What is the main purpose and sense to have staging server the same as production?

Question

Hi,

In our company we have staging and production servers. I'm trying to have them in state 1:1 after latest release. We've got web application running on several host and many instances of it.

The issue is that I am an advocate of having the same architecture (structure) of web applications on staging and production servers to easily test new features and avoid creating of new bugs with new releases.

But not everyone agree with me, and for them is not a such big deal to have different connection between staging application instances. Even maybe to have more application and connections between application on staging than on production server.

I would like to ask about pros and cons of such an approach? I mean some good points to agree with me, or some bad why maybe i don't have right. Some examples of consequences and so forth.

Answer 1

If your staging server is substantially different from your production server, then successful deployment and testing on the staging server does not tell you much about whether the world will come down crashing on you when you finally deploy to the production server.

I do not see any real advantage to your colleagues' preferred chaotic situation, to compensate for this obvious disadvantage. What do they claim they gain by letting the staging server's configuration get totally out of sync with that of the production server...?!

Answer 2

Staging is like the dress rehearsal of deployment. If you're not wearing the same costume you will be wearing on the night, how do you know it's going to fit, or you're not going to trip over the dangly bits.

More formally, you try to keep the staging environment as close as possible to the production environment in order to minimize differences which may cause or hide issues in the deployment. Note that I say "close as possible", since it's not always possible to have the same model of disk, or the same network interconnects, but you try to minimize those things that you can within the resources you have available.

Answer 3

I would go with "as close as possible" approach as well, as ptomli suggested... and that's mostly due to cost factor. If it is a farm that contains 5 servers, I would never recommend the staging to be just 1 stand alone server. This helps in scenarios where network layer is involved as well. If there are patches that affect network connectivity due to any reason (like security!) a single box staging server might not reflect the "real affect" of patching.

Answer 4

Martin Fowler recently blogged about having identical environments that could be cut over from one to the other, so your staging environment becomes your production environment after testing. He says:

One of the challenges with automating deployment is the cut-over itself, taking software from the final stage of testing to live production. You usually need to do this quickly in order to minimize downtime. The blue-green deployment approach does this by ensuring you have two production environments, as identical as possible. At any time one of them, let's say blue for the example, is live. As you prepare a new release of your software you do your final stage of testing in the green environment. Once the software is working in the green environment, you switch the router so that all incoming requests go to the green environment - the blue one is now idle.

I think an approach like this would be a great alternative to the seemingly chaotic environment you have today. Good luck convincing your team!