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https://issues.apache.org/jira/browse/AMBARI-4504?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Dmitry Lysnichenko updated AMBARI-4504:
---------------------------------------
Description:
h1. Implementation proposal
The most common use case for stack extension is adding new services or slightly
modifying existing ones. So typically child's RCO file should look like a diff
("What dependencies should we add to parent's RCO to support newly added
services?"). For more complex situations (when changes that are introduced by
child stack fundamentally change RCO), it makes sense to redefine a complete
RCO file instead of inheritance. That's why I propose to keep RCO file syntax
simple and don't implement support of deleting/modifying specific dependency or
dependency group.
We will support two options(policies) for stack extension:
- extend parent's RCO, appending dependencies specified at child's RCO to
corresponding groups of parent's RCO (default). For every dependency group,
parent's set of dependencies and child's set of dependencies are merged.
- completely override (replace) parent's RCO by child's RCO file.
Policy selection is done at stack metainfo.xml.
{code}
<metainfo>
<versions>
<active>true</active>
</versions>
<extends>2.0.5</extends>
<rco-policy>append</rco-policy>
<!-- or -->
<rco-policy>replace</rco-policy>
</metainfo>
{code}
If role_command_order.json file is absent at stack, parent's file is used.
Also, for every role_command_order.json file at inherited stacks, I'll add a
comment like:
{code}
This file appends role command order dependencies to ones defined at parent
stack. To change this behaviour, please refer to documentation about rco-policy
element of a stack metainfo.xml file.
{code}
Also, in debug mode, an effective RCO will be printed to log to simplify
troubleshooting.
was:
h1. Implementation proposal
The most common use case for stack extension is adding new services or slightly
modifying existing ones. So typically child's RCO file should look like a diff
("What dependencies should we add to parent's RCO to support newly added
services?"). For more complex situations (when changes that are introduced by
child stack fundamentally change RCO), it makes sense to have complete RCO file
instead of inheritance. That's why I propose to keep RCO file syntax simple and
don't implement support of deleting/modifying specific dependency.
So we will support two options(policies) for stack extension:
- extend parent's RCO, appending dependencies specified at child's RCO to
corresponding group of parent's RCO (default). For every dependency group,
parent's set of dependencies and child's set of dependencies are merged.
- completely override (replace) parent's RCO by child's RCO file.
Policy selection is done at stack metainfo.xml.
{code}
<metainfo>
<versions>
<active>true</active>
</versions>
<extends>2.0.5</extends>
<rco-policy>append</rco-policy>
<!-- or -->
<rco-policy>replace</rco-policy>
</metainfo>
{code}
Also, I'll add to every role_command_json file at inherited stacks a comment
like:
{code}
This file appends role command order dependencies to ones defined at parent
stack. To change this behaviour, please consult the documentation on rco-policy
element of a stack metainfo.xml file.
{code}
Also, in debug mode, an effective RCO will be printed to log to simplify
troubleshooting.
> role_command_order is not inherited from the parent stack
> ---------------------------------------------------------
>
> Key: AMBARI-4504
> URL: https://issues.apache.org/jira/browse/AMBARI-4504
> Project: Ambari
> Issue Type: Task
> Components: controller, test
> Affects Versions: 1.5.0
> Reporter: Dmitry Lysnichenko
> Assignee: Dmitry Lysnichenko
> Fix For: 1.5.0
>
>
> h1. Implementation proposal
> The most common use case for stack extension is adding new services or
> slightly modifying existing ones. So typically child's RCO file should look
> like a diff ("What dependencies should we add to parent's RCO to support
> newly added services?"). For more complex situations (when changes that are
> introduced by child stack fundamentally change RCO), it makes sense to
> redefine a complete RCO file instead of inheritance. That's why I propose to
> keep RCO file syntax simple and don't implement support of deleting/modifying
> specific dependency or dependency group.
> We will support two options(policies) for stack extension:
> - extend parent's RCO, appending dependencies specified at child's RCO to
> corresponding groups of parent's RCO (default). For every dependency group,
> parent's set of dependencies and child's set of dependencies are merged.
> - completely override (replace) parent's RCO by child's RCO file.
> Policy selection is done at stack metainfo.xml.
> {code}
> <metainfo>
> <versions>
> <active>true</active>
> </versions>
> <extends>2.0.5</extends>
> <rco-policy>append</rco-policy>
> <!-- or -->
> <rco-policy>replace</rco-policy>
> </metainfo>
> {code}
> If role_command_order.json file is absent at stack, parent's file is used.
> Also, for every role_command_order.json file at inherited stacks, I'll add a
> comment like:
> {code}
> This file appends role command order dependencies to ones defined at parent
> stack. To change this behaviour, please refer to documentation about
> rco-policy element of a stack metainfo.xml file.
> {code}
> Also, in debug mode, an effective RCO will be printed to log to simplify
> troubleshooting.
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