<div dir="ltr">An aside on proper isolation:<div><br></div><div>This is actually available in the Waratek implementation of the JVM and should be standardized</div><div>in the JDK9 timeframe. Essentially this adds an interpretation of process isolation not dissimilar</div>
<div>to that found in Erlang but on the JVM. IBM's J9 has a preview of multi-tenant java as well:</div><div><br></div><div><a href="http://www.ibm.com/developerworks/java/library/j-multitenant-java/index.html?ca=drs-">http://www.ibm.com/developerworks/java/library/j-multitenant-java/index.html?ca=drs-</a><br>
</div><div><div><br></div></div><div>For folk on the JVM, say you have nice 48 core machine and you have 48 clients running</div><div>tomcat. What you do not want is 48 JVM instances running tomcat on that machine. Multi-tenant</div>
<div>Java adds virtualization and process isolation such that you can run one JVM instance and essentially</div><div>'share' a single tomcat instance to 48 tenants, each pinned to a core, or perhaps fixed to some cores and</div>
<div>time sharing other cores during burst periods etc..</div><div><br></div><div>This is great for things like corralling legacy JVM-based environments onto a single box to save</div><div>operational cost or for consolidating resource usage to maximise utilisation and so on. The virtualization</div>
<div>is basically transparent to the tenants and the hosts can meter based on kWh or bandwidth sent/received</div><div>etc..</div><div><br></div><div>It is possible to monitor (supervise) and to control tenants in much the same way as in OTP based</div>
<div>applications with multi-tenant JVM implementations. In Waratek's case this can be done via a JMX</div><div>based API.</div><div><br></div><div>But, multi-tenant JVMs with proper process isolation are new and easy to use APIs for monitoring,</div>
<div>supervision and control are yet to be defined and standardised. I would add to this that the Erlang</div><div>model is far simpler, just works and feels natural. It feels like voodoo on the JVM, frankly...</div><div>
<br></div><div>But 'proper isolation' as a feature is coming to the JVM and the Erlang model is providing</div><div>a source of inspiration here as it has already solved this particular problem within its own ecosystem.</div>
<div>It has been successful enough that it is influencing innovation within the JVM ecosystem, specifically</div><div>w.r.t. multi-tenancy which is becoming increasingly important in JVM deployments as Java loses ground</div>
<div>to dynamic languages in cloud-based *aaS environments.</div><div><br></div><div>Cheers,</div><div><br></div><div>Darach.</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Tue, Aug 26, 2014 at 10:20 PM, Jesper Louis Andersen <span dir="ltr"><<a href="mailto:jesper.louis.andersen@gmail.com" target="_blank">jesper.louis.andersen@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><br><div class="gmail_quote"><div class="">On Tue, Aug 26, 2014 at 9:34 PM, Youngkin, Rich <span dir="ltr"><<a href="mailto:richard.youngkin@pearson.com" target="_blank">richard.youngkin@pearson.com</a>></span> wrote:<br>
</div><div class=""><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Akka has been proposed as an alternative to Erlang.</blockquote></div></div><br>What are the arguments for Akka, as opposed to the arguments for Erlang?</div>
<div class="gmail_extra"><br></div><div class="gmail_extra">Library availability is definitely a valid concern. Yet, any library in any language will have errors and mistakes. A good point about Erlang is that the occasionally bad library tend to hurt your program less for the simple fact that proper isolation saves the day.<span class="HOEnZb"><font color="#888888"><br>
<br clear="all"><div><br></div>-- <br>J.
</font></span></div></div>
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