[jira] [Commented] (ACCUMULO-751) Support Wire Compatibility (between bugfix releases)

["Hudson (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/ACCUMULO-751?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13563080#comment-13563080 ] 

Hudson commented on ACCUMULO-751:
---------------------------------

Integrated in Accumulo-Trunk #672 (See [https://builds.apache.org/job/Accumulo-Trunk/672/])
    ACCUMULO-751 Switched from using the release version to an explicit wire version for on-the-wire compatibility. This will need to be manually updated when
thrift code changes between versions, or when interoperability is not possible between versions due to functional differences. (Revision 1438700)

     Result = SUCCESS
ctubbsii : 
Files : 
* /accumulo/trunk/core/src/main/java/org/apache/accumulo/core/Constants.java
* /accumulo/trunk/server/src/main/java/org/apache/accumulo/server/security/SecurityConstants.java

                
> Support Wire Compatibility (between bugfix releases)
> ----------------------------------------------------
>
>                 Key: ACCUMULO-751
>                 URL: https://issues.apache.org/jira/browse/ACCUMULO-751
>             Project: Accumulo
>          Issue Type: Improvement
>          Components: master, thrift, tserver
>    Affects Versions: 1.4.0
>            Reporter: Mike Drob
>            Assignee: Christopher Tubbs
>            Priority: Critical
>              Labels: api, compatibility, versioning, wire, wireprotocol
>             Fix For: 1.5.0
>
>
> With the advent of the HA NameNode in HDFS, the need for planned Hadoop outages has greatly diminished. I believe that Accumulo should follow suit and eventually allow for no-outage upgrades.
> To support this feature, we would require wire compatibility between different versions so that the cluster can continue to function in a mixed state. There are already contingencies for master fail-over and tservers to leave/join the cluster, so I think this is a natural extension of that code.
> To accomplish this for bugfix releases should be trivial. I think it is only necessary to remove (or relax) the version check that happens when a tserver attempts to join. There are rarely (never?) changes to the thrift protocol between bugfix releases, so theoretically a 1.4.1 tserver is already compatible with a 1.4.0 master and vice versa.
> To maintain compatibility in the face of thrift protocol changes is certainly a harder challenge, which might be best reserved for a separate ticket.

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