vSphere Datacenter Design for the Platform Services Controller
As of vSphere 6.0, vCenter Server installation and configuration has been dramatically simplified. This section talks about the decisions which need to be made to successfully deploy vCenter.
Understanding vCenter Components and Services
The installation of vCenter now consists of only two components that provide all services for the virtual data center. This is different from previous releases as each component needed to be installed individually. The two components are as follows:
- Platform Services Controller – provides infrastructure services for the data center. The Platform Services Controller contains the following services:
- VMware vCenter Single Sign-On™
- License Service
- Lookup Service
- VMware Directory Service
- VMware Certificate Authority (CA)
- vCenter Services – The vCenter Server group of services provides the remainder of the vCenter Server functionality. It includes the following services:
- vCenter Server
- VMware vSphere Web Client
- Inventory Service
- vSphere Auto Deploy
- VMware vSphere ESXi Dump Collector
- VMware vSphere Syslog Collector (Windows) / VMware Syslog Service (Appliance)
vCenter Deployment Modes
When deploying vCenter Server, you can use two basic architectures, vCenter Server with an Embedded Platform Services Controller or vCenter Sever with an External Platform Services Controller.
vCenter Server with an Embedded Platform Services Controller
This mode installs all services on the same virtual machine or physical server as vCenter Server. It is ideal for small environments or in cases where simplicity and reduced resource utilization are key design factors. The following figure shows this configuration.
Figure 1. Embedded Platform Services Controller
vCenter Server with an External Platform Services Controller
This mode installs the platform services on a separate system to the vCenter services. The platform services must be installed first. It is ideal for larger environments, if there are multiple vCenter Servers in the same site and where there is a need for single pane of glass in the environment. The following figure shows this configuration.
Figure 2. External Platform Services Controller
Choosing the right architecture to be used is critical, because once the model is chosen; it is difficult to change after the installation. In addition, configuration limits could limit the scalability of the environment.
Enhanced Linked Mode
In addition to the basic configurations this release includes Enhanced Linked Mode. The Platform Services Controller provides this feature, which uses the Lookup Service to be able to show a single pane of glass view of the environment. The recommended configuration when using enhanced linked mode is to use an external Platform Services Controller.
Note: Although using Enhanced linked mode with embedded Platform Services Controllers can technically be done, it is not a recommended configuration. See List of Recommended topologies for vSphere 6.0 (2108548) for further details.
In addition to this, the scalability maximums depend on the configuration on the environment, for more details; see the Scalability Maximums section below for some details on this.
The environment therefore should plan for the expected growth and the need for high availability. These factors will generally dictate the best configuration to be used for enhanced linked mode.
The following sections discuss the recommended and not recommended options for Enhanced Linked Mode configurations.
Enhanced Linked Mode with an External Platform Services Controller without HA (Recommended)
In this case the Platform Services Controller is configured on a separate virtual machine and then the vCenter Servers are then joined to that domain, providing the Enhanced Linked mode functionality.
The following figure shows this configuration.
Figure 3. Enhanced Linked Mode with an External Platform Service Controller Without HA
There are benefits and drawbacks to this approach:
Benefits
|
Drawbacks
|
|---|---|
Less resources consumed by the combined services
|
Network connectivity loss between vCenter and the Platform Service Controller can cause outages of the services
|
More vCenter instances are allowed
|
More Windows licenses required (if on a Windows Server)
|
Single-Pane of glass management of the environment
|
More Virtual Machines to manage
|
Outage on the Platform Services Controller will cause an outage for all vCenter Servers connected. High availability not included in this design
|
Enhanced Linked Mode with an External Platform Services Controller with HA (Recommended)
In this case the Platform Services Controllers are configured on separate virtual machines and configured behind a load balancer to provide high availability to the configuration. The vCenter Servers are then joined to that domain using the shared Load Balancer IP address, which provides the Enhanced Linked mode functionality, but is resilient to failures.
The following figure shows this configuration.
Figure 4. Enhanced Linked Mode with an External Platform Service Controllers in an HA Configuration
There are benefits and drawbacks to this approach.
