#Pre-Upgrade Preparation

#Important notes before upgrade

• Supported platform versions for upgrade: 3.16.0, 3.16.1, 3.16.2, 3.18.0, 3.18.1. Ensure your current platform version is within this supported range before upgrading.

• The Kubernetes version of all clusters in the platform must be at least 1.28. If any cluster is below this version, upgrade its Kubernetes version first.

• If the platform has a cluster with a service mesh provided by the platform, ensure that its Istio version is 1.20 or higher. Otherwise, upgrade the service mesh before proceeding.

• Check whether any cluster in the platform has the CostManager or Kubecost plugins installed. These plugins are deprecated in version 4.0 and must be uninstalled prior to upgrading.

• If your platform version is 3.16 and any cluster has the ClickHouse log storage plugin installed, uninstall it before the upgrade. After the upgrade is complete, reinstall the plugin.

• Ensure that the /cpaas/minio directory on the control plane nodes of the global cluster has at least 120 GB of available space. If not, expand the storage before proceeding.

• During the upgrade, the upgrade package must be copied to any control plane node in the global cluster and extracted. If the upgrade package and extraction path are on the same disk, ensure the disk has at least 250 GB of free space.

• When upgrading the cluster's Kubernetes version to 1.31 or higher, all running Pods will be restarted. This behavior is due to changes in the PodSpec fields introduced in Kubernetes 1.31 and cannot be avoided. For more details, refer to the Kubernetes issue report: #129385.

• Starting from version 4.0, the upgrade process for clusters using the global DR (Disaster Recovery) solution has changed. Please refer to global DR procedure for the new procedure.

#Preparation procedure