In this post we will talk about the value and the importance of deployments scripts and what a deployment script should contains where we are working with a cloud environments (in our case Azure).
A deployment script(s) is a collection of scripts that are used to deploy a solution (in one or multiple environments). In general, deployments scripts are reused between different deployments of the same solutions, the only thing that we need to configure is the custom configuration for that environment (naming, custom folders path, connection strings and so on).
A deployment script that serves a cloud application is no very different from a deployment script used for on-premises systems. Sometimes there are small things that are forgotten or ignored for the deployments scripts that serve a cloud application.
This happens because we forget that each Azure resource is like an external dependency that should be treated separately.Visual Studio Deployment
With the latest version of Visual Studio (VS2015), deployment can be made easily directly from Visual Studio (VS). To tell you the true sometimes is a pleasure to be able to deploy and manage Azure application directly from the IDE.
When we deploy our application directly from VS we are assuming that people that will make the deployments will have VS installed. Not all IT and people involved in operational and support team will have the IDE installed.
Not only this, but we limit ourselves to manual deployment only. All the deployments will be possible only when by a manual trigger. This means that we will not be able to deploy automatically our Azure application during a night build for example.
Even if the development team can use Visual Studio to deploy a web application or content to a worker roles, we should have all the time deployment scripts that are able to make a full deployment.Subscription and subscription administrator account
We should never assume that we will do all the time a deployment to the same subscription. Even if at the beginning we have the same subscription for all the environments, in time it is pretty clear that we will not end up with only one Azure subscription.
In this context we should be able to control and specify what subscription is used when a deployment is done. You should never assume that the subscription administrator account already logged in the Power Shell with his Azure credentials. We should be able to configure this information when we make a deployment. It is not necessary to do this directly in a configuration file, at least we should provide this information as parameters of the deployment script.
This is extremely important when we have a night build for example. The night build should be able to make a full deployment of an Azure application, without assuming that specific resources were already created for him.Azure resources around the application
Usually an Azure application doesn’t contains only one Azure Service. Multiple Azure Services are used by an application
Another assumption that is usually made is related to Azure resources that are required by an Azure application. We are assuming that resources like storage (Azure Blob Storage) or the Azure Cache is already created.
In general this is almost true. But what is happening if we need to create a new environment or something happens and we need to recreate that resources
In that case we would need to manually create that resource. Once we create that resource, we need to configure our application to point to our resource (path, connection string, and authentication and authorization stings.
The vision of a capabilities of a deployment script (for cloud):
- To create all resources that are needed to run the cloud application
- To configure all the services that form our cloud application
- To be run from command line
- To be able to create and deploy fully our cloud application without human intervention
- Based on our needs, priorities and availability of people the vision can become the reality of only a dream
- The most important thing is to aspire to the vision