[openstack-dev] Scheduler proposal

Joshua Harlow harlowja at fastmail.com
Mon Oct 12 15:35:20 UTC 2015

Thierry Carrez wrote:
> Clint Byrum wrote:
>> Excerpts from Joshua Harlow's message of 2015-10-10 17:43:40 -0700:
>>> I'm curious is there any more detail about #1 below anywhere online?
>>> Does cassandra use some features of the JVM that the openJDK version
>>> doesn't support? Something else?
>> This about sums it up:
>> https://github.com/apache/cassandra/blob/trunk/src/java/org/apache/cassandra/service/StartupChecks.java#L153-L155
>>      // There is essentially no QA done on OpenJDK builds, and
>>      // clusters running OpenJDK have seen many heap and load issues.
>>      logger.warn("OpenJDK is not recommended. Please upgrade to the newest Oracle Java release");
> Or:
> https://twitter.com/mipsytipsy/status/596697501991702528
> This is one of the reasons I'm generally negative about Java solutions
> (Cassandra or Zookeeper): the free software JVM is still not on par with
> the non-free one, so we indirectly force our users to use a non-free
> dependency. I've been there before often enough to hear "did you
> reproduce that bug under the {Sun,Oracle} JVM" quite a few times.

I'd be happy to 'fight' (and even fix) for any issues found with 
zookeeper + openjdk if needed, that twitter posting hopefully ended up 
in a bug being filed at https://issues.apache.org/jira/browse/ZOOKEEPER/ 
and hopefully things getting fixed...

> When the Java solution is the only solution for a problem space that
> might still be a good trade-off (compared to reinventing the wheel for
> example), but to share state or distribute locks, there are some pretty
> good other options out there that don't suffer from the same fundamental
> problem...

IMHO it's the only 'mature' solution so far; but of course maturity is a 
relative thing (look at the project age, version number of zookeeper vs 
etcd, consul for a general idea around this); in general I'd really like 
the TC and the foundation to help make the right decision here, because 
this kind of choice affects the long-term future (and health) of 
openstack as a whole (or I believe it does).


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