Migrating Services Across Clusters of Different Versions

Application Scenarios

This section describes how to migrate services from a cluster of an earlier version to a cluster of a later version in CCE.

This operation is applicable when a cross-version cluster upgrade is required (for example, upgrade from v1.7.* or v1.9.* to 1.17.*) and new clusters can be created for service migration.

Prerequisites

**Table 1** Checklist before migration
Category	Description
Cluster	NodeIP-related: Check whether node IP addresses (including EIPs) of the cluster before the migration have been used in other configurations or whitelists.
Workloads	Record the number of workloads for post-migration check.
Storage	Check whether the storage resources in use are provisioned by the cloud or by your organization. Change the automatically created storage to the existing storage in the new cluster.
O&M	Private configuration: Check whether kernel parameters or system data have been configured on nodes in the cluster.

Procedure

Create a CCE cluster.
Create a cluster with the same specifications and configurations as the cluster of the earlier version. For details, see Buying a CCE Cluster.
Add a node.
Add nodes with the same specifications and manual configuration items. For details, see Buying a Node.
Create a storage volume in the new cluster.
Use an existing storage volume to create a PVC in the new cluster. The PVC name remains unchanged. For details, see PersistentVolumeClaims (PVCs).

Storage switching supports only OBS buckets, SFS file systems, and shared EVS disks. If a non-shared EVS disk is used, you need to suspend the workloads in the old cluster to switch the storage resources. As a result, services will be interrupted.
Create a workload in the new cluster.
The workload name and specifications remain unchanged. For details about how to create a workload, see Creating a Deployment or Creating a StatefulSet. For details about how to mount a storage volume to the workload, see Creating a Pod Mounted with an EVS Volume.
Create a Service in the new cluster.
The Service name and specifications remain unchanged. For details about how to create a Service, see Services.
Commission services.
After all resources are created, commission the containerized services. If the commissioning is successful, migrate the services to the new cluster.
Delete or unsubscribe from the old cluster.
When all functions of the new cluster are stable, unsubscribe from or delete the old cluster. For details about how to delete a cluster, see Deleting a Cluster (Pay-per-Use).