Agent VMs that keep DRS, HA and similar services of a cluster running while vCenter is down. They are deprecated as of version 9.0, with retreat mode now the recommended alternative.
Also called vSphere Cluster Services.
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In the Ultra Transcenders books
Each book explains vCLS in context, with comparison tables and the common traps.
Terms in this definition
- Agent
A specialised form of Microsoft Copilot set up for one particular job, pairing instructions with knowledge and skills. You can create one in Copilot Studio, SharePoint or Agent Builder, and administrators control them from the Microsoft 365 admin center.
- Virtual machines
Infrastructure-as-a-service compute giving complete control of the operating system, making it a fit for lift-and-shift moves and for software relying on OS-level pieces like COM.
- DRS
The Default Rule Set, Microsoft's managed WAF rules that succeed OWASP CRS and defend against XSS, SQL injection and other frequent attacks. Single rules may be overridden or switched off.
- vCenter
Management software for VMs, clusters and ESX hosts. Each domain in VCF gets a dedicated one.
- retreat mode
Switches vSphere Cluster Services (vCLS) off for a cluster, rather than relocating vCLS VMs ahead of datastore maintenance. As of vCenter 9.0, which deprecates vCLS, it is the recommended approach, and HA and DRS carry on unaffected.