Disallow setting order constraints on resources within a group

[F16shen]

Found an Issue when sets constraint on resources within a group:
I have a two node cluster and resources like this:

  * Resource Group: test:
    * dummy1	(ocf:pacemaker:Dummy):	 Started node1
    * dummy2	(ocf:pacemaker:Dummy):	 Started node1
    * dummy3	(ocf:pacemaker:Dummy):	 Started node1

and set an order constraint for dummy3 dummy1
pcs constraint order set dummy3 dummy1
It seems ok, but when I tried to move the group to another node, pcs reports error below

[root@node1 pcs]# pcs resource move test node2
Error: Unable to simulate changes in CIB: Transition failed: terminated
An invalid transition was produced

It looks like pacemaker doesn't allow this operation, but pcs has no warning about it(it really confused me until I delete that order constraint).Since resources in a group have their on boot sequence define by their position in the group, perhaps it's better to stop user set order constraint for them.

for now I still some complie issue unresolved, I thike it needs to modify tests but I'm not quite sure how to do it.

ERROR: pcs_test (unittest.loader._FailedTest)
----------------------------------------------------------------------
AttributeError: type object '_FailedTest' has no attribute 'pcs_test'

======================================================================
ERROR: test_returns_export_of_found_elements (pcs_test.tier0.lib.commands.test_constraint_common.ConfigTest)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/root/pcs/BUILD/pcs-0.10.12/pcs_test/tier0/lib/commands/test_constraint_common.py", line 198, in test_returns_export_of_found_elements
    {"ids": ["A", "B"], "options": {"role": "Master"}},
  File "/root/pcs/BUILD/pcs-0.10.12/pcs_test/tier0/lib/commands/test_constraint_common.py", line 190, in create
    {"id": "some_id", "symmetrical": "true"},
  File "/root/pcs/BUILD/pcs-0.10.12/pcs/lib/commands/constraint/common.py", line 48, in create_with_set
    resource_set.is_resource_in_group(resource_set_item['ids'], cib)
  File "/root/pcs/BUILD/pcs-0.10.12/pcs/lib/cib/constraint/resource_set.py", line 97, in is_resource_in_group
    resource_section = get_resources(cib)
  File "/root/pcs/BUILD/pcs-0.10.12/pcs/lib/cib/tools.py", line 457, in get_resources
    return sections.get(tree, sections.RESOURCES)
  File "/root/pcs/BUILD/pcs-0.10.12/pcs/lib/cib/sections.py", line 61, in get
    reports.messages.CibCannotFindMandatorySection(section_name)
pcs.lib.errors.LibraryError: ReportItem(severity=ReportItemSeverity(level='ERROR', force_code=None), message=CibCannotFindMandatorySection(section='configuration/resources'), context=None)

Thanks

[knet-ci-bot]

Can one of the admins verify this patch?

[tomjelinek]

test this please

[tomjelinek]

Hi @F16shen,

Thank you for reporting this issue and submitting a pull request.

There are, however, several serious issues with your fix:

• get_parent_resource returns None for resources which are not in a group, clone or bundle. If you pass that to group.is_group, as you do, it fails with a traceback.
• resource_set.is_resource_in_group is called from pcs.lib.commands.constrait.common.create_with_set unconditionally and therefore it applies to order constraints (which is good) as well as colocation and ticket constraints (which is not desired).
• On the other hand, the check is not applied for plain order constraints - pcs.constraint._order_add
• The check prevents creating a constraint if any resource in the constraint is in an arbitrary group. That seems to be unnecessarily strict. I think it would be sufficient to only disallow creating order constraint which apply to resources that are in the same group.

Also:

• If you called resource_set.prepare_set first and then is_resource_in_group, you wouldn't need to check if a resource exists. resource_set.prepare_set would do that for you.

[tomjelinek]

pcs.lib.errors.LibraryError: ReportItem(severity=ReportItemSeverity(level='ERROR', force_code=None), message=CibCannotFindMandatorySection(section='configuration/resources'), context=None)

Sorry about that, it's a bug in tests. I fixed it in #515 and #516.

[F16shen]

Hi @tomjelinek ,
I have fixed those issues you mentioned before, please check it when you are available.

[tomjelinek]

test this please

[F16shen]

Hi @tomjelinek ,
I have some problem when I try to get cib in resource_set.is_resource_in_same_group, when I import utils.py in resource_set.py it will cause a circular import in test.
I also tried to get cib when pcs.lib.cib.constraint.constraint.create_with_set is called, It also cause other test failed.
So now I only import it in resource_set.is_resource_in_same_group, is there a better way to do this?

[tomjelinek]

test this please

[tomjelinek]

Hi @F16shen, I fixed it for you.

[F16shen]

Thanks, this really help me a lot

[tomjelinek]

test this please

[tomjelinek]

retest this please

[tomjelinek]

retest this please

[tomjelinek]

retest this please