Can we make Liferay dynamically scale in a private cloud?

Question

We have some VMware product for virtualisation in our data center (don't know details yet) and want to be able to scale Liferay in cases the assigned resources of the VM aren't enough. There seem to be the following options to do something like that. Please correct me if something is wrong or missing.

Option 1:

Liferay itself says it can be clustered. Multiple instances will communicate and synchronize so that it looks like one server to the user. Is it possible to add/remove such instances without interception of service?

Option 2:

Scaleing the underlying Application Server (Tomcat, Glassfish, JBoss, ...) seems nicer, but currently I only found Redhats OpenShift for doing this. How would that integrate in a private virtualisation environment? Are there other possibilites to scale said servers?

Other Options:

I've read about other cloud solutions in general, like Eucalyptus, OpenStack etc. but don't know if those could help here in any way.

Any suggestions or experience would be nice. Thanks

Answer 1

Option 1 works - check the documentation for how to set up clustering.

Option 2 depends on your environment etc., so that I don't feel like I can give a definitive answer for this one.

Answer 2

I have done this on an Openstack Cloud

2 Liferay appservers (tomcat) behind a Load Balancer provided by Openstack, the VIP is assigned by a floating IP and use that as your Liferay's entry point.

2 MySQL DB servers (master+master setup) behind a Load Balancer provided by Openstack, the VIP is then your MySQL DB IP you setup on your Liferay server.

It works like a charm. If you want a more resilient/reliable DB Cluster, you can do a Galera+DB setup.