path: root/doc/developer-guide
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authorShyamsundarR <>2018-07-19 08:37:15 -0400
committerAmar Tumballi <>2018-08-17 07:50:12 +0000
commit0058f6df0d2bd1dedc453585e6c4076df7b51fde (patch)
tree3f89a79d5a43e237a647448ad5fd2b08ec1a7b37 /doc/developer-guide
parent8f437f6c06587c3465764d1ec4b7f81d60a94eae (diff)
doc: Add details around xlator categories
Updates: bz#1193929 Change-Id: I6446bbdd8025f333a3e855032c0c7709bf4ae4cd Signed-off-by: ShyamsundarR <>
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+# xlator categories and expectations
+The purpose of the document is to define a category for various xlators
+and expectations around what each category means from a perspective of
+health and maintenance of a xlator.
+The need to do this is to ensure certain categories are kept in good
+health, and helps the community and contributors focus their efforts around the
+This document also provides implementation details for xlator developers to
+declare a category for any xlator.
+## Table of contents
+1. Audience
+2. Categories (and expectations of each category)
+3. Implementation and usage details
+## Audience
+This document is intended for the following community participants,
+- New xlator contributors
+- Existing xlator maintainers
+- Packaging and gluster management stack maintainers
+For a more user facing understanding it is recommended to read section [tbd](TBD)
+in the gluster documentation.
+## Categories
+1. Experimental (E)
+2. TechPreview (TP)
+3. Maintained (M)
+4. Deprecated (D)
+5. Obsolete (O)
+### Experimental (E)
+Developed in the experimental branch, for exploring new features. These xlators
+are NEVER packaged as a part of releases, interested users and contributors can
+build and work with these from sources. In the future, these maybe available as
+an package based on a weekly build of the same.
+#### Quality expectations
+- Compiles or passes smoke tests
+- Does not break nightly experimental regressions
+ - NOTE: If a nightly is broken, then all patches that were merged are reverted
+ till the errant patch is found and subsequently fixed
+### TechPreview (TP)
+Xlators in master or release branches that are not deemed fit to be in
+production deployments, but are feature complete to invite feedback and host
+user data.
+These xlators will be worked upon with priority by maintainers/authors who are
+involved in making them more stable than xlators in the Experimental/Deprecated/
+Obsolete categories.
+There is no guarantee that these xlators will move to the Maintained state, and
+may just get Obsoleted based on feedback, or other project goals or technical
+#### Quality expectations
+- Same as Maintained, minus
+ - Performance, Scale, other(?)
+ - *TBD* *NOTE* Need inputs, Intention is all quality goals as in Maintained,
+ other than the list above (which for now has scale and performance)
+### Maintained (M)
+These xltors are part of the core Gluster functionality and are maintained
+actively. These are part of master and release branches and are higher in
+priority of maintainers and other interested contributors.
+#### Quality expectations
+NOTE: A short note on what each of these mean are added here, details to follow.
+NOTE: Out of the gate all of the following are not mandated, consider the
+following a desirable state to reach as we progress on each
+- Bug backlog: Actively address bug backlog
+- Enhancement backlog: Actively maintain outstanding enhancement backlog (need
+ not be acted on, but should be visible to all)
+- Review backlog: Actively keep this below desired counts and states
+- Static code health: Actively meet near-zero issues in this regard
+ - Coverity, spellcheck and other checks
+- Runtime code health: Actively meet defined coverage levels in this regard
+ - Coverage, others?
+ - Per-patch regressions
+ - Glusto runs
+ - Performance
+ - Scalability
+- Technical specifications: Implementation details should be documented and
+ updated at regular cadence (even per patch that change assumptions in
+ here)
+- User documentation: User facing details should be maintained to current
+ status in the documentation
+- Debuggability: Steps, tools, procedures should be documented and maintained
+ each release/patch as applicable
+- Troubleshooting: Steps, tools, procedures should be documented and maintained
+ each release/patch as applicable
+ - Steps/guides for self service
+ - Knowledge base for problems
+- Other common criteria that will apply: Required metrics/desired states to be
+ defined per criteria
+ - Monitoring, usability, statedump, and other such xlator expectations
+### Deprecated (D)
+Xlators on master or release branches that would be obsoleted and/or replaced
+with similar or other functionality in the next major release.
+#### Quality expectations
+- Retain status-quo when moved to this state, till it is moved to obsoleted
+- Provide migration steps if feature provided by the xlator is replaced with
+other xlators
+### Obsolete (O)
+Xlator/code still in tree, but not packaged or shipped or maintained in any
+form. This is noted as a category till the code is removed from the tree.
+These xlators and their corresponding code and test health will not be executed.
+#### Quality expectations
+- None
+## Implementation and usage details
+### How to specify an xlators category
+### User experience using the categories
+#### Ability to use a category
+This section details which category of xlators can be used when and specifics
+around when each category is enabled.
+1. Maintained category xlators can be used by default, this implies, volumes
+created with these xlators enabled will throw no warnings, or need no user
+intervention to use the xlator.
+2. Tech Preview category xlators needs cluster configuration changes to allow
+these xlatorss to be used in volumes, further, logs will contain a message
+stating TP xlators are in use. Without the cluster configured to allow TP
+xlators, volumes created or edited to use such xlators would result in errors.
+ - (TBD) Cluster configuration option
+ - (TBD) Warning message
+ - (TBD) Code mechanics on how this is achieved
+3. Deprecated category xlators can be used by default, but will throw a warning
+in the logs that such are in use and will be deprecated in the future.
+ - (TBD) Warning message
+4. Obsolete category xlators will not be packaged and hence cannot be used from
+release builds.
+5. Experimental category xlators will not be packaged and hence cannot be used
+from release builds, if running experimental (weekly or other such) builds,
+these will throw a warning in the logs stating experimental xlators are in use.
+ - (TBD) Warning message
+#### Ability to query xlator category
+(TBD) Need to provide the ability to query xlator categories, or list xlators
+and their respective categories.
+#### User facing changes
+User facing changes that are expected due to this change include the following,
+- Cluster wide option to enable TP xlators, or more generically a category
+level of xlators
+- Errors in commands that fail due to invalid categories
+- Warning messages in logs to denote certain categories of xlators are in use
+- (TBD) Ability to query xlators and their respective categories