There is a lot of discussion going on currently around OSS business models. The general consensus is that support contracts / professional services / support do not monetize well enough to grow a large business.

Hosted services is a viable business model. The risk here is to ensure that your product, if successful, cannot simply be deployed by Amazon. Dual licensing has been one response to the Amazon risk.

Admin tools alone are also thought to be difficult to monetize at sufficient value to grow a large business.

While DataStax has a nice UI, they have built a data platform with Cassandra the core, much like Cloudera has built a data platform with HDFS/HBase at the core. Personally, I view the data platforms as prepackaged and productized SI (which is very valuable..

Honestly, this is a very fine line to balance. If you open source your core technology, a lot of those "services" you listed are open to competition from other companies with little to no barrier to entry.