3.11. Reflection Checkpoint

Key Takeaways

Before proceeding, ensure you can:

• Select the correct OS installation method (GUI, scripted, PXE, imaging) for a given scale/scenario requirement
• Explain why sysprep is required before deploying Windows VMs from a clone, and what breaks without it
• Choose GPT vs. MBR and the correct file system (ext4, NTFS, VMFS, ReFS, ZFS) for a given scenario
• Diagnose an APIPA address (169.254.x.x) as a DHCP failure, not a physical connectivity failure
• Distinguish active-active from active-passive clustering, and explain the heartbeat's role in failover
• Select NAS vs. SAN based on whether file-level or block-level access is required
• Identify the correct scripting tool (PowerShell, bash, batch) for a given OS environment
• Match licensing models (per-core, per-socket, per-concurrent user) to common enterprise software scenarios

Connecting Forward

Phase 4 applies security and protection to everything built in Phase 3. Every server role you've configured needs to be hardened. Every user account needs access controls. Every data store needs encryption and backup. The high-availability clusters you just designed need disaster recovery counterparts. Phase 4 is where the "what could go wrong?" question gets answered operationally.

Self-Check Questions

1. A company needs to deploy 50 Windows Server VMs from a single VM image. The servers must join the domain and receive unique computer names automatically. List the steps in order: (a) install OS in a VM, (b) sysprep the VM, (c) create a template, (d) deploy from template, (e) bootstrap script runs and joins domain. Is this the correct order? What happens if step (b) is skipped?

2. A clustered application fails over from Node A to Node B correctly during a simulated test, but during a real network outage, both nodes simultaneously claim to be active and begin writing to shared storage. What is this condition called, and what mechanism should have prevented it?