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	Node Restrictions	Check whether the node is available. Check whether the node OS supports the upgrade. Check whether the node is marked with unexpected node pool labels. Check whether the Kubernetes node name is the same as the ECS name.
2	Upgrade Management	Check whether the target cluster is under upgrade management.
3	Add-ons	Check whether the add-on status is normal. Check whether the add-on supports the target version.
4	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.
5	SSH Connectivity of Master Nodes	Check whether your master nodes can be accessed using SSH.
6	Security Groups	Check whether the Protocol & Port of the worker node security groups is set to ICMP: All and whether the security group with the source IP address set to the master node security group is deleted.
7	Arm Node Restrictions	Check whether the cluster contains Arm nodes.
8	Residual Nodes	Check whether nodes need to be migrated.
9	Discarded Kubernetes Resources	Check whether there are discarded resources in the clusters.
10	Compatibility Risks	Read the version compatibility differences and ensure that they are not affected. The patch upgrade does not involve version compatibility differences.
11	CCE Agent Versions	Check whether cce-agent on the current node is of the latest version.
12	Node CPU Usage	Check whether the node's CPU usage is above 90%.
13	CRDs	Check whether the key CRD packageversions.version.cce.io of the cluster is deleted. Check whether the cluster key CRD network-attachment-definitions.k8s.cni.cncf.io is deleted.
14	Node Disks	Check whether the key data disks on the node meet the upgrade requirements. Check whether the /tmp directory has 500 MB available space.
15	Node DNS	Check whether the DNS configuration of the current node can resolve the OBS address. Check whether the current node can access the OBS address of the storage upgrade component package.
16	Node Key Directory File Permissions	Check whether the owner and owner group of the files in the /var/paas directory used by the CCE are both paas.
17	kubelet	Check whether the kubelet on the node is running properly.
18	Node Memory	Check whether the node's memory usage is above 90%.
19	Node Clock Synchronization Server	Check whether the clock synchronization server ntpd or chronyd of the node is running properly.
20	Node OS	Check whether the OS kernel version of the node is supported by CCE.
21	Node CPU Cores	Check and make sure that the master nodes in your cluster have more than 2 CPU cores.
22	Node Python Commands	Check whether the Python commands are available on a node.
23	ASM Version	Check whether ASM is used by the cluster. Check whether the current ASM version supports the target cluster version.
24	Node Readiness	Check whether the nodes in the cluster are ready.
25	Node journald	Check whether journald of a node is normal.
26	containerd.sock	Check whether the containerd.sock file is on the node. This file affects the startup of container runtime in the Euler OS.
27	Internal Error	This check item is not typical and implies that an internal error was found during the pre-upgrade check.
28	Node Mount Points	Check whether there are inaccessible mount points on the node.
29	Kubernetes Node Taints	Check whether the taint needed for cluster upgrade exists on the node.
30	Everest Restrictions	Check whether there are any compatibility restrictions on the current Everest add-on.
31	cce-hpa-controller Limitations	Check whether there are compatibility limitations between the current and target cce-controller-hpa add-on versions.
32	Enhanced CPU Policies	Check whether the current cluster version and the target version support enhanced CPU policy.
33	Health of Worker Node Components	Check whether the container runtime and network components on the worker nodes are healthy.
34	Health of Master Node Components	Check whether cluster components such as the Kubernetes component, container runtime component, and network component are running properly before the upgrade.
35	Memory Resource Limit of Kubernetes Components	Check whether the resources of Kubernetes components, such as etcd and kube-controller-manager, exceed the upper limit.
36	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.
37	IPv6 Support in CCE Turbo Clusters	If IPv6 is enabled for a CCE Turbo cluster, check whether the target cluster version supports IPv6.
38	NetworkManager	Check whether NetworkManager of a node is normal.
39	Node ID File	Check the ID file format.
40	Node Configuration Consistency	When you upgrade a cluster to v1.19 or later, the system checks whether the following configuration files have been modified on the backend:
41	Node Configuration File	Check whether the configuration files of key components exist on the node.
42	CoreDNS Configuration Consistency	Check whether the current CoreDNS key configuration Corefile is different from the Helm release record. The difference may be overwritten during the add-on upgrade, affecting domain name resolution in the cluster.