A couple of days ago I mentioned some cutting over techniques.

Yesterday’s note (which didn’t go out due to a typo), looked at the the aspect of the physical cutover. Today looks at an alternate approach to transitioning services.

There are other approaches that I mentioned in the prior notes that can be taken to provide a more seamless transition. However these techniques will require at least three things to be in place:

  1. A TSA must be in place.
  2. A common entry point (think landing webpage) preferably with the new combined organization.
  3. The underlying data to be kept in sync.

This is definitely more complex setup, but if minimizing your downtime for the cutover is a hard requirement or ensuring a smooth user experience for your new customers/users is paramount, then maybe it is worthwhile to consider this.

What you will be building is a shared infrastructure that will last as long as the TSA is in effect, and must explicitly outline the terms (costs, personnel, SLAs, transition plans, etc).

With the TSA, you should have the beginnings of the plan for who will own which parts of the new common entry point. This can be a single network gateway or even common landing page. This is the common router for your end users directing them to the parts that have been conveyed, and those that are waiting to be conveyed. This is also the piece that will be implementing the transition layer, and provide the shim to migrate all of your services/apps/hardware to the new company.

Perhaps the biggest challenge, and what will dictate whether you can make use of the smoother transitions, is the data. While your apps can do stuff, the results have to be stored somewhere so it can be referenced later. In the case of transitions like the blue green model, you will be effectively running two copies of the service sourced from a single source of truth. Unless that single source of truth is kept consistent (syncing, replication, pooling), then wonky things can happen.

Of course this is all dependent on the goals of the acquisition, the applications, the requirements for conveyance, and how the data is stored which will dictate approaches.

cab