[openstack-dev] [all] [dlm] Zookeeper and openjdk, mythbusted

Joshua Harlow harlowja at fastmail.com
Fri Nov 6 18:55:14 UTC 2015

I just wanted to bring this up in its own thread as I know it was a 
concern of (some) folks at the DLM session in tokyo[0] and I'd like to 
try to bust this myth using hopefully objective people/users of 
zookeeper (besides myself and yahoo, the company I work for) so that 
this myth can be put to bed.

Basically here is the TLDR of the question/complaint:

Zookeeper, a java application, will force you to install oracles virtual 
machine implementation for it to work, and it doesn't work with the 
openjdk, and if tooz (and oslo library) has a capable driver that uses 
zookeeper internally (via kazoo @ http://kazoo.readthedocs.org) then it 
will force deployers of openstack and its components that will use more 
of tooz to install oracles virtual machine implementation.

This will not work!!
There is no way I can do that!!
Yell!! Shout!! Cry!!

That's the *jist* of it (with additional dramatization included).

So in order to dispel this, I tried in that session to say 'actually I 
have heard nothing saying it doesn't work with openjdk' in that session 
but the voices did not seem to hear that (or they were unable to listen 
due to there emotions stressed/high). Either way I wanted to ensure that 
people do know it does work with the openjdk and here is a set of 
testimonials from real users of zookeeper + openjdk that it does work there:

 From Min Pae[1] on the Cue[2] team:

<@sputnik13> harlowja for what it's worth we use zookeeper with openjdk

 From Greg Hill[3] who works on the rackspace bigdata[4] team:

<jimbobhickville> and yes, we run Zookeeper on openjdk, and we haven't 
heard of any problems with it

 From Joe Smith[5][6] (who is at twitter, and is the Mesos/Aurora SRE 
Tech Lead there):

<Yasumoto> and yep, we (twitter) use zookeeper for service discovery
<Yasumoto> someone asked me that question back at mesoscon in seattle, 
fwiw https://youtu.be/nNrh-gdu9m4?t=34m43s
<harlowja> Yasumoto do u know if u use openjdk or oraclejdk?
<Yasumoto> harlowja: yep, openjdk7
<Yasumoto> but we're migrating up to 8

 From Martijn Verburg who is an an openjdk developer (and CEO)[7][8] 
that has some insightful info as well:

So OpenJDK and Oracle JDK are almost identical in their make up 
*especially* on the server side. Many, many orgs like Google, Twitter, 
the biggest investment bank in the world, all use OpenJDK as opposed to 
Oracle's JDK.


The difference is the quality of the OpenJDK binaries built and released 
by package maintainers.

If you are getting IcedTea from RedHat (their supported OpenJDK binary) 
or Azul's Zulu (Fully supported OpenJDK) then you're *absolutely fine*.

If you're relying on the Debian or Fedora packages then *occasionally* 
those package maintainers don't put out a great binary as they don't run 
the TCK tests (partly because they can't as they are unwilling/unable to 
pay Oracle for that TCK).

Hope that all makes sense...

So I hope the above is enough of *proof* that yes the openjdk is fine, 
there may have been some bugs in the past, but those afaik have all been 
resolved and there are major contributors stepping up (and continuing to 
step up) to make sure that zookeeper + openjdk continue to work (because 
companies/projects/people... like mentioned above depend on it).


[0] https://etherpad.openstack.org/p/mitaka-cross-project-dlm
[1] https://launchpad.net/~sputnik13
[2] https://wiki.openstack.org/wiki/Cue
[3] https://launchpad.net/~greg-hill
[4] http://www.rackspace.com/cloud/big-data
[5] http://www.bjoli.com/
[6] https://github.com/Yasumoto
[7] http://martijnverburg.blogspot.com/
[8] http://www.infoq.com/interviews/verburg-ljc

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