Cluster QuickStart Tech Note
A solid foundation is essential to any type of structure or platform. An HCI cluster is no exception. It is important to have a consistent build across all nodes in a cluster. This includes hardware, software versions, network configuration, cluster settings, and so on. Many administrators build their clusters manually. This approach is fine, but it does introduce more opportunity for errors and it can take a significant amount of time depending on the size of the cluster. Another option is automation through scripting. While this does reduce errors and the amount of time needed, it does require the skill set and time to build and test and automation script. This dilemma uncovered the need for a solution that provides some automation and consistency without the need for building and maintaining scripts. vSphere 6.7 U1 and vSAN 6.7 U1 introduced Cluster QuickStart. This is a new feature in the vSphere Client to ease the configuration of a new cluster. It also simplifies the process of adding new hosts to an existing cluster.
Scripting the configuration of an HCI cluster provides automation and consistency but requires someone to build and maintain these scripts as new hardware is introduced, new software is released, and requirements change. Many organizations lack individuals with the skill set to write scripts. There is also risk that the person who does this scripting leaves the organization, which might hinder this method of automation until a new individual with suitable skills is found.
The other option is building each cluster manually. Each host must have ESXi installed and then it is added to the cluster. Some configuration items can be streamlined through the use of Host Profiles and Virtual Distributed Switches. However, these features do not cover all settings and they offer little guidance or recommendations for optimal configurations. Building clusters manually also takes more time. This additional time can be considerable in larger organizations with many hosts and clusters.
vSphere 6.7 U1 and vSAN 6.7 U1 introduced Cluster QuickStart. This enhancement provides a streamlined method for building and expanding an HCI cluster. It simplifies the configuration of the cluster and helps ensure consistency across all of the hosts in the cluster. It also performs checks and makes recommendations according to VMware best practices to help ensure the highest levels of stability and performance. Cluster QuickStart can be navigated in the vSphere Client UI and automated using vSphere APIs.
It has always been recommended that all hosts in a cluster have the same or a very similar hardware configuration. Assuming that recommendation is followed, Cluster QuickStart makes it quick and easy to stand up a new HCI cluster. There are three main steps in Cluster QuickStart: Cluster Basics, Add Hosts, and Configure Cluster.
Figure 1. Cluster QuickStart – Three Main Steps
Cluster Basics provides options to enable vSphere Distributed Resource Scheduler (DRS), vSphere High Availability (HA), and vSAN. You can also change the name of the cluster. Note that the options are enabled with the default settings, but these settings can be changed later in the Cluster QuickStart workflow.
Figure 2. Cluster Basics – Edit Cluster Settings
Hosts are added to the cluster after the cluster settings have been configured. Hosts already managed by vCenter Server appear in the Existing Hosts section.
Figure 3. Add existing hosts to a cluster
New hosts can be added by entering the IP address or FQDN for each host that is to be added along with the username and password. A checkbox provides the option to use the same username and password for all new hosts.
Figure 4. Add new hosts to a cluster
Hosts are placed in maintenance mode and added to the cluster. Services that were enabled in the first step are configured with the default settings across the hosts. Multiple configuration items are checked as shown in the figure below. This initial check verifies requirements and recommendations such as time synchronization, software version compatibility, and configuration consistency. It also verifies the hardware in use is supported and certified for use with vSphere and vSAN. In the example below, we see that at least one of the SCSI controllers in the cluster is not certified for use with vSAN. The controller(s) should be replaced. The “Re-validate” button would be used to verify all of the items in the list have passed this initial configuration check. It is also possible to add more hosts and rerun the validation step from here.
Figure 5. Configuration verification
We can also see in the figure above that the six hosts have not been configured. That is the last main step in Cluster QuickStart. The Configure Cluster step makes it easier to configure network settings, modify cluster services, and set up the vSAN datastore.
The first step in the Configure Cluster wizard is creating a vSphere Distributed Switch (VDS). This is in accordance with the recommendations in VMware Validated Designs. Port groups for the vMotion network and vSAN network can also be configured in this step. Creating a consistent network configuration across an HCI cluster has never been easier.
Figure 6. vSphere Distributed Switch and port groups
Figure 7. Physical adapters for vSphere Distributed Switch
Cluster QuickStart automatically enables and configures VMware vSphere Network I/O Control. The figure below shows the various traffic types and the number of shares assigned to each. Virtual Machine Traffic and vSAN are set to "High" while the others are set to "Normal." Virtual machines and vSAN will be allocated more of the available bandwidth relative to the other traffic types when there is contention for network resources.
Figure 8. Network I/O Control
The next two steps in the Configure Cluster wizard cover IP address configuration for vMotion and vSAN traffic. IPv4 and IPv6 are supported. DHCP can be specified for automatic network configuration or static addresses can be used. An AutoFill option is available to increment the host portion of the IP address and automatically populate the IP address, subnet, and gateway fields. This is much faster than entering each of these items manually for every host and it helps ensure consistent network addressing.
Figure 9. vSAN traffic network configuration
Advanced options include custom settings for vSphere HA, vSphere DRS, and vSAN. Examples for vSAN include the ability to configure a stretched cluster, enable data-at-rest encryption, turn on deduplication and compression, and set up fault domains. NTP can be set for all hosts in the cluster and it is possible to configure Enhanced vMotion Compatibility (EVC).
Figure 10. vSAN options
If vSAN is enabled for the cluster, disks must be claimed for the vSAN datastore. This involves selecting storage devices for the vSAN cache and capacity tiers. The wizard will make recommendations for the drive selection, which helps streamline the configuration process. Changes to the recommended configuration are easy to do, if needed.
Figure 11. Claiming disks for vSAN
Cluster QuickStart automatically configures the cluster based on the settings specified in the Configure Cluster wizard. These tasks happen automatically to save time and help ensure consistent configuration all while following recommendations based on VMware Validated Designs. After cluster configuration is complete, additional configuration and health checks are completed to verify the cluster is ready for production use. If an issue is found, an administrator can troubleshoot and re-validate the configuration to verify the issue has been resolved.
Figure 12. Cluster configuration validated
Cluster QuickStart reduces the amount of time needed to configure a cluster. This includes setting up services such as vSphere HA and vSAN; verifying hardware and software compatibility; deploying Virtual Distributed Switches; configuring network settings for vMotion and vSAN; creating a vSAN stretched cluster or vSAN fault domains; and ensuring consistent NTP configuration across the cluster. After the cluster is configured, a health check is performed to verify the configuration is ready for use and follows VMware Validated Design recommendations. All of this is done through a streamlined UI with no need for scripting. Cluster QuickStart can also be used to add new hosts to an existing cluster with speed and consistency. Properly configured clusters provide the best experience in terms of stability, performance, and ease of management.