Tech Brief: Citrix Image Portability Service

Overview

Hybrid multi-cloud image management is a challenge many Citrix administrators face because it is complicated. Several platforms, tools, and complex workflows are trying to solve the challenge of hybrid multi-cloud image management. This image management challenge creates a situation where these tools and complex workflows don’t fit well, and many are vendor-specific. For Citrix administrators, it is challenging to map the right tools to the proper purpose. Citrix developed the Citrix Image Portability Service to simplify the challenge and make it one tool for all things Citrix and all the use cases you have delivering virtual desktops and applications. Citrix Image Portability Service provides Citrix administrators with a simple workflow to manage workloads between on-premises and public cloud platforms. Developed using App Layering cross-platform technology, the Citrix Image Portability Service uses Citrix DaaS Rest APIs to migrate on-premises Machine Creation or Provisioning Services images to either Microsoft Azure, Google Cloud Platform (GCP), or AWS (AWS).

The Citrix Image Portability Service provides Citrix administrators with three primary business values:

1. Migration from on-premises to public cloud - Simplified migration of existing on-premises images to public cloud resource locations, such as Azure and Google Cloud. Create or update an image in one location and seamlessly deploy it to multiple platforms.
2. Business Continuity - Cloud architecture allows organizations to deploy and scale for unplanned events rapidly. No need for procurement and hardware delivery delays. Citrix infrastructure can scale for user numbers in real time.
3. Image Maintenance - Simplifies the management of images across platforms, making it easy to manage images between on-premises and cloud resource locations from a single location.

Use Cases

The Citrix Image Portability Service focuses currently focuses on a single use case and the challenges in managing images on multiple platforms.

On-Premises to Public Cloud

The Image Portability Service simplifies image management between on-premises and public cloud migrations. When resource capacity demands reach 100%, overflow traffic can be directed to the public cloud resource location. Known as “Cloud Bursting,” the Image Portability Service to stage virtual machine instances ensures that the cloud resource location images are prepared and ready to receive users as needed. The Image Portability Service can also pre-stage public cloud resource locations in a Disaster Recovery need.

Image Portability Architecture

The Citrix Image Portability Service is a REST API with all the semantics and requirements of other Citrix DaaS and Virtual Apps and Desktops APIs. The headers and authentication work the same as the other Citrix APIs do. Detailed information on how to use these REST APIs can be found here.

Citrix Image Portability Service also relies on the Connector Appliance for Cloud Services to communicate with Citrix Cloud. Image Portability Service uses provisioning technology to create and manages resources in the resource locations where the Connector Appliance is installed. The Image Portability Services sends commands to the appliance to complete the export or prepare jobs. These commands, the provisioning operations, and the binary bits that make up the worker are relayed through the Connector Appliances. The responses forwarded back to the cloud also go through the Connector Appliance. There is no direct interaction with the Connector Appliance, as all operations are transparent within the workflow.

A Windows (SMB) file share must be locally accessible to any export job. For MCS, the share is the target for disks copied from the vSphere data store. For PVS, the shared folder contains the vDisks to be uploaded.

The Citrix Image Portability composting engine is Citrix App Layering technology capable of being deployed on-demand in a specific hypervisor or public cloud. The engine attaches to disks to apply changes and to composite images from multiple layers (disks). During the Image Portability Service export stage, the source disk is converted from standard (VHD/VHDx) format as it is written to the local SMB file share. During the preparation stage, the composite engine attaches to the input disk to apply changes to the image to make it operational in the target platform.

In addition to the Connector Appliance, the following components are required as part of the Image Portability Architecture:

• A valid Citrix Cloud Customer ID and Citrix DaaS entitlement
• On-premises master Machine Create Services (MCS) or Provisioning Services (PVS) image
• Access to public cloud resource location

Image Migration Workflow

Migrating images with the Citrix Image Portability Service consists of a 4-stage workflow.

1. Export: The export stage exports images from the on-premises hypervisor and preps them for upload to the public cloud resource location. This stage can include converting file system types to a common format for the cloud.
2. Upload: The upload stage uploads the image to the target cloud subscription. This process is a point-to-point transfer using the configuration and credentials for the public cloud supplied by the administrator.
3. Prepare: The prepare stage is a complex set of steps wherein the source platform components are removed, and the target platform components are injected into the image. The VDA is also automatically reconfigured and rearmed based on the supplied configuration properties. At the end of this phase, the image boots once to allow Windows plug-and-play to run and configure the OS for the new platform. Once the preparation completes, the image is ready to be provisioned with MCS.
4. Publish: The final stage deploys the image as a new machine catalog. This step may or may not involve the Image Portability Service directly. In the case of MCS, the Citrix Virtual Apps and Desktops Remote PowerShell SDK can automate the creation of an MCS catalog from the migrated disk. In the case of PVS on Azure or Google Cloud, the Image Portability Service provides a REST interface and for example, PowerShell, to publish the migrated disk directly into the PVS vDisk store.

Throughout the four stages, the Image Portability Service uses App Layering compositing engines in the background to modify the image and drive the process.

All Citrix Image Portability workflows are based on the configuration of the source image and provisioning targets, either MCS or PVS. The workflow chosen determines the steps required by the Image Portability Service. The following table outlines the jobs that are necessary for each of the supported Image Portability workflows:

*The original image is a PVS vDisk and does not require export out of the source platform hypervisor

Summary

Hybrid multi-cloud image management is challenging and complicated. Citrix Image Portability provides a simple workflow to manage workloads between on-premises and public cloud resource locations.

Further reading: Learn more about the Citrix Image Portability Service in our Technical documentation.