Understanding and Transitioning to NetScaler Flexed Licensing

NetScaler Flexed licensing is a new licensing framework designed to simplify license management. This blog post will discuss the critical aspects of Flexed licensing, how to transition from Perpetual or Pooled licensing to Flexed licensing, and the consequences of license file expiration.

What is Flexed Licensing?

Flexed licensing is a licensing model for Citrix NetScaler products that provides a pool of licenses that can be allocated to different NetScaler instances as needed. Your Flexed license includes software instance licenses and bandwidth capacity licenses. You apply the Flexed license on the NetScaler Console server or NetScaler Console on-prem. You must have either the NetScaler Console installed or deploy a NetScaler Console Agent that is accessible from the NetScalers you are going to license. The built-in agent will not suffice. You can only have one licensing agent per site. If you have multiple sites, you can either provide access from site to site and use the same licensing agent, or you can install one agent per site to be the licensing agent. The NetScaler Console Service currently only shows one instance of Agent as being the LSA. This is incorrect. Any of your agents can be currently running the LSA, and only one will show as being the LSA. Your instances will still communicate with the LSA on the agent.

Flexed licensing allows for flexible resource allocation across various NetScaler form factors deployed in the cloud or on-premises. It offers a way to maximize bandwidth utilization by enabling you to allocate the required bandwidth to each instance without overprovisioning. You can adjust the allocated bandwidth at runtime without disrupting traffic flow. Customers who purchased Universal Hybrid Multi-Cloud (UHMC) or Platform Licenses from Citrix are entitled to Flex Licenses for NetScaler.

Flexed Licensing Components

Zero-Capacity Hardware

Under Flexed licensing, NetScaler MPX and SDX instances are termed “zero-capacity hardware.” These instances require a Z-cap license to utilize bandwidth from the pool. This license is installed using the hardware serial number or the license access code. Once installed, it is locked to the hardware and cannot be shared on demand.

Standalone Instances

Unlike zero-capacity hardware, standalone instances like VPX, CPX, and BLX do not require a Z-cap license. Instead, they must check out bandwidth and an instance license from the pool to process traffic.

Bandwidth Pool

The bandwidth pool represents the total bandwidth available for all NetScaler instances, including physical and virtual ones. It typically consists of a pool for the Premium software edition, but it can also include Standard and Advanced editions if you transition from Pooled to Flexed licensing. For customers with a UHMC license, this pool will be limited to one terabit of throughput, while customers on a Platform License have unlimited bandwidth.

Instance Pool

The instance pool contains software instance licenses categorized by type: VPX/CPX/BLX, MPX, SDX, and VPX FIPS. Checking out a license unlocks the instance’s resources, including CPUs, SSL cores, packets per second, and bandwidth. Customers with both the UHMC and Platform License have unlimited instances for use with CPX, VPX, and BLX instances.

Migrating from Perpetual or Pooled Licensing to Flexed Licensing

Before your current license expires, you must transition to Flexed licensing. A maintenance window will most likely be necessary during the transition because a license reconfiguration and a NetScaler reboot are involved.

Transitioning from Pooled Bandwidth to Flexed

The following steps are common for VPX, MPX, and SDX:

1. Upload and apply Flexed software licenses on the NetScaler Console server.
2. If you have a Z-cap software license on NetScaler hardware (MPX/SDX) for a specific period, apply the Z-cap license received with Flexed.

For VPX/MPX:

• If you have a Pooled Premium bandwidth license, it will automatically convert to Flexed upon expiry. In this instance, a warm reboot to change licensing is not required.
• If you have a Pooled Standard or Advanced bandwidth license, manually check out Premium bandwidth and perform a warm reboot of the NetScaler instance.

For SDX:

1. Ensure that you switch to Flexed licensing before your current license expires.
2. Check out the necessary instance and bandwidth license from the Flexed license to SDX.
3. If all VPXs on SDX use the Premium edition, the license will automatically switch to Flexed after the old license expires. In this instance, a warm reboot to change licensing is not required.
4. Change the edition to Premium for VPXs with the Standard or Advanced edition. These VPXs will automatically reboot.
5. Reduce the Standard and Advanced bandwidth capacity on SDX to zero.

