Help! I cannot complete my Pull Request in TFS!

A quick one today: if the Complete button is greyed out in your Pull Request UI, ask your TFS Administrator to start the TFS Job Agent.

The TFS Job Agent does many things – including handling Pull Requests completion.

Successfully handle disruptive changes with no downtime: the TFS 2015 example

It is something I’ve mentioned a few years ago but the question came out again during my presentation at x-celerate.de:

How should I handle a breaking change without service interruptions?

This is a brilliant question, and the best example I can give out is the TFS 2015 Upgrade that introduced support for renaming Team Projects.

If you don’t want to have downtime for your users the only mitigation is to introduce an intermediate migration layer which is going to be pouring data from the production stack and transform it into what you want.

The upside of this is that you are performing a very expensive and time-consuming operation out-of-band, so you can apply all the usual patterns for highly available application deployments.

The downside is that it is a costly operation, it could be compute, storage or something else but it will cost something out of it.

In my specific case I was able to perform a scheduled upgrade into the mandatory weekend window (yes, there was still a bit of downtime but it was due to the nature of the product and it was expected – you can overcome the hurdle if you are building your own product though) instead of having days of downtime due to the migration of data from a schema to another, at the cost of lots of storage space for the temporary tables and a dedicated server to run the tool.

Re-release to an environment, don’t spin up a whole new deployment!

I know this happens on a regular basis – but it caught up my eye this morning as I am finishing up preparation for X-Celerate.de.

Let’s say your Release fails:

What many do is to actually spin up a whole new instance of the Release itself. While this works ok, you are missing out on something important: traceability.

In a sea of releases, with microservices and multiple moving pieces, how would you be able to trace back what happened during that failed release?

Why don’t you actually try to re-deploy the same failed bits instead?

Doing this provides you all the details about the previous failures, and it is going to be much easier to recall in case you might need to refer to the scenario in the future.

Oh in case you were wondering… it was all about my lab’s DNS server, which cached the Kudu website of an App Service I was deploying as 404 but it is Sunday after all…

If you don’t package your stuff you are doing it wrong!

Packages are a thing, exactly like containers are.

I mean – who wants to spend countless time in moving files, editing configuration files and the likes? Nobody, I know, but still so many people don’t take advantage of application packaging when it comes to deploying stuff!

Let’s take an average web application as an example. What is the reason that pushes you to actually move stuff from a certain folder (DLLs, .configs, etc.) to the target server, instead of packaging your application’s components and move these instead?

All you need to do is adding /p:DeployOnBuild=true /p:WebPublishMethod=Package /p:PackageAsSingleFile=true to the MSBuild Arguments if you are using a traditional Build task.

If you are using .NET Core you just need to select the Zip Published Projects in the Publish task!

I just love the MSDeploy comeback. I am a huge supporter of this technology, because it makes life so much easier. It also has the side effect of enabling deployment to Azure in a snap, as it is one of the three supported delivery methods!

Let’s say you have a Build Definition and a Release Pipeline for this application. You want to deploy it to Azure – this is what you need to do:

What if you want to run the same application (providing it actually works on-premise as well and it does not specifically require any technology not available in your datacentre) on your own servers?

Firstly you’ll need to create a Deployment Group in VSTS – this can be done either by statically running the appropriate PowerShell script on your machines (interactively, via RDP) or dynamically with a bit of PowerShell or Azure if you are using IaaS. It is required because IaaS/on-premise machines in a Deployment Group will run an agent.

Then you can run whatever script you need to install the pre-requisites your application requires and configure all the settings, and eventually you can use the IIS Web App tasks to interact with IIS. Focusing on the IIS Web App Deploy task…

That Package is exactly the same package I used in the Azure deployment above. So you can easily have a Continuous Delivery pipeline on Azure and a different one (with the same cadence or a different one, your call) for on-premise, both starting from the same artifacts.

Containers are better – of course – but they require a minimum or ramp up or learning in order to actually implement them in a production environment. Moving to MSDeploy on the other hand is a matter of minutes at most, and it will provide a tangible improvement.