Pre-upgrade Check

The system automatically checks a cluster before its upgrade. If the cluster does not meet the pre-upgrade check conditions, the upgrade cannot continue. To avoid risks, you can perform pre-upgrade check according to the check items and solutions described in this section.

**Table 1** Check items
No.	Check Item	Description
1	Upgrade Management	Check whether the target cluster is under upgrade management.
2	Add-ons	Check whether the add-on status is normal. Check whether the add-on support the target version.
3	Helm Charts	Check whether the current HelmRelease record contains discarded Kubernetes APIs that are not supported by the target cluster version. If yes, the Helm chart may be unavailable after the upgrade.
4	SSH Connectivity of Master Nodes	Check whether your master nodes can be accessed using SSH.
5	Discarded Kubernetes Resources	Check whether there are discarded resources in the cluster.
6	cce-hpa-controller Limitations	Check whether there are compatibility limitations between the current and target cce-controller-hpa add-on versions.
7	Discarded Kubernetes APIs	The system scans the audit logs of the past day to check whether the user calls the deprecated APIs of the target Kubernetes version. NOTE: Due to the limited time range of audit logs, this check item is only an auxiliary method. APIs to be deprecated may have been used in the cluster, but their usage is not included in the audit logs of the past day. Check the API usage carefully.
8	HTTPS Load Balancer Certificate Consistency	Check whether the certificate used by an HTTPS load balancer has been modified on ELB.