Transitioning from Pooled vCPU to Flexed Bandwidth Capacity (for VPX)

1. Upload and apply the Flexed software licenses on NetScaler Console.
2. Remove the existing license server using the NetScaler GUI, rendering NetScaler unlicensed until all steps are completed.
3. Add the license server with the Flexed/Pooled option.
4. Check out the required instance and bandwidth licenses for the NetScaler instance.
5. Perform a warm reboot of the NetScaler instance.

Transitioning from Fixed Subscription or Perpetual to Flexed

The following steps are common for VPX, MPX, and SDX:

1. Onboard to NetScaler Console.
2. Upload and apply Flexed software licenses on NetScaler Console.
3. Apply the Z-cap software license on NetScaler hardware (MPX/SDX).

For VPX/MPX:

1. Check out the required instance and bandwidth licenses to NetScaler.
2. Perform a warm reboot of NetScaler.
3. Delete the Fixed subscription license after NetScaler reboots.

For SDX:

1. Check out the required instance and bandwidth license from the Flexed license on SDX.
2. SDX reboot is not required if all VPXs on SDX are running the premium edition.
3. If a VPX is running the advanced or standard edition, switch it to the premium edition, which will automatically trigger a reboot of the VPX.
4. Apply the Z-cap software license on NetScaler SDX.
5. Check out the required instance and bandwidth license from Flexed licensing on SDX.
6. Delete the Fixed subscription license after NetScaler reboots.

Transitioning from CICO (Check-in/Check-out) to Flexed (for VPX)

1. Upload and apply Flexed software licenses on the NetScaler Console.
2. Using the NetScaler GUI, remove the existing license server. Note that NetScaler will be unlicensed until all steps are completed.
3. Add the license server with the Flexed/Pooled option.
4. Check out the required instance and bandwidth licenses for the NetScaler instance.
5. Warm reboot NetScaler.

Consequences of License File Expiration

License Expiration Scenarios

Before Term Expiration:

• If a new license is uploaded to the NetScaler Console server before the current license expires, two capacity pools (old and new) become available.
• The NetScaler instance will automatically switch to the new Flexed license after the old license expires.
• No restart or manual capacity reconfiguration is required.

After Term Expiration:

• The existing capacity pool expires.
• The NetScaler instance may continue to run licensed until it is restarted.
• If the instance restarts without a valid license file, it becomes unlicensed, potentially resulting in reduced functionality or complete shutdown.
• If the instance remains online and the new license is picked up, manual reconfiguration (capacity reassignment) might be necessary.

Connectivity Issues:

• If connectivity between the NetScaler instance and the NetScaler Console on-prem server is disrupted, the instance enters a 30-day grace period.
• During the grace period, licensing functionality continues normally.
• On the 31st day, VPX, CPX, BLX, and MPX instances undergo a forced reboot and become unlicensed.
• The throughput on all VPXs on SDX is reduced to 1 Mbps, making them unusable.

Summary Table

Best Practices

• Monitor License Expiration Dates: Regularly check the expiry information to ensure your licenses remain valid.
• Configure Notifications: Set up email or SMS notifications for upcoming license expirations to avoid disruptions.
• Maintain Connectivity: To prevent licensing issues, ensure consistent connectivity between the NetScaler instances and the license server.

By understanding the concepts of Flexed licensing and following the outlined transition steps, you can streamline license management and ensure the uninterrupted operation of your NetScaler infrastructure.

Links:

https://docs.netscaler.com/en-us/netscaler-application-delivery-management-software/current-release/license-server/adm-as-a-global-license-server.html

https://docs.netscaler.com/en-us/netscaler-application-delivery-management-software/current-release/licensing.html

https://docs.netscaler.com/en-us/netscaler-application-delivery-management-software/current-release/license-server/license-management.html

https://docs.netscaler.com/en-us/netscaler-application-delivery-management-software/current-release/license-server/scenario-license-expiry.html