A development team is implementing a strategy for managing build agents. They require agents that are automatically scaled up or down based on demand, ensuring that build queues remain short during peak times and resources are not wasted during off-peak hours. The agents must run on Linux and be able to execute Docker commands. Which type of build agent infrastructure should they implement?
- ASelf-hosted agents deployed on individual Azure VMs.
- BAgent pools configured with Azure Virtual Machine Scale Sets.
- CContainerized agents running as Azure Container Instances.
- DMicrosoft-hosted agents with custom Docker configurations.
Show answer & explanationAnswer & explanation
Correct answer: B. Agent pools configured with Azure Virtual Machine Scale Sets.
Azure Virtual Machine Scale Sets (VMSS) integrated with Azure DevOps agent pools provide automatic scaling of self-hosted agents. This ensures that agents are dynamically provisioned and de-provisioned based on demand, optimizing costs and build queue times, while allowing for custom configurations like Linux and Docker capabilities.
Why the other options are wrong
- A. Individual Azure VMs for self-hosted agents do not provide automatic scaling capabilities without significant custom scripting.
- C. Containerized agents on Azure Container Instances (ACI) can be used, but VMSS offers a more robust and integrated solution for a fleet of dynamically scaling build agents, especially for longer-running or more resource-intensive builds than ACI might typically handle.
- D. Microsoft-hosted agents cannot be customized with specific Docker configurations or guarantee Linux environments for all builds, and they don't scale based on your specific demand in the same way.
Azure DevOps Scale Set Agents
Self-hosted build agents that are managed by an Azure Virtual Machine Scale Set, enabling automatic scaling (up and down) based on the demand from build and release pipelines.
- Provides dynamic agent capacity, optimizing costs and queue times.
- Allows for custom environments (OS, software, Docker).
- Integrated with Azure DevOps agent pools for seamless management.
Memory trick: Think of Scale Set Agents as a smart, elastic factory floor: it automatically adds or removes workers (agents) and tools (Docker) based on how many orders (builds) come in, so you're never overstaffed or understaffed.