This article explains the parameters used to set the thresholds which will help to adjust the threshold :
1. To adjust the number of days before the certificate expiry when the alarm is triggerred as warning
2. To adjust the number of days before the certificate expiry when alarm is triggerred as Critical.
3. To adjust the validity of certificate of esxi host which is replaced using VMCA.
VMware vCenter Server
VMware vSphere Esxi
Below parameters are available in vCenter server instance>configure>advanced settings
vpxd.cert.threshold - defines how many days in advance vCenter should trigger a certificate expiry warning, set the value in days.
vpxd.certmgmt.certs.hardThreshold - defines the number of days before certificate expiration when a critical alarm is triggered, set the value in days.
vpxd.certmgmt.certs.daysValid - defines how many days the new certificate will remain valid. set the value in days.