[Xen-API] PATCH: fix support for multiple target's IPs for ISCSI-based SR's with multipathing (version 2)

[George Shuklin <george.shuklin@xxxxxxxxx>]

Sorry, guys, I do a little patch modification.

Changes:
+ now names resolved to IP before probing
+ now we can attach to multihomed target even if some of it's IP is down
(note, that we will not attach to recovered hosts automatically, you
will needed to do iscsi login manually or replug pbd).
! We will silently fail to process any unrecognized strings/bad IP in
targetlist - because we can not distinct between target host in disaster
state and garbage in XCP config. But we still reject pbd with no live
IP's (where we can not connect in any way).


... and little question: is sleep(5) after iscsi call is required?
(ISCSISR.py) It looks kinda lame.


Ð ÐÑÐ, 19/05/2011 Ð 02:00 +0400, George Shuklin ÐÐÑÐÑ:
> Good day.
> 
> Few days ago I have found strange behavior: LVMoISCSI SR with
> multipathing and two target's IPs  does not login to second portal
> target - only 1st target's IP was processed. This problem was confirmed
> in XCP 0.5 and XCP 1.0 (and, I believe is XCP 0.1.1 if someone still
> using it).
> 
> I dig a little and with help from this maillist found strange code in
> ISCSISR.py. Patch to fix this behavior in attachment. (We simply iterate
> targetlist instead using a one target portal we succeeded to test
> early).
> 
> More about configuration where this problem appear:
> 
>                                     iscsi (ip1)
>            +------- HOST1(TARGET1)-----------------+
> BLOCK-DEVICE                                      XCP_host(initiator)
>            +------- HOST2(TARGET2)-----------------+
>                                     iscsi (ip2)
> 
> in this case we have TWO different portals, announcing same IQN with
> same serial and so on.
> 
> If we put them both to device-config:target, only first one will be
> used, this patch add support for both of them.
> 
> 
> sample command to see difference:
> 
>  xe sr-create type=lvmoiscsi \
>  device-config:target=10.0.0.1,10.0.0.2 \ 
>  device-config:multihomed=true \
>  device-config:targetIQN=iqn.2011-05.test:test.test \
>  device-config:SCSIid=1494554000000000031000000000000000000000000000000
> name-label=test
> 
> PS patch is against XCP 1.0, but shall works fine with XCP 0.5 too.
> 
> PPS This problem appear only if we have a DIFFERENT target hosts. Single
> target with few available paths will send all it addresses via single
> discovery process, so if target is single host, problem will not appear.

Attachment: xcp-iscsisr-multipath-multiaddress-support.patch
Description: Text Data

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