Benefits
|
Drawbacks
|
|---|---|
Less resources consumed by the combined services
|
Network connectivity loss between vCenter and the Platform Service Controller can cause outages of the services
|
More vCenter instances are allowed
|
More Windows licenses required (if on a Windows Server)
|
Single-Pane of glass management of the environment
|
More Virtual Machines to manage
|
Platform Services Controller Configuration Highly Available
|
Enhanced Linked Mode with Embedded Platform Services Controllers (Not Recommended)
In this case vCenter is installed win an embedded configuration on the first server. Subsequent installations are then configured in embedded mode but joined to an existing Single Sign-On domain.
Linking embedded Platform Services Controllers is possible but it is not a recommended configuration. It is preferred to have an external configuration for the Platform Services Controller.
The following figure shows this configuration.
Figure 5. Enhanced Linked Mode with Embedded Platform Services Controllers
Combination Deployments (Not Recommended)
In this case, there is a combination of embedded and external Platform Services Controller architectures.
Linking an embedded Platform Services Controller and an external Platform Services Controller is possible but it is not a recommended configuration. It is preferred to have an external configuration for the Platform Services Controller.
The following figure shows this example scenario.
Figure 6. Enhanced Linked Mode in Combination Deployment
Enhanced Linked Mode using only an Embedded Platform Services Controller (Not Recommended)
In this case there is an embedded Platform Services Controller and vCenter Server linked with an external standalone vCenter Server.
Linking a second vCenter Server to an existing embedded vCenter Server and Platform Services Controller is possible but it is not a recommended configuration. It is preferred to have an external configuration for the platform Services Controller.
The following figure shows this example scenario.
Figure 7. External vCenter Linked to an Embedded Platform Services Controller
Mixed Platform vCenter for Windows vs. the vCenter Server Appliance
Prior to vSphere 6.0, there was no interoperability between vCenter for Windows and the vCenter Server Linux Appliance. With vSphere 6.0, they are functionally the same. With Enhanced Linked Mode, both versions of vCenter are interchangeable. This allows for vCenter for Windows and vCenter Server Appliance configurations to act as Platform Services Controllers or vCenter servers for the other platform. The following is an example mixed platform environment.
Figure 8. Mixed Platforms with vCenter
High Availability for the Platform Services Controller
As discussed in the enhanced linked mode section, providing high availability protection for the Platform Services Controller is one of the supported configurations. This task however does add an additional level of overhead to the configuration. The following sections describe how to protect the Platform Services Controller when in Embedded and External modes.
High Availability for an Embedded Platform Services Controller
When using an Embedded Platform Services Controller protection is provided in the same way that vCenter Server is protected. For more details see Section High Availability for vCenter Server
High Availability for an External Platform Services Controller
If high availability is required for an external Platform Services Controller, protection is provided by adding a secondary backup Platform Services Controller, and placing them both behind a load balancer.
The load balancer must support Multiple TCP Port Balancing, HTTPS Load Balancing, and Sticky Sessions. VMware has currently tested several load balancers including VMware NSX (Version 6.2 and above), F5 and Netscaler. Outside of VMware NSX, VMware does not directly support these products. See the vendor documentation regarding configuration details for any load balancer used.
For details on setting up with VMware NSX, Romain Decker, one of my awesome colleagues who does a lot with NSX, has done a pretty awesome blog on it:
https://blogs.vmware.com/consulting/2015/11/configuring-nsx-v-load-balancer-for-use-with-vsphere-platform-services-controller-psc-6-0.html
The following figure shows this example configuration, which uses a primary and a backup node.
Figure 9. High Availability for the Platform Services Controller
With vCenter 6.0, connectivity to the Platform Services Controller is stateful and the load balancer is used for its fail-over ability only. Thus it is not recommended to do active-active connectivity to both nodes at the same time or you risk corruption of the data between nodes.
High Availability for vCenter Server
Availability of the vCenter Server is critical due to the number of solutions requiring continuous connectivity, as well as to ensure that the environment can be managed at all times. Whether it is a standalone vCenter Server or if it is embedded with the Platform Services Controller, to avoid extended periods of downtime it should run in a highly available configuration.
Several methods can be used to provide higher availability for the vCenter Server system. The choice depends on maximum downtime tolerated, whether failover automation is required, and the budget available for software components.
The following table lists methods available for protecting the vCenter Server system and the vCenter Server Appliance.
