In today’s digital landscape, the deployment of Active Directory (AD) servers plays a pivotal role in managing identity, authentication, and access control within an organization. With businesses expanding globally, the need for a robust and scalable AD infrastructure across multiple regions becomes imperative. OCI offers a powerful platform for deploying AD servers, ensuring seamless operations across diverse geographical locations.
As a continuation from part one let’s delve into the best practices for implementing AD servers in OCI within and across multiple regions:
Understanding the Landscape
OCI spans many regions globally, offering diverse options for data centers. Each region has its distinct benefits, like compliance adherence, latency considerations, and disaster recovery capabilities. Identify which regions are essential for your AD infrastructure based on factors such as user distribution, compliance requirements, and latency concerns.
Network Architecture and Connectivity
Design a network architecture that ensures optimal connectivity within each region, between regions, and back to on-prem. Leverage regional private subnets to create private networks and FastConnect for secure hybrid communication with SLAs.
Use regions with multiple Availability Domains where possible for AD server placement, ensuring proper network segmentation for security and performance. For regions with one Availability Domain, take advantage of Fault Domains within the Availability Domain instead. Implement Security Lists or Network Security Groups (NSGs) to control traffic flow between subnets and regions, enhancing security.
Shared Service Design
Consider treating your AD servers as a shared service within OCI by placing the servers in a dedicated VCN not cohabited by other workload environments (Prod, QA, Dev). This provides enhanced benefits such as:
- Segregation of duties – Allow system admins to control and manage AD servers in one central location, while allowing the network admins to manage underlying OCI network resources.
- Simplified design – Seperate workload environments located in other VCNs such as Prod, QA and Dev can all access the same AD services from a singular location.
- Scalability – Additional VCNs can be added over time as business needs grow without the need to deploy new AD servers in each VCN created.
Security Best Practices
Security is paramount in a distributed AD environment. Implement a robust Identity and Access Management (IAM) strategy to control access to resources. Utilize OCI’s Identity and Access Management service to manage user access, permissions, and roles effectively.
Regularly update and patch AD servers to mitigate vulnerabilities. OCI’s automation capabilities, like Terraform or Resource Manager, can aid in automating patching processes across regions.
Performance Optimization
Optimize AD server performance by leveraging OCI’s compute options. Consider utilizing higher-performance compute instances for AD domain controllers to ensure efficient directory service operations. Operating systems function differently from each other when it comes to handling AD authentication tasks. For example, many flavors of Linux authenticates every key stroke from a client. Which adds input and output delay compared to a non-domained joined instance. Placing AD servers within the same region as your domain joined OCI resources will ensure low latenacy for authentication and authorization processes.
Treat each OCI region as its own AD site, add each VCN CIDR range to the appropriate Active Directory Sites and Services (ADSS) to ensure clients select the closest available AD server. Typically, AD servers function as the main DNS servers for clients as well. If this the case, configure the VCN DNS and DHCP options to use the regional AD servers for domain related DNS queries. This will ensure low latency DNS queries for resources deployed in OCI. Preventing these resources from inadvertently querying on-prem DNS servers directly across a private connection which brings higher latency.
Observability & Management
Utilize OCI’s monitoring and logging capabilities to gain insights into AD server performance and proactively identify and resolve bottlenecks or performance issues. Set up alerts and notifications in OCI to respond promptly to any anomalies.
Disaster Recovery Strategy
Establish a comprehensive disaster recovery (DR) plan by taking advantage of multiple OCI regions to mitigate potential data loss or service disruptions. Multi-region AD deployments provide a robust replication strategy using technologies like Active Directory Sites and Services (ADSS) to replicate directory data across regions.
Regularly test DR procedures to ensure seamless failover capabilities in case of region-wide outages or disasters. Utilize OCI’s regional resilience by deploying standby AD servers in alternate regions to maintain service continuity.
Conclusion
Deploying Active Directory servers across multiple regions in Oracle Cloud Infrastructure demands meticulous planning, robust architecture design, and adherence to security and performance best practices. By leveraging OCI’s diverse services and capabilities, organizations can achieve a resilient, secure, and high-performing distributed AD infrastructure that meets global business demands while ensuring data integrity, accessibility, and compliance across regions.