Here requirement is to bring down a payload node and delete its related
configuration like node, MW SI, MW SU etc. As per AMF PR doc section "7.1.4 ",
SI must be locked before deleting it. Also AMF allows deletion of SI in
unlocked state if it is unassigned but it is not the recommended way. Since
lock operation on NoRed MW SI is not allowed, the only way to delete is when it
is unassigned. This imposes another criterion to bring down the node or lock
NoRed SU so that its MW SI gets unassigned and its deletion can proceed. Even
in this case also, AMF can pick the same SI and assign it to some other
unassigned node or any node joining the cluster that time. Thus there is no
gauantee that SI will remain unassigned.
As a first approach to solution, lock operation on MW NoRed SI can be
supported. It will be aligned with AMF spec also. Lock of MW 2N SI will not be
allowed as there must be one Active controller in the system.
There can be a second approach to solve this problem. In this reported case, SI
was unassigned when active AMFD processes CCB complete cbk for deletion and it
becomes assigned at the time of processing CCB Apply cbk. This can happen for
any configurable entity because of time gap between CCB complete and apply
callback. So one fix can be to check for any pending CCB Apply cbk for deletion
before using the entity. If this approach is applied to this problem, then AMFD
should not assign NoRed SI as it is going a CCB delete operation.
This is the first time such a case has been reported. Since for MW NoRed SI, it
can be handled by supporting lock operation on it, I would be publishing a
patch that will allow lock and unlock operation on MW NoRed SI. But in future,
if more problems originates because of same reason then second approach may
become the preferred one.
---
** [tickets:#1834] amf: amfd crashes during deletion of MW NoRed SI while
standby SC is coming up.**
**Status:** accepted
**Milestone:** 4.7.2
**Created:** Tue May 17, 2016 09:16 AM UTC by Praveen
**Last Updated:** Tue May 17, 2016 09:16 AM UTC
**Owner:** Praveen
**Attachments:**
-
[amfd_crashes.tgz](https://sourceforge.net/p/opensaf/tickets/1834/attachment/amfd_crashes.tgz)
(145.3 kB; application/x-compressed)
Steps to reproduce:
1)Bring up one controller up (say SC-1).
2)While bringing up second controller up(SC-2), try to delete the NoRed MW SI
to be assigned on SC-2. Issue comes when CCB opoerations related callbacks are
timed in this order:
-Completed callback must come when NoRed SI is not assigned for standby
controller. So in this case, Active controller will ack for completed cbk to
imm.
-Now before active AMFD gets the apply callback, NoRed si must gets
assigned,
-After this, active AMFD gets the apply callback and it deletes the SI and
also remove the assignment from the component on standby.
3) NoRed SI is not available on standby so it crashes while trying to accessin
MBCV checkpointing.
In this case standby amfd could not read it from IMM as it was deleted
before that.
4) Active amfd also crashes, while trying to do nodefailover of SC-2 as it
does not find NoRed SI.
Since it is related to timing, reproduced by preparing a patch to force AMFD to
assign NoRed SI in between completed and apply callback. Attached are amfd
traces and bts from both the controllers and also the repr.patch.
---
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