Migration refers to the process of transferring Virtual Machines and their associated resources from a VMware environment to an OpenStack environment. It involves multiple steps, including planning (creating a Migration Plan), discovery (fetching VM resource information), and the actual migration execution. During migration, users provide details such as migration name, and description, select VMs, map networks, map volume types, and configure specific parameters for each VM. The goal is to seamlessly move VM workloads while preserving their configurations and ensuring compatibility with the target OpenStack environment. Successful migration results in VMs running efficiently within the OpenStack infrastructure.


Check the prerequisites before initiating the migrations.

Once the VMs of the Migration Plan are discovered ( Discover VMs ), the user can initiate the migration.

Trilio provides 3 types of migrations and the user can choose as per their need, more details can be found here.

  1. Dry-run Migration:

    • Create VMs on OpenStack with attached storage volumes, networking, and security groups for testing purposes while migrating the VM snapshot data from VMware.

  2. Cold Migration:

    • Shut down VMware virtual machines and then migrate them to OpenStack. This process can take minutes to hours and may cause significant downtime, making it more disruptive.

  3. Warm Migration:

    • Leverage VMware snapshots and the Change Block Tracking feature to migrate VMs with minimal disruption. Take snapshots, copy changed blocks, and then repeat the process after shutting down the VMs. The downtime can be significantly lower than that of a Cold Migration.

While initiating the migration, the user needs to provide a few more below-mentioned information to ensure a seamless migration of the VMs.


To perform the actual migration, users need to:

  • Provide a name and description for the migration.

  • Choose the type of migration from a drop-down menu.

Network Mapping

During migration, users can:

  • Map-enabled networks in Guest VMs to OpenStack Networks.

  • Trilio automatically detects networks, providing a seamless mapping experience.

Volume Types Mapping

Users need to:

  • Map Datastores detected from the migration plan VMs with OpenStack volume types.

  • This ensures proper mapping of storage resources during migration.

VM Selection

Users must:

  • Select VMs mapped to the Migration Plan for migration.

  • For each VM, choose the correct flavor and Availability Zone.

  • Specify configurations for disks to be created on OpenStack.

  • For the VMs that are UEFI booted, a glance image must be selected. Refer to this page for more details.

There are certain limitations that have to be taken care of by the user once the migration is successful, please refer to the Limitations page for more information.


Deletion of the initiated Migrations can be done to clean up the unnecessary entries in the list. Please note that deleting a migration does not clean up the migrated VMs or their associated resources from OpenStack. The user will have to explicitly remove the migrated resources if necessary.\

How-to Guide: Initiating a Migration

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