Application auto-scaling in the BlueMix vs. OpenShift

Application auto-scaling in PaaS enables your application to react to changes in workload and automatically allocate the necessary resources to handle your current demand without an administrator having to do it by hand. In my earlier post I explained and demonstrated how WAS ND Liberty Profile and Full Profile provide auto-scaling for on-prem applications. None of the other application servers provide the auto-scaling functionality found in WebSphere Application Server. However some PaaS platforms are trying to fill this gap. For example, Red Hat OpenShift does have an auto-scaling capability that can be used to scale JBoss EAP gears and other web gears automatically. Lets take a look at the differences between BlueMix and OpenShift auto-scaling (see respective IBM and Red Hat documentation on this topic).

You may want to watch the IBM BlueMix auto-scaling demo to understand how it works in practice.

While many PaaS vendors claim to do similar things, the devil is in details (as always). BlueMix and OpenShift Online both claim to provide auto-scaling capability for Java Application Servers, however there are significant differences in how it is implemented and how the user can control it. It turns out that BlueMix provides a lot more granular control over the auto-scaling decision process. Take a look at the comparison below – I think the difference is pretty clear.

BlueMix OpenShift Online
User defined scaling metrics:
JVM Heap Yes No
Memory Yes No
Throughput Yes No
Response time Yes No
# of connections No Yes
User controlled options:
Breach duration Yes No
Statistic window Yes No
Cooldown period for scaling in & out Yes No
Scale in & out instance count Yes No
Max & min instance count Yes Yes

To be fair to Red Hat, there is a capability to write your own auto-scaling plugin for OpenShift as described in this article, however the average user is not likely to embark on this endeavor as it is fairly easy to bring havoc into the application by introducing an error in a complex hand written script.

Categories: Technology

Tags: , , , , ,

11 replies

  1. Yes, this article looks obselete as v2 is history. and Btw, auto-scaling was enabled in v2 as well. You can still go to which is on v2 (v3 should be coming on online version this year sometime) and provision a say EAP server with auto-scaling option ON. You should put a disclaimer on this article that this is based on author assumptions..


    • Thanks for clarification. I made an update to make it clear that this article is comparing OpenShift **Online** (latest as of today). If v2 is obsolete, why is it not replaced with v3 for the Online offering? Everything in this article is 100% as of today in relation to the latest OpenShift Online. I would love to hear from you when v3 is available for the cloud users.


      • Roman, you would have to make quite some correction in your blog. (i) Auto-Scaling can be done right now. Please go and choose EAP as your cartridge for eg and you will have an option to choose scale with web-traffic (ii) Metrics like CPU, Memory, Storage depends on the gear size you choose. You can go with paid version of and choose large gears which come with more resources. v2 is still in support and clients are using it.


      • Yes indeed – I agree with what you say above, however that is not my point. My post describes automatic scaling options – not manual such as those you propose above. Thus far everything in my post is correct as it relates to the current available offering of OpenShift Online.


  2. Looks like you are comparing against Openshift v2. OSE V3 was released earlier this year and is based on kubernetes / Docker. Everything has changed in v3. 😉

    Maybe this article should be updated or at least call out that you are comparing against v2.

    Liked by 1 person

    • I am comparing to the latest and greatest OpenShift Online (which I understand is based on v2). I just tested auto-scaling 5 minutes ago on the OpenShift Online and all I get is what is documented in this blog post. Latest documentation (link in the blog post above) describes exactly the same thing as my blog post.

      I have not tried OpenShift Enterprise v3 for on-prem deployment, but v3 is not yet available to OpenShift Online users.

      Do you know when OpenShift 3 will become available as the OpenShift Online offering?



  1. Dynamic clustering (auto scaling) in WebSphere, WebLogic, JBoss and Tomcat | WhyWebSphere Blog
  2. WebSphere Liberty autoscale clustering with Docker – IBM Advantage Blog

Leave a Reply

Please log in using one of these methods to post your comment: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: