Microsoft Certified: DevOps Engineer ExpertDesign and implement source controlMedium
A company uses Azure DevOps for its source control, build, and release pipelines. They have several build agents running on virtual machines in an on-premises data center. The IT department has a strict policy that requires all virtual machine operating systems to be patched and restarted monthly. This causes build agent downtime during patching. The development team wants to minimize this downtime and ensure that build capacity is always available, even during maintenance windows. Which type of build agent should they implement?
- ASelf-hosted agents within an Azure Virtual Machine Scale Set
- BSelf-hosted agents with a manual update process
- CMicrosoft-hosted agents
- DContainerized self-hosted agents
Show answer & explanationAnswer & explanation
Correct answer: A. Self-hosted agents within an Azure Virtual Machine Scale Set
Self-hosted agents within an Azure Virtual Machine Scale Set (VMSS) provide elastic scaling and automatic agent lifecycle management. When VMs are patched or updated, new instances can be spun up automatically, ensuring continuous agent availability and minimizing downtime during maintenance. This directly addresses the need for continuous availability despite monthly patching.
Why the other options are wrong
- B. Manual updates would still lead to downtime and do not provide automatic scaling or high availability during maintenance.
- C. Microsoft-hosted agents are not suitable as the requirement specifies agents in an on-premises data center.
- D. Containerized agents can help with environment consistency but do not inherently solve the underlying VM patching downtime problem without a scale set or similar orchestration.
Azure DevOps Scale Set Agents
Self-hosted agents deployed in an Azure Virtual Machine Scale Set, offering automatic scaling, lifecycle management, and high availability for build and release pipelines.
- Automatically scales agent count based on demand.
- VM instances can be automatically re-imaged or replaced.
- Reduces administrative overhead for agent management.
- Ensures continuous build capacity during maintenance.
Memory trick: Scale sets keep agents afloat, even during storms.