Bug 2181019

@kgaillot is there a crm_feature_set version I should check against so we can use new format where needed, and fallback to the old way for older versions?

(In reply to Oyvind Albrigtsen from comment #3)
> @kgaillot is there a crm_feature_set version I should check
> against so we can use new format where needed, and fallback to the old way
> for older versions?

3.7.4, which is also when --output-as=xml is available for crm_simulate

Fix to treat no "Transition Summary" as no actions:https://github.com/ClusterLabs/resource-agents/pull/1854

--output-as=xml is quite new in crm_simulate, so not as backwards compatible.

Additional patch to improve logic: https://github.com/ClusterLabs/resource-agents/pull/1864

Thank you for the fix. Will await release of package in repository channels for full integration tests on our side. Quick tests on RH9.0 and 8.6 are positive with the checked in modifications.

To clarify on the proposed fix - is there any concern of using crm_simulate -LS and depending on the output containing the expected text string in future releases, potentially breaking again down the line again? Certainly, future changes cannot be predicted, am trying to understand if there are assumed changes. Since -Ls output containing the 'Transition Summary:" text block was likely unintended and thus removed in the later/current releases, assuming -LS keeping it going forward. Any guidance on this would be appreciated.

(In reply to robbiro from comment #9)
> Thank you for the fix. Will await release of package in repository channels
> for full integration tests on our side. Quick tests on RH9.0 and 8.6 are
> positive with the checked in modifications.
> 
> To clarify on the proposed fix - is there any concern of using crm_simulate
> -LS and depending on the output containing the expected text string in
> future releases, potentially breaking again down the line again? Certainly,
> future changes cannot be predicted, am trying to understand if there are
> assumed changes. Since -Ls output containing the 'Transition Summary:" text
> block was likely unintended and thus removed in the later/current releases,
> assuming -LS keeping it going forward. Any guidance on this would be
> appreciated.

To address such issues, Pacemaker has been gradually adding support for XML output for all command-line tools. The idea is that the text output may change from release to release, but the XML output will change as little as possible, and remain backward-compatible as much as possible, for parsing by scripts. All commands will take the same --output-as option, which may be set to "none", "text", or "xml".

The schema for the XML output is installed as /usr/share/pacemaker/api/api-result.rng (which includes RNGs for each individual command). You can use that to figure out what to parse.

crm_simulate supports --output-as as of the Pacemaker 2.1.0 release (RHEL 8.5 and later, and all of RHEL 9). Most agents haven't switched to parsing XML yet in order to remain compatible with older versions, but if that's not a concern, I'd recommend the XML.

FYI, we've also been gradually adding high-level C APIs corresponding to each command-line tool, and those generate the same XML output that --output-as=xml would.

Commands that currently support --output-as=xml:
* Since 2.0.2 (8.1+/9.0+): stonith_admin
* Since 2.0.3 (8.2+/9.0+): crm_mon
* Since 2.1.0 (8.5+/9.0+): crmadmin, crm_resource, crm_simulate, crm_verify
* Since 2.1.3 (8.7+/9.1+): attrd_updater, crm_attribute, crm_rule
* Since 2.1.5 (8.8+/9.2+): crm_error
* Since 2.1.6 (8.9+/9.3+): crm_shadow
* Not yet supported: cibadmin, crm_diff, crm_node, crm_ticket, iso8601