The difference between VMware vSphere LCM (vLCM) and Dell EMC VxRail LCM is still a trending topic that most HCI customers and prospects want more information about. While we compared the two methods at a high level in our previous blog post, let’s dive into the more technical aspects of the LCM operations of VMware vLCM and VxRail LCM. The detailed explanation in this blog post should give you a more complete understanding of your role as an administrator for cluster lifecycle management with vLCM versus VxRail LCM.

Even though vLCM has introduced a vast improvement in automating cluster updates, lifecycle management is more than executing cluster updates. With vLCM, lifecycle management is still very much a customer-driven endeavor. By contrast, VxRail’s overarching goal for LCM is operational simplicity, by leveraging Continuously Validated States to drive cluster LCM for the customer. This is a large part of why VxRail has over 8,600 customers since it was launched in early 2016.

In this blog post, I’ll explain the four major areas of LCM:

• Defining the initial baseline configuration
• Planning for a cluster update
• Executing the cluster update
• Sustaining cluster integrity over the long term

Defining the initial baseline configuration

The baseline configuration is a vital part of establishing a steady state for the life of your cluster. The baseline configuration is the current known good state of your HCI stack. In this configuration, all the component software and firmware versions are compatible with one another. Interoperability testing has validated full stack integrity for application performance and availability while also meeting security standards in place. This is the ‘happy’ state for you and your cluster. Any changes to the configuration use this baseline to know what needs to be rectified to return to the ‘happy’ state.

How is it done with vLCM?

vLCM depends on the hardware vendor to provide a Hardware Management Services virtual machine. Dell provides this support for its Dell EMC PowerEdge servers, including vSAN ReadyNodes. I’ll use this implementation to explain the overall process. Dell EMC vSAN ReadyNodes use the OpenManage Integration for VMware vCenter (OMIVV) plugin to connect to and register with the vCenter Server.

Once the VM is deployed and registered, you need to create a credential-based profile. This profile captures two accounts: one for the out-of-band hardware interface, the iDRAC, and the other for the root credentials for the ESXi host. Future changes to the passwords require updating the profile accordingly.

With the VM connection and profile in place, a Catalog XML file is used by vLCM to define the initial baseline configuration. To create the Catalog XML file, you need to install and configure the Dell Repository Manager (DRM) to build the hardware profile. Once a profile is defined to your specification, it must then be exported and stored on an NFS or CIFS share. The profile is then used to populate the Repository Profile data in the OMIVVV UI. If you are unsure of your configuration, refer to the vSAN Hardware Compatibility List (HCL) for the specific supported firmware versions. Once the hardware profile is created, you can then associate it with the cluster profile. With the cluster profile defined, you can enable drift detection. Any future change to the Catalog XML file is done within the DRM.

It’s important to note that vLCM was introduced in vSphere 7.0. To use vLCM, you must first update or deploy your clusters to run vSphere 7.x.

How is it done with VxRail LCM?

With VxRail, when the cluster arrives at the customer data center, it’s already running in a ‘happy’ state. For VxRail, the ‘happy’ state is called Continuously Validated States. The term is pluralized because VxRail defines all the ‘happy’ states that your cluster will update to over time. This means that your cluster is always running in a ‘happy’ state without you needing to research, define, and test to arrive at Continuously Validated States throughout the life of your cluster. VxRail – well, specifically the VxRail engineering team - does it for you. This has been a central tenet of VxRail since the product first launched with vSphere 6.0. Since then it has helped customers transition to vSphere 6.5, 6.7, and now 7.0.

Once the VxRail cluster initialization is completed, use your Dell EMC Support credentials to configure the VxRail repository setting within vCenter. VxRail Manager plugin to vCenter will automatically connect to the VxRail repository at Dell EMC and pull down the next available update package.

Figure 1  Defining the initial baseline configuration

Planning for a cluster update

Updates are a constant in IT, and VMware is constantly adding new capabilities or product/security fixes that require updating to newer versions of software. Take for example the vSphere 7.0 Update 1 release that VMware and Dell Technologies just announced. Those eye-opening features are available to you when you update to that release. You can check out just how often VMware has historically updated vSphere here: https://kb.vmware.com/s/article/2143832.

