A lot of things are possible in the cloud, but not everything. A couple of technologies in particular that might seem common in on premise systems are nearly impossible to deploy in the cloud.
The first is the idea of multiple networks. Many systems are deployed around the idea that there is a common, “public” network (like a corporate intranet) to which all servers and workstations are connected, as well as a private network used to connect related servers specifically for administrative purposes or to provide a specific type of connectivity for your software. The cluster interconnect network for Oracle Real Application Cluster (RAC) would be an example of this type of secondary network. For a variety of reasons, most of which revolve around security of the cloud service as a whole, no commercial cloud service providers allow for the creation of private, isolated network segments at this time.
The second problematic technology when planning a cloud migration is multicast networking. Multicast networking allows data packets to be sent from one source to multiple recipients in a single transmission. It is often used in media streaming and high availability or resource sharing software. Examples of this again include Oracle RAC, as well as Apache Tomcat’s native clustering feature, both of which require multicast capabilities to coordinate resource, data, and node availability between servers in the cluster.
If your system requires the use of private and/or multicast networking, you may have to consider a redesign of any dependent features before migrating to the cloud.
What about FlashGrid®?
While researching cloud migration alternatives you may run across mention of FlashGrid®, which allows for the creation of pseudo private networks and shared storage. It is used to create RAC interconnect networks and shared file storage for ASM in environments that might not otherwise support it, like the Cloud. Amazon advertises the use of this software to create RAC systems in their EC2 environment, and there are tutorials on how to deploy it in Azure as well.
The catch is that Amazon and Azure don’t actually provide or support FlashGrid software themselves. They simply provide instructions describing how to set it up for yourself, and expect you to get support directly from FlashGrid. This is a perfect example of the difference between what is technically possible and what is allowed for US Government organizations like DOD.
Oracle has made it perfectly clear that they will not certify or support a commercial Cloud technology stack from any provider that includes software not directly supported by that provider. In the paper Oracle Real Application Clusters (RAC) Support on Third Party Clouds, which has been updated to include versions as recent as Oracle 18c, it states the following:
“FlashGrid® is not supported to enable shared storage for Oracle RAC on Third-Party Clouds” and “the lack of natively provided shared storage in addition to certain network restrictions that would need to be worked around on most Third-Party Clouds currently prevent Oracle from supporting any Third-Party Cloud for Oracle RAC presently and regardless of technical feasibility.”
This means that it is literally not possible to legitimately license Oracle RAC in any commercial cloud environment, including Cloud One, which is based in Amazon and Azure. While a commercial corporation may be willing to risk rolling the dice with their licensing, the Department of Defense can do no such thing. The Database and Application Development STIGs require that all software be fully licensed and supported by the vendor, which makes commercial Cloud deployment of Oracle RAC effectively illegal, except to Oracle’s own cloud environment.