Entra Join: 40k Devices in 9 Months

Key insights

• Entra Join vs Active Directory
  They moved 40,000 devices from on‑premises Active Directory to cloud-native Entra Join in nine months, showing AD isn’t dead but shifting to a cloud-first model.
• Identity synchronization
  Start with identity synchronization (Cloud Sync or Entra Connect) to run on-prem and cloud in parallel and avoid a risky big‑bang cutover.
• Autopilot & Graph API
  Use Microsoft Intune, Autopilot and automation via the Graph API to speed device provisioning, self-service tasks and reduce manual work.
• Legacy application dependencies
  Plan for complex legacy apps by mapping dependencies, using app proxies or VMs when needed, and testing rollback paths before migration.
• Reduced attack surface
  Moving devices to Entra Join eliminates VPN dependence, shrinks the attack surface, and enforces compliance through cloud policies instead of relying on internal AD controls.
• Avoid co-management trap
  Prefer a clear migration path and use source‑of‑authority switching for users; don’t get stuck in long co‑management states—automate, measure velocity, and prioritize the new starter experience.

Video Overview: A Rapid Migration Story

In a recent YouTube episode by Merill Fernando, industry veterans Michael Brunker and Prem Kothandapani describe how an enterprise migrated almost 40,000 devices from on-premises Active Directory to cloud-native Entra Join in nine months. The conversation frames this achievement as both a technical feat and a strategic shift toward cloud-first identity and device management. Moreover, the speakers highlight real-world challenges and practical decisions, offering lessons that other organizations can evaluate against their own constraints.

Importantly, the video mixes high-level strategy with operational detail, so it serves as a useful case study rather than a marketing pitch. The hosts explain who did the work, how they organized the team, and which automation techniques accelerated the effort. Consequently, the story helps readers consider tradeoffs between speed, risk, and cost when planning similar migrations.

Why Move Away From Traditional Domain Join?

The presenters argue that moving to Microsoft Entra ID and cloud-first device join reduces reliance on corporate networks and VPNs, which they call the “VPN tax.” As a result, users can sign in and access resources anywhere, which better supports hybrid and remote work. At the same time, the move narrows the attack surface because devices no longer act as direct gateways into on-premises domain controllers.

However, the speakers caution that migration is not a universal cure for security or management headaches. For example, organizations trade some legacy tooling comfort, like Group Policy Objects, for modern controls through Intune and cloud policy engines. Therefore, teams must plan to replicate or rethink existing policies and configurations in the new environment.

Technical Tools and Approaches Explained

The episode covers the core components used in the migration, including identity synchronization with Entra Connect or Cloud Sync, onboarding devices to Entra Join, and modern deployment pipelines using Autopilot. Furthermore, the team automated many steps through the Microsoft Graph, and they built a custom self-service wipe application to streamline recoveries and device refreshes. These elements together created a repeatable blueprint for scaling across thousands of endpoints.

Moreover, the conversation highlights the value of a granular approach to identity authority. By using source-of-authority switching, administrators could convert individual users to cloud-managed identities without disrupting others. This flexibility allowed for an incremental migration rather than a high-risk, all-at-once cutover, which in turn reduced business impact while maintaining momentum.

Tradeoffs and Key Challenges

Legacy applications proved to be the toughest friction point during the migration, particularly those tightly coupled to on-premises authentication or network dependencies. As a result, the team had to choose between rehosting apps, refactoring authentication, or providing hybrid access for a transition period. Each option carried costs: rehosting adds infrastructure expense, refactoring demands development effort, and hybrid access prolongs operational complexity.

Another important tradeoff involved co-management. While co-management can ease the shift by running both traditional and modern management tools in parallel, the hosts urge caution to avoid becoming permanently dependent on both systems. Consequently, leaders should set clear exit criteria for legacy tools so teams do not get trapped in a long-term dual-management state that increases overhead.

Operational Lessons and Automation Gains

Operationally, the migration succeeded because the team standardized processes and invested in automation early. For example, automated provisioning with Autopilot and scripted actions via the Microsoft Graph reduced manual effort and made the onboarding experience consistent for users. In addition, a focused core team of 10–15 people guided the overall strategy while broader business units handled local change management.

Moreover, the hosts emphasize monitoring migration velocity and adjusting priorities when blockers appeared. They learned that small, frequent wins keep stakeholders engaged and that documenting fallback plans prevents surprises. Therefore, automation did not eliminate the need for careful governance; instead, it amplified the benefits of disciplined project management.

What Organizations Should Consider Next

For teams contemplating a similar move, the video suggests starting with an inventory of applications and dependencies, then piloting with low-risk user groups to refine workflows. Additionally, leaders should balance speed with safety by defining rollback points and security controls up front. This planning helps avoid rushed decisions that later create technical debt.

Finally, the story underscores that Entra Join migration is achievable but not inevitable for every organization at once; choices depend on legacy complexity, regulatory needs, and internal skills. Nevertheless, by understanding tradeoffs and investing in automation, many enterprises can make meaningful progress toward a cloud-native identity and device management posture.

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