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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Inizia con il flusso di rinnovo dei certificati CPVM e VNC descritto nell'issue, quindi esamina la pull request collegata #7015 e la discussione recente. Riproduci il caso di un certificato scaduto su CloudStack 4.18 con KVM e Ubuntu 22.04; il lavoro è completato quando un certificato rinnovato viene applicato alle VM in esecuzione senza arrestarle, avviarle o migrarle.

Scritto dal modello di indicizzazione a partire dal testo della issue.