The main vSphere Lifecycle Manager operations are related to checking whether the objects in your environment are up to date with a vSphere Lifecycle Manager baseline or an image and updating or upgrading ESXi hosts.

Compliance check
An operation of scanning ESXi hosts to determine their level of compliance with a baseline attached to the cluster or with the image that the cluster uses. The compliance check does not alter the object.
An operation of applying software updates to the ESXi hosts in a cluster. During remediation, you install software on the hosts. Remediation makes a non-compliant host compliant with the baselines attached to the cluster or with the image for cluster.
Remediation Pre-Check
You perform a pre-check before remediation to ensure that the health of the cluster is good and that no issues occur during the remediation process.
When you stage patches or extensions to an ESXi host, you download patch and extension VIBs to the host without applying them immediately. Staging makes the patches and extensions available locally on the hosts. This action is available only for clusters managed by baselines or baseline groups.