As you know, planning for a cluster update is an iterative process with inherent risk associated with it. Failing to plan diligently can cause adverse effects on your cluster, ranging from network outages and node failure to data unavailability or data loss. That said, it’s important to mitigate the risk where you can.

How is it done with vLCM?

With vLCM, the responsibility of planning for a cluster update rests on the customers’ shoulders, including the risk. Understanding the Bill of Materials that makes up your server’s hardware profile is paramount to success. Once all the components are known, and a target version of vSphere ESXi is specified, the supported driver and firmware version needs to be investigated and documented. You must consult the VMware Compatibility Guide to find out which drivers/firmware are supported for each ESXi release.

It is important to note that although vLCM gives you the toolset to apply firmware and driver updates, it does not validate compatibility or support for each combination for you, except for the HBA Driver. This task is firmly in the customer’s domain. It is advisable to validate and test the combination in a separate test environment to ensure that no performance regression or issues are introduced into the production environment. Interoperability testing can be an extensive and expensive undertaking. Customers should create and define robust testing processes to ensure that full interoperability and compatibility is met for all components managed and upgraded by vLCM.

With Dell EMC vSAN Ready Nodes, customers can rest assured that the HCL certification and compatibility validation steps have been performed. However, the customer is still responsible for interoperability testing.

How is it done with VxRail LCM?

VxRail engineering has taken a unique approach to LCM. Rather than leaving the time-consuming LCM planning to already overburdened IT departments, they have drastically reduced the risk by investing over $60 million, more than 25,000 hours of testing for major releases, and more than 100 team members into a comprehensive regression test plan. This plan is completed prior to every VxRail code release. (This is in addition to the testing and validation performed by PowerEdge, on which VxRail nodes are built.)

Dell EMC VxRail engineering performs this testing within 30 days of any new VMware release (even quicker for express patches), so that customers can continually benefit from the latest VMware software innovations and confidently address security vulnerabilities. You may have heard this called “synchronous release”.

The outcome of this effort is a single update bundle that is used to update the entire HCI stack, including the operating system, the hardware’s drivers and firmware, and management components such as VxRail Manager and vCenter. This allows VxRail to define the declarative configuration we mentioned previously (“Continuously Validated States”), allowing us to move easily from one validated state to the next with each update.

Figure 2  Planning for a cluster update

Executing the cluster update

The biggest improvement with vLCM is its ability to orchestrate and automate a full stack HCI cluster update. This simplifies the update operation and brings enormous time savings. This process is showcased in a recent study performed by Principled Technologies with PowerEdge Servers with vSphere (not including vSAN).

How is it done with vLCM?

The first step is to import the ESXi ISO via the vLCM tab in the vCenter Server UI. Once uploaded, select the relevant cluster, ensure that the cluster profile (created in the initial baseline configuration phase) is associated with the cluster being updated. Now, you can apply the target configuration by editing the ESXi image and, from the OMIVV UI, choose the correct firmware and driver to apply to the hardware profile. Once a compliance scan is complete, you will have the option to remediate all hosts.

If there are multiple homogenous clusters you need to update, it can be as easy as using the same cluster profile to execute the cluster update against. However, if the next cluster has a different hardware configuration, then you would have to perform the above steps over again. Customers with varying hardware and software requirements for their clusters will have to repeat many of these steps, including the planning tasks, to ensure stack integrity.

How it is done with VxRail LCM?

With VxRail and Continuously Validated States, updating from one configuration to another is even simpler. You can access the VxRail Manager directly within the vCenter Server UI to initiate the update. The LCM operation automatically retrieves the update bundle from the VxRail repository, runs a full stack pre-update health check, and performs the cluster update.

With VxRail, performing multi-cluster updates is as simple as performing a single-cluster update. The same LCM cluster update workflow is followed. While different hardware configurations on separate clusters will add more labor for IT staff for vSAN Ready Nodes, this doesn’t apply to VxRail.  In fact, in the latest release of our SaaS multi-cluster management capability set, customers can now easily perform cluster updates at scale from our cloud-based management platform, MyVxRail.

