This topic provides a high-level description of how Migrate for Anthos moves your existing VMs from VMware on-premises or AWS into containers on GKE.
Migrate for Anthos components
Migrate for Anthos contains a number of components split into three logical tiers:
The Infrastructure tier handles storage abstraction and management during streaming and at rest. This tier includes:
- An installation of Velostrata,
- The Migrate for Anthos Container Storage Interface (CSI) driver,
- Configuration applied to Kubernetes Nodes,
- Configuration applied to User Space and Runtimes on the source VM, and
- Other Migrate for Anthos controllers.
The Workload tier runs your migrated applications in GKE.
The Service tier is responsible for providing you visibility of your Migrate for Anthos components through logs and telemetry.
Understanding your migrated system containers
Migrate for Anthos converts and transforms migrated VMs into system containers on GKE. You don't need to pre-build container images during migration; Migrate for Anthos moves the workload automatically to a Kubernetes Persistent Volume (PV). Initially, the PV is streamed from VMware by the Migrate for Anthos Container Storage Interface (CSI) driver. When you are ready to complete the migration, you can export storage volumes to any provider supported by GKE.
Migrate for Anthos uses a wrapper image to create containers from your VMs. As part of functionality in the Migrate for Anthos beta, this image:
- Replaces the VM's operating system kernel with one supported by GKE.
- Configures the container's network interfaces, DNS, console output, logging and health status to use GKE services.
- Examines the volumes attached to the VM, locates the root partition and
fstabfor the file-system layout. Migrate for Anthos then mounts a PV from the source VM using the Migrate for Anthos streaming CSI driver.
- Run the applications and services from the VM's user-space
(for example, those launched by SysV-style or
systemdinit scripts) within the container.
VMware to GKE migrations
Migrations from VMware are configured in YAML files and orchestrated from GKE. Once GKE creates the containers for workloads, they start up quickly and stream storage as needed from on-premises. A local cache will store the data that copied from VMware to GCP.
Compute Engine to GKE migrations
Migrations from Compute Engine to GKE are also orchestrated from GKE, but with fewer dependencies on existing infrastructure. During migrations to GKE, Migrate for Anthos copies storage first and then starts up a container running your workload.