disable_rollback will change to true although we don't specify it when stack-update

[Ethan Lynn]

Steps:
heat stack-create -f aa.template -P flavor=m1.tiny --enable-rollback
heat stack-update -f aa.template -P flavor=m1.small

Result:
When update action is failed, no rollback action is going.

Since this patch (https://review.openstack.org/#/c/79721) override disable_rollback value to true,
no rollback action will take after update failed.

I think disable_rollback should inherit from oldstack if we don't specify it when stack-update.
Or add option --enable-rollback to stack-update cli.

[Ethan Lynn (ethanlynn)]

There is a patch for cli and pending to review.
https://review.openstack.org/#/c/94004

[Pavlo Shchelokovskyy (pshchelo)]

I still think that it would be more intuitive to update call default to disable_rollback == None, which would use the previous value, and have two separate switches for overriding/ensuring the value used during update. The heat itself then would need to figure out if to use the already present value or override it.

As the patch in review mentioned is more of a workaround, I'm adding python-heatclient to the affected projects.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/94004
Committed: https://git.openstack.org/cgit/openstack/python-heatclient/commit/?id=83d9485f3108e222f2f0ec5ba3b9ed7c93cb1471
Submitter: Jenkins
Branch: master

commit 83d9485f3108e222f2f0ec5ba3b9ed7c93cb1471
Author: Zhang Yang <email address hidden>
Date: Fri May 16 19:42:04 2014 -0700

    Add shell arguments for stack update

    add option timeout for do_update,which has been added
    for do_stack_update already.

    add option rollback for stack update, this is supported
    already in heat[1].

    [1]https://github.com/openstack/heat/commit/7c833ecc2ba27053b7e948667a39a261f68144b5

    Change-Id: I4545aef556c4c3297c2993418df2ec2cd7c4e408
    Partial-Bug: #1324366

[Pavlo Shchelokovskyy (pshchelo)]

I poked around in heat to see how disable_rollback=None could be implemented. To me it looks like not a good solution now, as currently we have disable_rollback well defined as Boolean. Adding None to its possible values adds too much inconsstency, especially as current default value is True, and we want to store an actual Bool in the database, so that every actual stack has it well defined.

What would you say about the next approach then:

* Change nothing in Heat

* in python-heatclient
   - add two explicit swithces '--enable-rollback' and '--disable-rollback' for stack-update
   - when both new switches are absent, make a lookup similar to heat stack-show and put the value from existing stack
     in the update call

I realize it is an extra API call, but I think it would be a clearer solution.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/100245

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/117271

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/117271
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=007949f0c7b3fe68cf3ff32bc36cdd3b5ef10088
Submitter: Jenkins
Branch: master

commit 007949f0c7b3fe68cf3ff32bc36cdd3b5ef10088
Author: Pavlo Shchelokovskyy <email address hidden>
Date: Wed Aug 27 17:41:16 2014 +0300

    Reuse disable_rollback on stack update

    If disable_rollback API parameter is not supplied to stack update,
    use corresponding value of existing stack.

    Change-Id: Iad60e12d31dc3850071dc0b8562c7b99f53adba4
    Closes-Bug: #1324366

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/100245
Committed: https://git.openstack.org/cgit/openstack/python-heatclient/commit/?id=847a8fd566e5c85399d2a933e8cf2818095f4849
Submitter: Jenkins
Branch: master

commit 847a8fd566e5c85399d2a933e8cf2818095f4849
Author: Pavlo Shchelokovskyy <email address hidden>
Date: Thu May 29 16:22:03 2014 +0300

    Reuse existing disable_rollback in stack-update

    This patch makes `stack-update` command to change the `disable_rollback`
    bit of the stack IF AND ONLY IF explicitly requested on CLI.

    In order to facilitate this, `--rollback` CLI argument to `stack-update`
    is added (accepting values from 1, on, true, t, 0, off, false, f and similar)
    to explicitly set disable_rollback property of the stack on stack update.
    If this argument is omitted, the value of disable_rollback
    of the stack to be updated will be implicitly used by heat engine.

    The boolean switch '--enable-rollback' is deprecated with appropriate
    message (although the default behavior is effectively changed).

    Change-Id: I235198ec04bfb192fcbfa4e2e3e618b64c99d3df
    Closes-Bug: #1324366