Redundancy Method
|
Protects
vCenter Server system? |
Protects
vCenter Server Appliance? |
|---|---|---|
Automated protection using vSphere HA.
|
Yes
|
Yes
|
Manual configuration and manual failover. For example, using a cold standby.
|
Yes
|
Yes
|
Automated protection using Microsoft Clustering Services (MSCS)
|
Yes
|
No
|
Automated protection using vSphere Fault Tolerance.
Note: There could be significant performance impact to using vSphere Fault Tolerance to protect vCenter Server and the Platform Services Controller, depending on the activity in the environment. |
Yes
|
Yes
|
Scalability Maximums
Prior to deciding the configuration for vCenter the following are the scalability limitations for the different configurations. Be aware when you are designing a configuration that it can have a huge impact on the end design. The below table is current as of December 2015.
Scalability Item
|
Maximum
|
Number of Platform Services Controllers per Domain
|
8
|
Maximum PSCs per vSphere Site, behind a single load balancer
|
4
|
Maximum objects within a vSphere Domain (Users, Groups, Solution Users)
|
1,000,000
|
Maximum number of VMware Solutions connected to a single PSC
|
4
|
Maximum number of VMware Products/Solutions per vSphere Domain
|
10
|
Backup and Restore
In vSphere 6.0 GA, a simple backup and restore can only be used with deployments in which an embedded Platform Services Controller is used and Enhanced Linked mode is not used. This is because replication may not properly recover from stale data in the VM Directory Services database.
As of vSphere 6.0 U1 VMware data protection can be used to back-up and restore all Platform Services Controller systems.
To see the options to backup an externally configured Platform Services Controller including configurations which are utilizing Enhanced Linked Mode, See VMware KB How to backup and restore vCenter Server 6.0 external deployment models (2110294) (http://kb.vmware.com/kb/2110294).
To see the options to backup an externally configured Platform Services Controller including configurations which are utilizing Enhanced Linked Mode, See VMware KB How to backup and restore vCenter Server 6.0 external deployment models (2110294) (http://kb.vmware.com/kb/2110294).
In addition, see VMware KB List of Recommended topologies for vSphere 6.0 (2108548) (http://kb.vmware.com/kb/2108548/) for further details on the recommended topologies.
Deployment Recommendations
The deployment can be a complex task depending on the size of the environment.
Note: VMware recommends virtualizing all of the vCenter components because it allows for all the benefits of using vSphere features such as VMware HA. The following recommendations are provided for virtualized systems. Physical systems will need to be protected appropriately.
I recommend the following configurations in my experiences:
- For sites that will not use enhanced linked mode, use an embedded Platform Services Controller.
- This will allow for simplicity in the environment including a single pane of glass view of all servers while reducing the administrative overhead of configuring the environment for availability.
- High-Availability is provided by VMware HA. Failure domain is limited to a single vCenter Server, as there is no dependency on external component connectivity for Platform Services Controller connectivity.
- For sites that will use Enhanced Linked use external Platform Service Controllers:
- This configuration will consist of using external Platform Services controllers and load balancers (recommended for High Availability where it is required). The number of controllers depends on the size of the environment:
- If between 2 and 4 VMware Solutions – a single Platform Services Controller will be required for no HA, and 2 will be required for HA configured behind a single load balancer.
- If between 4 and 8 VMware Solutions – two Platform Services Controllers linked together will be required for no HA, and four will be required for HA configured behind two load balancers (two behind each load balancer).
- If between 8 and 10 VMware Solutions – three Platform Services Controllers linked together will be required for no HA, and six will be required for HA configured behind three load balancers (two behind each load balancer).
- High availability is provided by having multiple Platform Services Controllers and a load balancer to provide failure protection. In addition to this, all components are still protected by VMware HA. This will limit the failure implications of having a single Platform Services Controller, assuming that they are running on different ESXi hosts.
I close off this page by saying that simplicity is key. The configuration of High Availability for the PSC often times adds more complexity than is required. If VMware HA is good enough to meet the needs of the RTO and RPO, then don't worry about configuring a load balancer. In most cases if one is down, than the other will also be down and therefore the benefit of using a load balancer is negated and just adds complexity. I personally think that for the majority of cases that I have seen that pure VMware HA is good enough for the majority of configurations.
No comments:
Post a Comment