Manual rollback of an application / service

Question

I have a Service Fabric application with a few services underneath it. They are all currently sitting at version 1.0.0.

I deploy an update out to the cluster for version 2.0.0. Everything is running fine and the deployment succeeds. I notice a very large but in the version. Is there a way to manually rollback to version 1.0.0? The only thing I have found is automatic rollback during an upgrade.

Answer 1

Matt's answer is correct, but I'll elaborate a bit on it here.

The key is in understanding the different steps during application deployment:

• Copy
• Register
• Create
• Upgrade

Visual Studio rolls these up into single "publish" and "upgrade" operations to make it easy and convenient. But these are actually individual commands in the Service Fabric management API (through PowerShell, C# or HTTP). Let's take a quick look at what these steps are:

Copy: This just takes your compiled application package and copies it up to the cluster. No big deal.

Register: This is the important step in your case. Register basically tells the cluster that it can now create instances of your application. Most importantly, you can register multiple versions of the same application. At this point, your applications aren't running yet.

Create: This is where instances of your registered applications are created and start running.

Before we get to upgrade, let's look at what's on your cluster. The first time you go through this deployment process with version 1.0.0 of your application (call it FooType), you'll have just that one type registered:

FooType 1.0.0

Now you're ready to upgrade. You first copy your new application package with a new version (2.0.0) up to the cluster. Then, you register the new version of your application. Now you have two versions of that type registered:

FooType 1.0.0

FooType 2.0.0

Then when you run the upgrade command, Service Fabric takes your instance of 1.0.0 and upgrades it to 2.0.0. If you need to roll it back once the upgrade is complete, you simply use the same upgrade command to "upgrade" the application instance from 2.0.0 back to 1.0.0. You can do this because 1.0.0 is still registered in the cluster. Note that the version numbers are in fact not meaningful to Service Fabric other than that they are different strings. I can use "orange" and "banana" as my version strings if I want.

So the key here is that when you do a "publish" from Visual Studio to upgrade your application, it's doing all of these steps: it's copying, registering, and upgrading. In your case, you don't actually want to re-register 1.0.0 because it's already registered on the cluster. You just want to issue the upgrade command again.

For an even longer explanation, see: Blue/Green Deployments with Azure ServiceFabric

Answer 2

Just follow the same upgrade procedure, but targeting your 1.0.0 version instead. "Rollback" is just an "upgrade" to your older version.