[openstack-dev] [cinder][nova]May I run iscsiadm --op show & update 100 times?

Rikimaru Honjo honjo.rikimaru at po.ntt-tx.co.jp
Mon Oct 2 02:59:18 UTC 2017


I'd like to discuss about the following bug of os-brick.

* os-brick's iscsi initiator unexpectedly reverts node.startup from "automatic" to "manual".

The important point of this bug is:

When os-brick initializes iscsi connections:
1. os-brick will run "iscsiadm -m discovery" command if we use iscsi multipath.
2. os-brick will update node.startup values to "automatic" if we use iscsi.
3. "iscsiadm -m discovery" command will recreate iscsi node repositories.[1]
    As a result, node.startup values of already attached volumes will be revert
    to default(=manual).

Gorka Eguileor and I discussed how do I fix this bug[2].
Our idea is this:

1. Confirm node.startup values of all the iscsi targets before running discovery.
2. Re-update node.startup values of all the iscsi targets after running discovery.

But, I afraid that this operation will take a long time.
I ran showing & updating node.startup values 100 times for researching.
As a result, it took about 4 seconds.
When I ran 200 times, it took about 8 seconds.
I think this is a little long.

If we use multipath and attach 25 volumes, 100 targets will be created.
I think that updating 100 times is a possible use case.

How do you think about it?
Can I implement the above idea?

[1]This is correct behavior of iscsiadm.
Rikimaru Honjo
E-mail:honjo.rikimaru at po.ntt-tx.co.jp

More information about the OpenStack-dev mailing list