[Pkg-iscsi-maintainers] Bug#850060: open-iscsi initramfs scripts do not start up iscsiuio deamon

[Andrew Patterson]

On 01/03/2017 01:02 PM, Christian Seiler wrote:
> Control: tags -1 + confirmed moreinfo
> Control: severity -1 wishlist
> 
> On 01/03/2017 06:02 PM, Andrew Patterson wrote:
>> Version 2.0.874 of the open-iscsi package requires that the iscsiuio
>> daemon to be running before iscsi hardware offload cards can login to
>> a LUN. The initramfs scripts used by open-iscsi to support boot from
>> iSCSI do no start up this daemon resulting in a failed boot.
> 
> I'd really like to support this setup. My idea how this could work
> would be along the lines of the following:
> 
>  1. In the local-top hook start iscsiuio before calling iscsistart -b
>     or iscsistart $params if the binary is present in the initramfs.
> 
>  2. In the iscsiuio package install a initramfs hook that copies the
>     iscsiuio binary (luckily it doesn't depend on any library) into
>     the initramfs.
> 
> Together that should start iscsiuio in the initramfs and allow
> login to the targets there - but if iscsiuio is not installed, the
> user won't see a difference from today.
>

That was my plan.

> However, there are still some questions I'd like to have answered
> before proceeding - and since I don't have the corresponding hardware
> I have no idea what the right answers are:
> 
> How does the rest of the boot process proceed then? What happens
> when iscsiuio is to be started regularly at boot from the systemd
> service / init script?
Is the iscsiuio from the initramfs required
> to be running at all times during the iSCSI session or can it be
> restarted, as long as the time during which that happens is brief
> enough? Is it required to be kept around during shutdown if it's
> on iSCSI?

I don't believe it needs to be running to support traffic, just when
doing logins. I will test to confirm.

Does it follow systemd's process name convention to make
> sure systemd doesn't kill it during shutdown?
>

I am looking into this. One thought is to start the daemon, do the
login, and then kill it. Then the normal sysvinit/upstart/systemd
scripts can restart it normally.

> Before I add the aforementioned steps 1 & 2 I'd like to be sure that
> this actually works properly beyond the initramfs. So any
> information related to that would be appreciated.

I am going to look at other package code to see how they handle daemon
startup. NFS comes to mind.


> 
> Regards,
> Christian
> 

-- 
Andrew Patterson
Hewlett-Packard Enterprise