Thank you for your review and all these great suggestions.
On Wed, Oct 12, 2016 at 4:36 PM, Dave Young <dyoung(a)redhat.com> wrote:
On 10/11/16 at 02:50pm, Tong Li wrote:
> This is a short documentation on how to setup kdump on live images. All
steps
> was tested on Fedora 25 Alpha LiveCD and successfully saved vmcore
captured
> by kdump to a USB stick.
>
> Signed-off-by: Tong Li <tonli(a)redhat.com>
> ---
> kdump-live-images.txt | 25 +++++++++++++++++++++++++
> 1 file changed, 25 insertions(+)
> create mode 100644 kdump-live-images.txt
>
> diff --git a/kdump-live-images.txt b/kdump-live-images.txt
> new file mode 100644
> index 0000000..32f4d2d
> --- /dev/null
> +++ b/kdump-live-images.txt
The file name is misleading, how about live-image-kdump-howto.txt
> @@ -0,0 +1,25 @@
> +Kdump now can work on Live images, but some manual configurations are
needed.
How about simpler sentence below:
"Kdump works on live images with some manual configurations."
> +Here is the step by step guide. Please use root privilege.
No need to mention about the root privilege here..
> +
> +0. (if you are using old versions of kexec-tools)
Although I like start with '0' I think we still need refer to other
kdump documentation and be consistent. Seems we have been using 1), 2)..
Could you follow and use same format?
I started from 0 because the previous patch have be merged. Of course this
paragraph
should be dropped after that patch is in the tree.
Btw, no need mention the old versions steps, because I assume this
patch
depends on the previous patch to drop root=live:
> + Apeend "root" to KDUMP_COMMANDLINE_REMOVE variable in
/etc/sysconfig/kdump
> +
> +Live images are booted with a kernel parameter which looks like
> +"root=live:CDLABEL=Fedora-WS-Live-25_A-2". This argument can't be
recognized
> +by dracut during kdump process and will cause failure of kdump. So we
need
> +to make sure 'root' parameter is removed during kdump process.
Above paragraph can be dropped because of the privous patch.
> +
> +1. Change dump target in /etc/kdump.conf
> +
> +When kdump is triggered in a Live environment, the default target
/var/crash
> +will not be mounted and unable to be used to save vmcore. You can
modify it to
> +make kdump save the captured dump file on an external disk or send it
with ssh
> +throught network.
> +will not be mounted and unable to be used to save vmcore. You can
> modify it to
> +make kdump save the captured dump file on an external disk or send it
> with ssh
> +throught network.
When kdump kernel boots in a live environment, the default target
/var/crash is in in ram so you need change the dump target to an
external disk or an network dump target.
> +
> +2. Run 'kdumpctl start' to build kdump initramfs and start kdump.
> +
> +Here is all configurations you need to tweak manually. If you want to
confirm
> +whether kdump is working or not, you can use sys-trigger interface by
running:
Change above 2 lines to below should be enough:
3) Trigger a kdump test:
> +
> + $ echo 1 > /proc/sys/kernel/sysrq
> + $ echo c > /proc/sysrq-trigger
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Seems the crashkernel setup is missing, it should be the first step:
1) Enable crashkernel reservation
...
Sorry for this missing. Adding it.
I do not now if livcd can have a config file so that we can boot
with
an appended cmdlien params, does Fedora live supports that?
Thanks
Dave
I didn't find any clues from Fedora's installation document.
It seems we have to append "crashkernel" argument every time
we get booted into boot menu.
Regards,
--
Tong