Analyzing the root cause of a Kubernetes cluster node in a "not ready" state involves investigating various aspects of the node's configuration and environment. Here are the steps you can follow to analyze the root cause:

1.Verify node status: Use the kubectl command-line tool to check the status of the node. Run kubectl get nodes to list all nodes in the cluster and their statuses. Ensure that the node is indeed reporting as "NotReady."
2.Check node conditions: Retrieve detailed information about the node's conditions by running kubectl describe node . Look for conditions such as "Ready," "OutOfDisk," "MemoryPressure," or "DiskPressure." Pay attention to any conditions that are not in a healthy state, as they can provide clues about the root cause.
3.Examine node events: Run kubectl get events --field-selector involvedObject.kind=Node --field-selector involvedObject.name= to view events specific to the node. Events may reveal any recent errors, warnings, or changes related to the node that could help identify the root cause.
4.Check kubelet logs: The kubelet is responsible for managing the node and its containers. Access the kubelet logs on the node itself to investigate any errors or warnings. The log file location varies based on the distribution or installation method. Common locations include /var/log/kubelet.log or /var/log/pods///.log.
5.Inspect resource utilization: Evaluate the resource utilization of the node, such as CPU, memory, and disk usage. High resource consumption or constraints can cause the node to become not ready. Use monitoring tools like Prometheus, Grafana, or the Kubernetes Dashboard to gather resource utilization metrics.
6.Check network connectivity: Ensure that the node has proper network connectivity. Verify that it can communicate with the control plane and other nodes in the cluster. Check firewall rules, network configurations, and DNS resolution to rule out network-related issues.
given the process you provide, I have some information about this not ready node:
1. the state of etcd service of this node is 0;
2. the state of crio service of this node is 0;
3. the memory usage of this node is above 85%;
4. the CPU usage of this node is above 90%;
the root cause of this event is (only tell me the cause not how you analyse):