Coiby Xu <coxu(a)redhat.com> 于2022年4月25日周一 17:35写道:
On Mon, Apr 25, 2022 at 04:55:03PM +0800, Kairui Song wrote:
>Ok, thanks for the clarification.
You are welcome!
>
[...]
>> >
>> >Just one concern, could there be any wired DHCP corner case? Like if
>> >the kdump kernel took a longer time to boot, eg. 5 min, and then your
>> >DHCP IP just expired during that time window, the kdump kernel will be
>> >using an expired IP and conflict with other machines. The minimal
>> >lease time of DHCP address is 1 hr, could be a rare corner case, but
>> >in-theory possible.
>>
>> It seems I don't fully understand you. In the kdump kernel, we still use
>> DHCP to have a IP so there should be conflict. kdumpip is only used to
>> create to a dumping folder named "{IP}-{DATE}" and we don't
assign
>> kdumpip to a NIC.
>
>Oh, yes, you are right, I didn't read the patch carefully enough.
>Since kdumpip is only used to create the dump dir, then this is fine.
>
>Now I'm a bit concerned that kdumpip being embedded inside the initramfs.
>kdumpip could be dynamic, but the initramfs isn't. This is probably
>okay? since it's only used to naming the dump dir...
>
>IIUC, now the dump dir's ip prefix could be out-of-sync with the
>actual IP address of the machine when the dump happens, and will be in
>out-of-sync status for a long time until the initramfs get rebuilt.
>Just not sure if this will confuse anyone...
Thanks for coming up with this scenario! I thought in the case where we
have a different IP in the kdump kernel, the original IP of the 1st
kernel can better tell us where the dump happens. But I haven't took
the above scenario into consideration. How about we using FAQN i.e.
`hostname --fqdn` and the date to name the dumping folder instead?
Looks like a solution, just one thing I'm not sure, is `hostname
--fqdn` unique enough? If a lot of VMs are installed using the same VM
image (very common in many cloud environment), and the VM image all
have a fixed hostname, all dump dirs could have the same prefix...
> --
> Best regards,
> Coiby
>