdump-howto.txt as well.

Signed-off-by: Dave Young <dyoung@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
2012-07-12 11:15:36 +08:00
Dave Young
f75f34b8a9 ssh propagate alert message fix
we now switched to systemd, 'service kdump propagate' does not work anymore.
update the alert message to use 'kdumpctl propagate'
vivek: update kexec-kdump-howto.txt as well.

Signed-off-by: Dave Young <dyoung@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
2012-07-12 11:15:36 +08:00
Dave Young
ec8e35a790 do not mount root twice
Resolves: bz821997

dracut will mount rootfs for us, so we need not pass root to fstab again here.
Here remove the root-mount line.

This will depends on the root=cmdline is right, by default kdump will
inherit it from /proc/cmdline.

Vivek: add document about the assumption for the root= cmdline issue.

Signed-off-by: Dave Young <dyoung@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
2012-07-12 11:15:35 +08:00
Dave Young
4e4a173698 Add kdump_post and kdump_pre support
Original patch is from Amerigo, but it has changed a lot:
remove multi dump
refreshed with latest git for the dump instruction function restructure
fixed the behavior of do_kdump_pre, if kdump_pre fails it will reboot
update the docs
check the existance and executable of kdump_pre/post files,
also check the timestamp of them for rebuilding.

refresh patch,
Address comments from vivek:
s/hush/bash in docs
fix the copy-paste error in kdump post error message
s/reboot\/halt/reboot in kexec-kdump-howto.txt

Signed-off-by: Dave Young <dyoung@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
2012-06-14 09:57:30 +08:00
Dave Young
2697669fa9 ssh core_collector fix
1. add core_collector filter support to ssh dump
2. scp can be specified in kdump.conf
3. error out if no '-F' with makedumpfile
4. add proper explanation and examples to kdump.conf[.5] and kexec-kdump-howto.txt.

v1->v2: add verify_core_collector function
v2->v3: optimize the code, remove local variable for default core_collector

Signed-off-by: Dave Young <dyoung@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
2012-06-14 09:56:10 +08:00
Dave Young
2aa51e665f core_collector doc basic fix
Update core_collector in kdump.conf[.5]:
1. accept <command> not limited to makedumpfile
2. add notes about default core_collector
3. add notes about flattened vmcore

Signed-off-by: Dave Young <dyoung@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
2012-06-11 10:57:53 +08:00
Dave Young
5d0335485d kdump.conf remove kdump_pre/kdump_post
kdump_post and kdump_pre are not implemented, remove them from kdump.conf[.5]

Signed-off-by: Dave Young <dyoung@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
2012-06-06 16:22:34 +08:00
Lubomir Rintel
dc002368a1 Pull EL6 kdump fixes into Rawhide Resolves: 597588 2010-06-13 19:20:48 +00:00
Neil Horman
fcd8cdc811 Resolves: 456572 2008-07-28 11:26:50 +00:00
Neil Horman
558bea7d40 Mass Update of RHEL5 patches 2008-06-05 15:18:53 +00:00
Neil Horman
9ac14dd3ed fixing bz 206861 2006-09-19 19:43:34 +00:00