Figure 3  Executing a cluster update

Sustaining cluster integrity over the long term

The long-term integrity of a cluster outlasts the software and hardware in it. As mentioned earlier, because new releases are made available frequently, software has a very short life span. While hardware has more staying power, it won’t outlast some of the applications running on them. New hardware platforms will emerge. New hardware devices will enter the market that will launch new workloads, such as machine learning, graphics rendering, and visualization workflows. You will need the cluster to evolve non-disruptively to deliver the application performance, availability, and diversity your end-users require.

How is it done with vLCM?

In its current form, vLCM will struggle in long-term cluster lifecycle management. In particular, its inability to support heterogeneous nodes (nodes with different hardware configurations) in the same cluster will limit its application diversification and its ability to take advantage of new hardware platforms without impacting end-users.

How it is done with VxRail LCM?

VxRail LCM touts its ability to allow customers to grow non-disruptively and to scale their clusters over time. That includes adding non-identical nodes into the clusters for new applications, adding new hardware devices for new applications or more capacity, or retiring old hardware from the cluster.

Conclusion 

Figure 4  Comparing vSphere LCM and VxRail LCM cluster update operations driven by the customer

The VMware vLCM approach empowers customers who are looking for more configuration flexibility and control. They have the option to select their own hardware components and firmware to build the cluster profile. With this freedom comes the responsibility to define the HCI stack and make investments in equipment and personnel to ensure stack integrity. vLCM supports this customer-driven approach with improvements in cluster update execution for faster outcomes.

Dell EMC VxRail LCM continues to take a more comprehensive approach to optimize operational efficiency from the point of the view of the customer. VxRail customers value its LCM capabilities because it reduces operational time and effort which can be diverted into other areas of need in IT. VxRail takes on the responsibility to drive stack integrity for the lifecycle management of the cluster with Continuously Validated States. And VxRail sustains stack integrity throughout the life of the cluster, allowing you to simply and predictably evolve with technology trends.

Cliff Cahill
VxRail Engineering Technologist
Twitter @cliffcahill
LinkedIn http://linkedin.com/in/cliffcahill

Many customers are looking at Infrastructure as Code (IaC) as a better way to automate their IT environment, which is especially relevant for those adopting DevOps. However, not many customers are aware of the capability of accelerating IaC implementation with VxRail, which we have offered for some time already—Ansible Modules for Dell VxRail.

What is it? It's the Ansible collection of modules, developed and maintained by Dell, that uses the VxRail API to automate VxRail operations from Ansible.

By the way, if you're new to the VxRail API, first watch the introductory whiteboard video available on YouTube.

Ansible Modules for Dell VxRail are well-suited for IaC use cases. They are written in such a way that all requests are idempotent and hence fault-tolerant. This means that the result of a successfully performed request is independent of the number of times it is run.

Besides that, instead of just providing a wrapper for individual API functions, we automated holistic workflows (for instance, cluster deployment, cluster expansion, LCM upgrade, and so on), so customers don't have to figure out how to monitor the operation of the asynchronous VxRail API functions.  These modules provide rich functionality and are maintained by Dell; this means we're introducing new functionality over time. They are already mature—we recently released version 1.4.

Finally, we are also reducing the risk for customers willing to adopt the Ansible modules in their environment, thanks to the community support model, which allows you to interact with the global community of experts. From the implementation point of view, the architecture and end-user experience are similar to the modules we provide for Dell storage systems.

Getting Started

Ansible Modules for Dell VxRail are available publicly from the standard code repositories: Ansible Galaxy and GitHub. You don't need a Dell Support account to download and start using them.

Requirements

The requirements for the specific version are documented in the "Prerequisites" section of the description/README file.

In general, you need a Linux-based server with the supported Ansible and Python versions. Before installing the modules, you have to install a corresponding, lightweight Python SDK library named "VxRail Ansible Utility," which is responsible for the low-level communication with the VxRail API. You must also meet the minimum version requirements for the VxRail HCI System Software on the VxRail cluster.

This is a summary of requirements for the latest available version (1.4.0) at the time of writing this blog:

Installation

You can install the SDK library by using git and pip commands. For example:

git clone https://github.com/dell/ansible-vxrail-utility.git

cd ansible-vxrail-utility/
pip install .

