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Bug 1180390 - issue deleting resources with constraint
Summary: issue deleting resources with constraint
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: pcs
Version: 7.1
Hardware: Unspecified
OS: Unspecified
high
high
Target Milestone: rc
: ---
Assignee: Tomas Jelinek
QA Contact: cluster-qe@redhat.com
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2015-01-09 06:04 UTC by Fabio Massimo Di Nitto
Modified: 2015-03-05 09:20 UTC (History)
4 users (show)

Fixed In Version: pcs-0.9.137-10.el7
Doc Type: Bug Fix
Doc Text:
Cause: User deletes a resource. Consequence: Pcs removes constraints referencing the resource, stops the resource and removes it. This can cause the resource to be moved to other cluster node by pacemaker. Fix: Stop the resource before removing the constraints. Result: Resource is not moved to other cluster nodes.
Clone Of:
Environment:
Last Closed: 2015-03-05 09:20:55 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)
proposed fix (2.18 KB, patch)
2015-01-09 12:47 UTC, Tomas Jelinek 		no flags Details | Diff
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Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHBA-2015:0415 0 normal SHIPPED_LIVE pcs bug fix and enhancement update 2015-03-05 14:16:41 UTC

Description Fabio Massimo Di Nitto 2015-01-09 06:04:39 UTC 
Description of problem:

root@rhos6-node1 ~(keystone_admin)]$ pcs resource delete nova-compute
Removing Constraint - colocation-nova-compute-clone-ceilometer-compute-clone-INFINITY
Removing Constraint - order-ceilometer-compute-clone-nova-compute-clone-mandatory
Removing Constraint - order-nova-conductor-clone-nova-compute-clone-mandatory
Attempting to stop: nova-compute...Stopped
Deleting Resource - nova-compute

pcs resource delete operation ordering is dangerous.

Removing the constraints before stopping the resource has a race condition where the resource will be started on other nodes even for a few seconds, where things could go potentially very wrong.

The ideal sequence should be:

pcs resource delete nova-compute
Attempting to stop: nova-compute...Stopped
Removing Constraint - colocation-nova-compute-clone-ceilometer-compute-clone-INFINITY
Removing Constraint - order-ceilometer-compute-clone-nova-compute-clone-mandatory
Removing Constraint - order-nova-conductor-clone-nova-compute-clone-mandatory
Deleting Resource - nova-compute
Comment 1 Tomas Jelinek 2015-01-09 12:47:34 UTC 
Created attachment 978135 [details]
proposed fix
Comment 2 Tomas Jelinek 2015-01-09 16:01:59 UTC 
Before fix:
[root@rh70-node1:~]# rpm -q pcs
pcs-0.9.137-9.el7.x86_64
[root@rh70-node1:~]# pcs resource create dummy1 dummy --clone
[root@rh70-node1:~]# pcs resource create dummy2 dummy --clone
[root@rh70-node1:~]# pcs resource create dummy3 dummy --clone
[root@rh70-node1:~]# pcs constraint colocation add dummy1-clone dummy2-clone
[root@rh70-node1:~]# pcs constraint order dummy2-clone then dummy1-clone
Adding dummy2-clone dummy1-clone (kind: Mandatory) (Options: first-action=start then-action=start)
[root@rh70-node1:~]# pcs constraint order dummy3-clone then dummy1-clone
Adding dummy3-clone dummy1-clone (kind: Mandatory) (Options: first-action=start then-action=start)
[root@rh70-node1:~]# pcs resource delete dummy1
Removing Constraint - colocation-dummy1-clone-dummy2-clone-INFINITY
Removing Constraint - order-dummy2-clone-dummy1-clone-mandatory
Removing Constraint - order-dummy3-clone-dummy1-clone-mandatory
Attempting to stop: dummy1...Stopped
Deleting Resource - dummy1

After fix:
[root@rh70-node1:~]# rpm -q pcs
pcs-0.9.137-10.el7.x86_64
[root@rh70-node1:~]# pcs resource create dummy1 dummy --clone
[root@rh70-node1:~]# pcs resource create dummy2 dummy --clone
[root@rh70-node1:~]# pcs resource create dummy3 dummy --clone
[root@rh70-node1:~]# pcs constraint colocation add dummy1-clone dummy2-clone
[root@rh70-node1:~]# pcs constraint order dummy2-clone then dummy1-clone
Adding dummy2-clone dummy1-clone (kind: Mandatory) (Options: first-action=start then-action=start)
[root@rh70-node1:~]# pcs constraint order dummy3-clone then dummy1-clone
Adding dummy3-clone dummy1-clone (kind: Mandatory) (Options: first-action=start then-action=start)
[root@rh70-node1:~]# pcs resource delete dummy1
Attempting to stop: dummy1...Stopped
Removing Constraint - colocation-dummy1-clone-dummy2-clone-INFINITY
Removing Constraint - order-dummy2-clone-dummy1-clone-mandatory
Removing Constraint - order-dummy3-clone-dummy1-clone-mandatory
Deleting Resource - dummy1
Comment 6 errata-xmlrpc 2015-03-05 09:20:55 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHBA-2015-0415.html
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