VM console cannot access after VNC certificate expired

##### ISSUE TYPE

* Bug Report

##### COMPONENT NAME

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CPVM
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##### CLOUDSTACK VERSION

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4.18
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##### CONFIGURATION

advanced networking

##### OS / ENVIRONMENT

Hypervisro: KVM virtualization with ubuntu 22.04

##### SUMMARY

VM console cannot access after VNC certificate expired。
Default certificate valid for 1 year ，then automatically renews certificates when they expire by cloudstack。
I made sure the certificate was updated on the host，but Th running VM instances need stop and start to apply the new certificate or migraton to other host. For production environments, this is hard to do

I don't know how to get a new certificate to take effect without rebooting the vm

https://github.com/apache/cloudstack/pull/7015

##### STEPS TO REPRODUCE

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##### EXPECTED RESULTS

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Make a new certificate to take effect without rebooting the vm
Provide a setting to turn off tls for vnc
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##### ACTUAL RESULTS

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先从 issue 中描述的 CPVM 和 VNC 证书续期流程开始，然后查看链接的 pull request #7015 和最近的讨论。在使用 KVM 和 Ubuntu 22.04 的 CloudStack 4.18 上复现证书过期的情况；当续期后的证书能够应用于正在运行的 VM，且无需停止、启动或迁移这些 VM 时，即表示完成。

由索引模型根据 Issue 内容生成。