vCenter Server 6 Deployment Topologies and High Availability
vCenter Server 6 has some fundamental architectural changes compared to vCenter Server Server 5.5. The multitude of components that existed in vCenter Server 5.x has been consolidated in vCenter Server 6 to have only two components vCenter Management Server and Platform Services Controller, formerly vCenter Server Single Sign-On.
The Platform Services Controller (PSC) provides a set of common infrastructure services encompassing
- Single Sign-On (SSO)
- Certificate Authority
The vCenter Management Server consolidates all the other components such as Inventory Service & Web Client services along with its traditional management components. The vCenter Server components can be typically deployed in with either embedded or external PSC. Care should be taken to understand the critical differences between the two deployment models. Once deployed one cannot move from one mode to another in this version.
vCenter Server with Embedded PSC:
- Sufficient for most environments. Easiest to deploy and maintain
- Aimed at minimizing fault domains. Use in conjunction with only one of VMware Product or Solution.
- Multiple standalone instances supported
- Replication between embedded instances not supported
- Supports Windows & Appliance
Embedded mode vCenter Server 6
vCenter Server with External PSC:
- Recommend this if deploying/growing to multiple vCenter Server instances that need to be linked
- Reduces footprint by sharing Platform Services Controller across several vCenter Servers
- Deploy more than one PSC to provide resilience within the environment
- Supports Windows & Appliance
Available Options for vCenter Server failure protection
Backup (VDP / Third Party VADP):
Third Party Solutions that layer on top of VMware HA:
Platform Service Controller
vCenter Server High Availability:
USE CASES FOR THIS SOLUTION:
- This solution helps reduce downtime for maintenance operations, such as patching or upgrades, on one node in the cluster without taking down the vCenter Server database.
- Another potential benefit of this approach is that MSCS uses a type of “shared-nothing” cluster architecture. The cluster does not involve concurrent disk accesses from multiple nodes. In other words, the cluster does not require a distributed lock manager. MSCS clusters typically include only two nodes and they use a shared SCSI connection between the nodes. Only one server needs the disks at any given time, so no concurrent data access occurs. This sharing minimizes the impact if a node fails.
- Unlike the vSphere HA cluster option, the MSCS option works only for Windows virtual machines and does not support the vCenter Server Appliance.
- Before you can set up MSCS for vCenter Server availability, you must create a virtual machine with one of the following guest operating systems:
Additionally, you must add two RDM disks to this VM. These disks must be mounted and when they are added, you must create a separate SCSI controller with the bus sharing option set to physical. The RDM disks must also be independent and persistent.In this configuration all vCenter Server services can be protected individually. The backend Microsoft SQL database can also be protected separately with SQL Clustering.
- Windows 2008 SP2
- Windows 2012 R2 Datacenter
Deployment Modes for vCenter Server:
Local vCenter Server & PSX High Availability:
- This model protects the platform service controller service by having multiple instances of PSC locally behind a load balancer. Failure of a PSC does not impact the usage of the infrastructure. The PSCs should also be separated from each other physically using anti-affinity rules. The PSCs replicate state information vCenter Server nodes are individually clustered with WSFC for HA. The vCenter Servers interact with the PSCs through a load balancer.
Local vCenter and PSC high availability
Multiple Site vCenter Server and PSC basic Architecture:
Multiple Site vCenter Server & PSC with High Availability Architecture:
Multi-site vCenter Server and PSC high availability architecture