Neither OSGi nor Spring were designed to address issues such as high availability, clustering, or load balancing. Of course, you could create a clustered and load-balanced system using Spring and OSGi, but you probably need something else, like a way to detect and transmit node errors and load levels.
Since you are building a web application, most likely you will be using one of many application servers. Good AS products provide clustering for you. Some also provide load balancing. You can also achieve load balancing through fully independent configuration yourself, using Apache, for example, to work with the main application servers.
, JGroups, . , JGroups.
, , Ehcache, .