Staging model for intsances - How many instances needed and recommended by serviceNow

[Andrew Yasser]

Hello All, 

I was asking about which is the most practical and optimum number of instances needed as a staging instances before PROD and after DEV.

I have 3 models seen so far:

Model one: having DEV, then TEST (for testers), then UAT (for business), and PROD

Model two: having DEV, then UAT (for testers then after confirmation business to test), then PREPROD, then finally PROD

Model three: having DEV, then TEST, then UAT, then PREPROD, then finally PROD

All models will have Sand-Box.

If I'm in the choice of having only one instance either TEST or PREPROD, what do you recommend to leave and why ?

Thanks in Advance.

[Dr Atul G- LNG]

Hi @Andrew Yasser 

As per best practice

dev - Test - Prod

if you want can pick up 

Model one: having DEV, then TEST (for testers), then UAT (for business), and PROD

just remember, more instances, more maintenance / upgrade / clone and deployments. 

[Andrew Yasser]

Hello @Dr Atul G- LNG 

can you please indicate, why not model 2 ? From my POV preprod allows reproducing the batches before deploying it  on production to decrease production issues.

and also can you please clarify why not having testers and business testing on same instance and handing over to each other the testing by JIRA issue assignee ?

[Dr Atul G- LNG]

Hi @Andrew Yasser 

Model two: having DEV, then UAT (for testers then after confirmation business to test), then PREPROD, then finally PROD

So if we see this 2 : Sand box - Dev - UAT - Preprod -prod

It is not a good practice to ask tester and business to test in same environment, Will you clone before business start testing? 

2nd pre pord is, yes it is good to see any issues in deployment but can  we follow same approach in UAT? deployment in preprod , and then again need a round of testing , which will assure for prod. 

• Also more instance will delay the deployment in prod and can cause many issues , also need to create multiple pipelines if plan to start / use devOps. 

[s4scott]

The most common use of four environments I've seen is:
TRAIN - used as a sandbox for training, pre-upgrade planning, testing of plug-ins - This environment can be cloned over as needed
DEV - Dev environment is cloned from PROD on a schedule in alignment with QA to ensure development is done against Prod equivalent code
QA - Quality assurance environment is where code ready for user testing is validated prior to promotion to Prod
PROD - Production

It can be really helpful to have a TRAIN environment that can be upgraded early for testing/evaluation, and where you can install plugins to test they work as expected, knowing that operationally the data in TRAIN can be cloned over at any time since it is not used for active development or UAT.