Disclaimer : This post has been originally published on SVA’s Focus IT blogs in german language and translated my me using google translator.
To access original blog Click Here
As a Red Hat Premium Partner and Nutanix Reseller Champion Partner, SVA welcomes the partnership of our focus partners that was concluded on July 29, 2021. The created this press release, we took an opportunity , us with the automated installation of Open Shift to Nutanix to deal.
Fig. 1: Redhat Openshift on Nutanix AHV
Source: Nutanix Blog
Many SVA customers 1 already rely on the hyper-convergent Nutanix Webscale architecture in their data centers, often with the cost-neutral Nutanix Acropolis Hypervisor AHV. As the largest Nutanix Reseller Champion Partner in EMEA, SVA looks after all customer groups equally: From small to medium-sized customers or, of course, enterprise customers with more than 500 nodes – we have everything in our program!
Especially with enterprise customers, sooner or later you come across large RedHat installations, this customer group attaches particular importance to a stable and supported Linux distribution → always with enterprise support.
When containers come into play, many of our customers rely on the RedHat Openshift Container Platform (OCP), in fact the enterprise standard in this segment.
It has been particularly painful over the last few years that RedHat does not support the Nutanix Acropolis Hypervisor AHV as an officially certified hypervisor, although Acropolis, like RedHat Virtualization (RHV), also relies on KVM (Kernel Virtual Machine) as a substructure. From a technical point of view there was no real problem, RedHat Enterprise Linux RHEL and the RedHat Openshift container platform OCP ran without problems but were not officially supported by RedHat.
Both players have now heard their customers – with the partnership between Nutanix and RedHat announced on July 29, 2021, there are no longer any support restrictions \ o /
Our experts took this as an opportunity to take a closer look at the setup options of Openshift on Nutanix Acropolis Hypervisor AHV. It quickly became apparent that the “manual” installation did not meet the expectations of our customers, the specifications include an automated and repeatable setup without additional 3rd party tools → This is exactly where the SVA comes into play with its years of expertise in the enterprise environment
Get the overview
If you want to get started quickly with OpenShift, you usually fall back on the IPI (installer-provisioned infrastructure) installation variant . The point is quickly reached at which adjustments such as changing host names on the cluster are required or desired.
Another important point when choosing the installation variant is the existing infrastructure. Factors such as DHCP, DNS and access to the Internet play an important role in the selection of the installation variant and the installation media used for it. We often advise our customers in the on-prem environment to use the UPI (user-provisioned infrastructure) installation variant right from the start and to adapt this accordingly to the conditions in the data center.
It is advisable to set the installation to the UPI (user-provisioned infrastructure) installation variant right from the start.
Before the installation can start, preparatory work is required. With all OpenShift installation variants, regardless of the platform, the DNS entries must be set in advance.
We use a Linux system, the so-called Helpernode, to install OpenShift. The new CoreOS ISO file will be created on this system. This in turn is used to create the virtual machines on the Nutanix AHV. To provide the so-called ignition files, an NGINX web server was started in a container on the helpernode. A load balancer, also in the form of a container, was provided on the system for our laboratory setup. We have packed the requirements for a successful cluster installation, the provision of the VMs and the actual OpenShift installation into a single script that is executed on the Helpernode.
The Nutanix platform itself can be used and addressed in a variety of ways. In addition to the Restfull API, the Powershell module and the nCLI, it is also possible to work directly with the Acropolis CLI aCLI via SSH connection.
The second variant was chosen because our automation is completely scripted via bash. In addition, if possible, no (paid) 3rd party tools or proprietary tools should be used.
OpenShift installation history
Regardless of the selected installation variant (IPI or UPI), the installation process is identical. The values required for the installation are stored in the install-config.yaml file and used in the further course of the installation.
Fig. 2: RedHat Openshift Setup
Based on the created install-config.yaml file, the OpenShift installation process starts. The Bootstrap Node is required during the initial installation to install the OpenShift Control Plane. If the control plane is ready for use, the compute nodes are installed, which later process the actual workload. After a successful cluster installation, the bootstrap node is no longer required.
Fig. 3: Redhat Openshift Bootstrap Workflow
In order to automatically carry out the OpenShift installation in our laboratory, the following steps were automated:
- Install cluster tools
- Install Image Server
- Install Ignition Server
- Install LoadBalancer
- Build CoreOS ISO image
- Nutanix: Provide Customized CoreOS Image
- Create OCP SSH key
- Create install-config.yaml
- Generate manifestos
- Create Ignition Files
- Nutanix: Create OCP Nodes
- Nutanix: Install CSI Driver
Video 1: OpenShift @AHV – SVA
After the Nutanix-specific hurdles, such as changing the boot order, were mastered, the installation of OpenShift on AHV ran smoothly in the familiar manner. However, a small step backwards was made with the provision of the LoadBalancer. The high-availability HA proxy integrated in OpenShift had to be implemented by manual installation, as is known from OpenShift <4.5.
Due to the lack of Nutanix integration in OpenShift, it is not yet possible to automatically scale additional compute nodes. As announced by Nutanix, the integration is already being worked on. We are looking forward to the upcoming releases and will continue to follow the OpenShift topic on Nutanix AHV with excitement.
Until then, we as SVA already have a solution at the start for our customers which we can fully support, we use the mechanisms provided in the products and do not have to make any changes to the OpenShift or Nutanix AHV products. This guarantees 100% manufacturer support and we are always upgradeable.
1 In this article, “customer” does not mean private persons, but legal persons or companies.