[HEADS-UP] systemd for F14 - the next steps

[Hans de Goede]

Hi,

On 07/19/2010 07:33 PM, Lennart Poettering wrote:
> On Mon, 19.07.10 11:44, Mike Christie (mchristi at redhat.com) wrote:
>
>>> But if that's the case, why do you believe you gain anything by checking
>>> whether the root directory is on iscsi?
>>
>> For root on iscsi we always need it on.
>
> But what happens for /home on iscsi? It's the same story, isn't it? So
> why is / handled differently than /home in this respect?
>

There are 2 conditions on which the iscsid script starts iscsid:
1) / is on iscsi
2) Some previously discovered iscsi targets in the iscsi database
    /var/lib/iscsi are marked as automount

1) Is special because in this case the iscsi log in happens from the initrd,
and there should *not* be a re-login attempt when the iscsi initscript
(which runs after the iscsid script) does autologins, so the iscsi target
holding / is not marked as autostart (and autostop!!) in the iscsi database.
a target holding /home but not / would simply be marked autologin in the
iscsi database.

As Mike already said one option for F-14 is to simple make the iscsid service
default to off, and make anaconda turn it on when iscsi is used during
installation, and expect a sysadmin to enable it if he / she manually
configures iscsi after installation.

>> I think the problem was that the iscsid service was on by default, so
>> when things like libvirt install it iscsid would always start but many
>> times not be needed.
>
> In a systemd world we can fix this in a much nicer way:
> libvirtd.service would just have a "Wants: iscsid.service" in it. That
> way when libvirtd is started iscsid is started too. And if people use
> iscsid in other areas too they can just add a single symlink
> (/etc/systemd/system/multi-user.target.wants/iscsid.service →
> /lib/systemd/system/iscsid.service) and it is started on boot, regadless
> whether libvirtd is enabled or not.

I'm afraid that is not how the relation between libvirt and
iscsi-initiator-utils works. I don't know exactly what libvirt needs
iscsi-initiator-utils for, but I think it does not require
iscsid to be running. I guess we need to involve one of the
libvirt guys into this discussion to tell us what exactly libvirt uses
iscsi-initiator-utils for.

Regards,

Hans