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Table Of Contents
Table 31. Certificate Modes for ESXi Hosts
Certificate Mode Description
VMware Certificate Authority (default) Use this mode if VMCA provisions all ESXi hosts, either as the
top-level CA or as an intermediate CA.
By default, VMCA provisions ESXi hosts with certificates.
In this mode, you can refresh and renew certificates from the
vSphere Web Client.
Custom Certificate Authority Use this mode if you want to use only custom certificates that
are signed by a third-party or enterprise CA.
In this mode, you are responsible for managing the certificates.
You cannot refresh and renew certificates from the
vSphere Web Client.
Note Unless you change the certificate mode to Custom
Certificate Authority, VMCA might replace custom certificates,
for example, when you select Renew in the vSphere Web Client.
Thumbprint Mode vSphere 5.5 used thumbprint mode, and this mode is still
available as a fallback option for vSphere 6.x. In this mode,
vCenter Server checks that the certificate is formatted correctly,
but does not check the validity of the certificate. Even expired
certificates are accepted.
Do not use this mode unless you encounter problems that you
cannot resolve with one of the other two modes. Some vCenter
6.x and later services might not work correctly in thumbprint
mode.
Certificate Expiration
Starting with vSphere 6.0, you can view information about certificate expiration for certificates that are
signed by VMCA or a third-party CA in the vSphere Web Client. You can view the information for all hosts
that are managed by a vCenter Server or for individual hosts. A yellow alarm is raised if the certificate is
in the Expiring Shortly state (less than eight months). A red alarm is raised if the certificate is in the
Expiration Imminent state (less than two months).
ESXi Provisioning and VMCA
When you boot an ESXi host from installation media, the host initially has an autogenerated certificate.
When the host is added to the vCenter Server system, it is provisioned with a certificate that is signed by
VMCA as the root CA.
The process is similar for hosts that are provisioned with Auto Deploy. However, because those hosts do
not store any state, the signed certificate is stored by the Auto Deploy server in its local certificate store.
The certificate is reused during subsequent boots of the ESXi hosts. An Auto Deploy server is part of any
embedded deployment or vCenter Server system.
If VMCA is not available when an Auto Deploy host boots the first time, the host first attempts to connect.
If the host cannot connect, it cycles through shutdown and reboot until VMCA becomes available and the
host can be provisioned with a signed certificate.
vSphere Security
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