On 2016/05/27 at 11:19, Pratyush Anand wrote:
On 26/05/2016:09:08:05 PM, Xunlei Pang wrote:
> Update "kexec-kdump-howto" to illustrate the usage of special mount
> information via "dracut_args".
>
> Suggested-by: Dave Young <dyoung(a)redhat.com>
> Signed-off-by: Xunlei Pang <xlpang(a)redhat.com>
> ---
> kexec-kdump-howto.txt | 31 +++++++++++++++++++++++++++++++
> 1 file changed, 31 insertions(+)
>
> diff --git a/kexec-kdump-howto.txt b/kexec-kdump-howto.txt
> index b4cdc22..f7c6811 100644
> --- a/kexec-kdump-howto.txt
> +++ b/kexec-kdump-howto.txt
> @@ -345,6 +345,37 @@ mount the NFS mount and copy out the vmcore to your NFS server.
Restart the
> kdump service via '/sbin/systemctl restart kdump.service' to commit this
change
> to your kdump initrd.
>
> +Special mount via "dracut_args"
> +
> +Kdump uses dracut to generate initramfs for second kernel. This option
> +allows a user to pass arguments to dracut directly.
> +
> +Users can utilize "dracut_args" to pass "--mount" to kdump,
please refer
> +to "man dracut" for the format of "--mount" argument. If there
is any
> +"--mount" specified via "dracut_args", kdump always uses it as
the final
> +mount target without any validation(mounting or checking like mount options,
> +fs size, save path, etc), so users are expected to ensure all the correctness.
> +It conflicts with targets specified via "ext[234]/xfs/btrfs/nfs".
> +
> +This is useful when we want to deploy thoundsands of diskless clients using
> +nfs dumping and share the same nfs server. In this scenario, each time the
> +clients are booting up, the kdump initramfs rebuild will be triggered due to
> +the diskless environment, so all the clients will request nfs mount simultaneouly,
> +thereby imposing very much burdon on the shared nfs server. With the help of
^^^^^^^^^
Probably "too much" would have been better wording..
Indeed, thanks!
Regards,
Xunlei
> +special mount via "dracut_args", kdump can skip mounting and resolve the
issue.
> +Because nfs needn't to be mounted beforehand, some nfs-related ko modules will
> +be explicitly specified as needed together in the "dracut_args"(or via
directive
> +"extra_modules" in /etc/kdump.conf). As an nfs mount example:
> +dracut_args --mount "192.168.1.1:/test /test nfs defaults" --add-driver
"nfs nfsv4"
> +
> +NOTE:
> +-Only one mount target is allowed using "dracut_args" globally.
> +-Dracut will create <mountpoint> if it doesn't exist in kdump kernel,
> + <mountpoint> must be specified in an absolute path.
> +-There must be double quotation marks behind "--mount", i.e. --mount
"<mount info>".
> +-Users should do a test first and ensure it works, because kdump does
> + not prepare the mount and check all the validity.
> +
> Remote system via ssh/scp
>
> Dumping over ssh/scp requires setting up passwordless ssh keys for every
Other than that
Reviewed-by: Pratyush Anand <panand(a)redhat.com>