At the beginning, Microsoft announced on June 15, that as Windows 10, Windows Server would now have the same releases cycle to provide customers innovation via latest operating system capabilities.

Innovations areas focused on SDDC technologies – Software Defined DataCenter, containers and microservices. Note that today, Insider Builds are available only in Windows Server Datacenter Core and Standard Core editions, so first configuration needs to be done via the well knowns Sconfig.cmd command and remote management.

Listed below, key points on Datacenter and Containers:

SDDC Cloud Host new features:

  • Security
    • Shielded Linux VM
    • SDN: Encrypted virtual networks
    • Secure clusters
    • SMB 1 disabled  by default
  • Resiliency and Availability
    • SDN: Reduced downtime for tenant connections through gateways
    • Spaces Direct: Scoped Spaces to mitigate impact of multi-node loss
    • Spaces Direct: Marginal drive handling for predictive detection of drive failures
  • Efficiency
    • Data Deduplication available for ReFS
    • New Data Deduplication DataPort API for optimized ingress/egress
    • Space efficiency with ReFS Compaction
    • Performant Spaces Direct Multi Resilient Volumes (MRV)
  • Hyper-converged Scale
    • Cluster Sets: Significantly increases hyper-converged SDDC cloud scale by grouping multiple clusters into a larger fabric
  • Hardware support
    • Support for Storage Class Memory (SCM) in Spaces Direct

Cloud Guest new features:

  • IIS
    • TLS info: administrators can make specific recommendations to default to HTTPS
  • Disaster Recovery
    • Storage Replica Test Failover
  • Guest + Host better together
    • vPMEM in Guest: Tenants can use and manage PMEM/SCM
    • Tenant-Aware VM Start Ordering: App Ready / OS Heartbeat for better load balancing
    • Guest RDMA
  • Improvement in time accuracy
  • Azure enlightened clusters – optimized to run on Azure IaaS

Developers and Containers new features:

  • New base container images (available on Windows Insider Docker Hub repo)
    • Optimized Nano Server base image (over 70% smaller)
      • The .NET team is providing an preview image based on Nano Server with .NET Core 2.0
      • The PowerShell team is providing a preview image based on PowerShell 6.0
    • Optimized Server Core base image (over 20% smaller)
  • Support for SMB volume mounting
  • Infrastructure for Orchestrators
    • Networking enhancements for on going Kubernetes work
    • Named pipe mapping support
  • Bug fixes, performance enhancements

What’s New in Build 16237 for Windows Server

Persistent Memory can now be exposed to Hyper-V VMs:

  • In this build, NTFS-formatted direct access volumes that are created on non-volatile DIMMs can now be exposed Hyper-V VMs. This enables Hyper-V VMs to leverage the low-latency performance benefits of Persistent Memory devices.
  • Virtualized Persistent Memory (vPMEM) is enabled by creating a VHD file (.vhdpmem) on a direct access volume on a host, adding a vPMEM Controller to a VM, and adding the created device (.vhdpmem) to a VM. Using vhdpmem files on direct access volumes on a host to back vPMEM enables allocation flexibility and leverages a familiar management model for adding disks to VMs.
  • PowerShell can be used for the creation and management of Virtualized Persistent Memory.

Battery Passthrough:

  • With new additions to Set-VM, a PowerShell cmdlet, you can now enable and disable Battery Passthrough, a new feature. Battery Passthrough let your VMs have the same battery state as the host they are on. To use this feature of Set-VM, use the flag -BatteryPassthroughEnabled {$true, $false}. This option is only available for version 8.2 virtual machines.

Improvements to Container Networking: 

  • This build introduces enhancements to container networking to better support Kubernetes by adding support for multiple containers (w/out Hyper-V isolation) to a single Pod (Network Compartment) as well as only requiring a single endpoint per Pod for all traffic types (e.g. ingress and East-West)
  • The Host Networking Service (HNS) now has support for creating ACL, NAT, and Load Balancing network policies for Container endpoints for fine-grained policy application.

RDMA for Trusted Guests:

  • This build includes several enhancements for (Trusted) Guest RDMA to enable low-latency storage access with zero CPU usage by Trusted Guest VMs – this is ideal for running Windows File Servers in a Guest to accelerate file serving. Requires updated NIC drivers.

Improvements to Software Defined Networking:

  • Encryption can be enabled for virtual network subnets to protect your traffic from anyone with physical access to the wire, including network administrators.
  • Failover time for SDN gateways is improved. Now, you will observe much faster failover times for the gateways, even with high number of connections.
  • Access control lists can be applied for infrastructure on logical subnets.

Improvements in Networking transports:

  • 2X throughput improvement for single connection TCP and UDP performance in low latency intra-datacenter scenarios
  • Default congestion control algorithm CUBIC for high speed networks

 Improvements in HTTP(s):

  • SSL throttling to enable predictable service for established connections, in the face of high incoming SSL traffic.
  • Deterministic certificate updates for HTTPS enabling greater service availability.

Improvements in time accuracy:

  • Pressing EU regulations in 2018 require strict time precision and traceability.  Win32tm improvements in RS3 support greater time accuracy, and jitter is removed from the measurements that calibrate the service.
  • New system event logging lets you archive time service data to support traceability compliance.
  • System center monitoring now includes a new rule which lets you detect when a machine in your environment is out of compliance.

Nano Server optimized for Containers:

  • Nano Server is now a container only option and optimized for containers, more information is available in the Delivering continuous innovation with Windows Server blog post.  To optimize for containers, several features were removed that were in the Nano Server base image in Windows Server 2016, these include WMI, PowerShell, .NET Core, and the Servicing stack, which has significantly reduced the image size.

Server Core base image optimizations:

  • The Windows Server Core base image has been optimized saving over 20% download and on disk space.

How to Download

The latest Windows Server build and matching symbols are available for download here. Matching Windows Server container images will be available via the Docker Hub. For more information about Windows Server containers and Insider builds, please visit


To install Insider Builds, the following keys are available for unlimited activations of Windows Server. These keys may be used throughout the pre-release cycle.

  • Server Datacenter Core: B69WH-PRNHK-BXVK3-P9XF7-XD84W
  • Server Standard Core: V6N4W-86M3X-J77X3-JF6XW-D9PRV

Stay tuned for next Windows Server Insider Builds,