In January Microsoft announced via e-mail good changes to Build & Release Private Agents. They introduced the concept of "Private Pipelines" in Visual Studio Team Services.
What are Agents?
An agent is basically a task-runner that you can pass build activities to, such as PowerShell scripts, executables, etc. The agent can either be Hosted (in the cloud on Azure) or on-premise (installed on your private servers).
When you run a build/release process from VSTS, it sends your tasks to an Agent to do your work.
The concept of a "pipeline" is introduced, which is essentially the number of concurrent agents running tasks at the same time. Previously, you were allowed one on-premise agent (for free) and if you wanted more agents on different servers you had to buy additional ones ($15/ea).
Now, you can have unlimited on-premise agents! You are given one private and hosted pipeline free with your VSTS account. So this means you can still only run operations on one agent at a time unless you buy additional pipelines.
Why is this a good thing?
If you have Dev/Test/Prod systems, you may want to place an agent on each machine where each has certain privileges and setup your build processes to communicate with each agent. And you may have no need for many concurrent build/release operations, but you want to have your agents (task runners) on different machines. This is VERY convenient. Previously, the work around was to just figure out ways to have your agent run on a single machine and execute operations remotely to the other machines, which you can imagine is a hassle.
Here is the full contents of the email:
Starting later this month and running through the end of February, we will be gradually deploying a change to how we count Build & Release Private Pipelines (previously called Private Agents) in Visual Studio Team Services. It does not change your bill.
Up to this point, you have needed a Private Pipeline for each separate private build agent or private release agent that you configure in your Team Services account.
Going forward, you can configure as many private agents as needed in your Team Services account without incurring extra charges. You'll only need as many Private Pipelines as the number of concurrent builds you want to run or releases you want to deploy using your own machines. With this new way of counting Private Pipelines you may be able to purchase fewer Private Pipelines than you do today.
Learn more about the impact of this change on your builds and releases.
If you have any questions, please contact us through the Visual Studio Developer Community (http://developercommunity.visualstudio.com) or via customer support (https://www.visualstudio.com/team-services/support/).