Then you can install the collection of modules with this command:

ansible-galaxy collection install dellemc.vxrail:1.4.0

Testing

After the successful installation, we're ready to test the modules and communication between the Ansible automation server and VxRail API.

I recommend performing that check with a simple module (and corresponding API function) such as dellemc_vxrail_getsysteminfo, using GET /system to retrieve VxRail System Information.

Let's have a look at this example (you can find the source code on GitHub):

 
Note that this playbook is run on a local Ansible server (localhost), which communicates with the VxRail API running on the VxRail Manager appliance using the SDK library. In the vars section, , we need to provide, at a minimum, the authentication to VxRail Manager for calling the corresponding API function. We could move these variable definitions to a separate file and include the file in the playbook with vars_files. We could also store sensitive information, such as passwords, in an encrypted file using the Ansible vault feature. However, for the simplicity of this example, we are not using this option.

After running this playbook, we should see output similar to the following example (in this case, this is the output from the older version of the module):

Cluster expansion example

Now let's have a look at a bit more sophisticated, yet still easy-to-understand, example. A typical operation that many VxRail customers face at some point is cluster expansion. Let's see how to perform this operation with Ansible (the source code is available on GitHub):

In this case, I've exported the definitions of the sensitive variables, such as vcpasswd, mgt_passwd, and root_passwd, into a separate, encrypted Ansible vault file, sensitive-vars.yml, to follow the best practice of not storing them in the clear text directly in playbooks.

As you can expect, besides the authentication, we need now to provide more parameters—configuration of the newly added host—defined in the vars section. We select the new host from the pool of available hosts, using the PSNT identifier (host_psnt variable).

This is an example of an operation performed by an asynchronous API function. Cluster expansion is not something that is completed immediately but takes minutes. Therefore, the progress of the expansion is monitored in a loop until it finishes or the number of retries is passed. If you communicated with the VxRail API directly by using the URI module from your playbook, you would have to take care of such monitoring logic on your own; here, you can use the example we provide.

You can watch the operation of the cluster expansion Ansible playbook with my commentary in this demo: 

Getting help

The primary source of information about the Ansible Modules for Dell VxRail is the documentation available on GitHub. There you'll find all the necessary details on all currently available modules, a quick description, supported endpoints (VxRail API functions used), required and optional parameters, return values, and location of the log file (modules have built-in logging feature to simplify troubleshooting— logs are written in the /tmp directory on the Ansible automation server). The GitHub documentation also contains multiple samples showing how to use the modules, which you can easily clone and adjust as needed to the specifics of your VxRail environment.

There's also built-in documentation for the modules, accessible with the ansible-doc command.

Finally, the Dell Automation Community is a public discussion forum where you can post your questions and ask for help as needed.

Conclusion 

I hope you now understand the Ansible Modules for Dell VxRail and how to get started. Let me quickly recap the value proposition for our customers. The modules are well-suited for IaC use cases, thanks to automating holistic workflows and idempotency. They are maintained by Dell and supported by the Dell Automation Community, which reduces risk. These modules are much easier to use than the alternative of accessing the VxRail API on your own. We provide many examples that can be adjusted to the specifics of the customer’s environment.

Resources

To learn more, see these resources:

• On-demand recording of the recent Tech Exchange Live session: "Infrastructure as Code with VxRail," where I dive a bit deeper into the Ansible Modules for VxRail, and my colleague Steffen from VMware discusses the basics of Terraform integration with VxRail.
• Ansible Modules for Dell VxRail on GitHub, which is the central code repository for the modules. It also contains complete product documentation and examples.
• Try the new VxRail API Hands-on-Lab available in the Dell Technologies Demo Center, which we introduced at Dell Technologies World earlier this year. Module 3: Cluster Expansion or Scaling Out allows you to get hands-on experience with the modules without the need to have access to a VxRail system. Your Dell account team can help you access the lab.

The following links provide additional information:

• YouTube video: Ansible Modules for Dell VxRail
• Dell Automation Community
• YouTube video: Level up your HCI automation with VxRail API
• Blog: VxRail API—Updated List of Useful Public Resources
  
  

Author: Karol Boguniewicz, Senior Principal Engineering Technologist, VxRail Technical Marketing
Twitter: @cl0udguide