While talking to a customer a few weeks ago, they mentioned that they used Contained Availability Groups (CAG) everywhere. They also said they were amazing and wondered why everyone wasn't using them in other environments. Of course, I questioned the "everywhere", which turned out to be more of a default for new systems than a standard across all systems. That's likely true of most things since it's rare we get to update/patch/set something across an environment of any size and ensure every system is the same.
Still, setting a CAG as a default makes some sense for enterprises. This ensures that in an HA situation I have my logins, jobs, etc. already on a secondary node. That's been one of the challenges of using lightly linked systems that only sync up database level information. Log shipping, Replication, Availability Groups can all work to keep a secondary ready to take over, but they all miss information that is stored in master or msdb.
That's the stuff we have to sync manually. It can be done, but it's work. We've had numerous articles at SQL Server Central on syncing logins and other objects outside of your database.
Today I wonder how many of you are using CAGs in your environment? As the default for new systems? Moving all ones to this setup?
Or do you even know about them? They are relatively new, since SQL Server 2022, and I have to admit I've heard relatively little about them in the community or from customers. Many people use Availability Groups, but not many seem to use Contained Availability Groups.
Maybe another question is would you want to use them? There are a few things you have to consider and they can be slightly tricky, but they do some reduce some of the work when you have failovers. Of course, like any other technology, you need to test that your failovers work and you understand the ins and outs of how they work, just in case that switch isn't as smooth as you expect.
It should be, but sometimes things break. If they do, you want to ensure you, or someone on your staff, knows how to fix them.
