MMT architecture¶

The Mirantis Migration Tool is designed to work with MSR-based source registries.

The mmt command syntax is as follows:

mmt <command> <command-mode> --storage-mode <storage-mode> ... <directory>

The <command> argument represents the particular stage of the migration process:

Migration stage	Description
verify	Verification of the MSR source system configuration. The verify command must be run on the source MSR system. Refer to Verify the source system configuration for more information. Applies only to migrations that originate from MSR 2.9.x systems.
estimate	Estimation of the number of images and the amount of metadata to migrate. The estimate command must be run on the source MSR system. Refer to Estimate the migration for more information. Applies only to migrations that originate from MSR 2.9.x systems.
extract	Extraction of metadata, storage configuration, and blob storage in the case of the `copy` storage mode, from the source registry. The extract command must be run on the source MSR system. Refer to Extract the data for more information.
transform	Transformation of metadata from the source registry for use with the target MSR system. The transform command must be run on the target MSR system. Refer to Transform the data extract for more information. Applies only to migrations that originate from MSR 2.9.x systems.
restore	Restoration of transformed metadata, storage configuration, and blob storage in the case of the `copy` storage mode, is made onto the target MSR environment. The restore command must be run on the target MSR system. Refer to Restore the data extract for more information.

The <command-mode> argument indicates the mode in which the command is to run specific to the source or target registry. msr and msr3 are currently the only accepted values, as MMT currently only supports the migration of MSR registries.

The --storage-mode flag and its accompanying <storage-mode> argument indicate the storage mode to use in migrating the registry blob storage.

Storage mode	Description
`inplace`	The binary image data remains in its original location. The target MSR system must be configured to use the same external storage as the source MSR system. Refer to Configure external storage for more information. Important Due to its ability to handle large amounts of data, Mirantis recommends the use of `inplace` storage mode for most migration scenarios.
`copy`	The binary image data is copied from the source system to a local directory on the workstation that is running MMT. This mode allows movement from one storage location to another. It is especially useful in air-gapped environments.

Storage mode

Description

inplace

The binary image data remains in its original location.

The target MSR system must be configured to use the same external storage as the source MSR system. Refer to Configure external storage for more information.

Important

Due to its ability to handle large amounts of data, Mirantis recommends the use of inplace storage mode for most migration scenarios.

copy

The binary image data is copied from the source system to a local directory on the workstation that is running MMT. This mode allows movement from one storage location to another. It is especially useful in air-gapped environments.

The <directory> argument is used to share state across each command. The resulting directory is typically the destination for the data that is extracted from the source registry, which then serves as the source for the extracted data in subsequent commands.