Dell Technologies has simplified the process of bootstrapping the OpenShift Container Platform 4.6 cluster. To use the simplified process, ensure that:

• The cluster is provisioned with network switches and servers.
• Network cabling is complete.
• Internet connectivity has been provided to the cluster. Internet connectivity is necessary to install OpenShift Container Platform 4.6.

The deployment procedure begins with initial switch provisioning. This step enables preparation and installation of the CSAH node, involving:

• Installing Red Hat Enterprise Linux 7
• Subscribing to the necessary repositories
• Creating an Ansible user account
• Cloning a GitHub Ansible playbook repository from the Dell ESG container repository
• Running an Ansible playbook to initiate the installation process

Dell Technologies has generated Ansible playbooks that fully prepare the CSAH node. Before the installation of the OpenShift Container Platform 4.6 cluster begins, the Ansible playbook sets up a PXE server, DHCP server, DNS server, HAProxy, and HTTP server. The playbook also creates ignition files to drive installation of the bootstrap, control plane, and compute nodes. It also starts the bootstrap VM to initialize control plane components. The playbook presents a list of node types that must be deployed in top-down order.

Note: For enterprise sites, consider deploying appropriately hardened DHCP and DNS servers. Similarly, consider using resilient multiple-node HAProxy configuration. The Ansible playbook for this design deploys a single HAProxy instance. This guide provides CSAH Ansible playbooks for reference only at the implementation stage.

The Ansible playbook creates an install-config.yaml file that is used to control deployment of the bootstrap node. For more information, see the Dell EMC Ready Stack: Red Hat OpenShift Container Platform 4.6 Deployment Guide at the Dell Technologies Solutions Info Hub for Containers. An ignition configuration control file starts the bootstrap node, as shown in the following figure:

Figure 4.                  Installation workflow: Creating the bootstrap, control-plane, and compute nodes

Note: An installation that is driven by ignition configuration generates security certificates that expire after 24 hours. You must install the cluster before the certificates expire, and the cluster must operate in a viable (nondegraded) state so that the first certificate rotation can be completed.

The cluster bootstrapping process consists of the following phases:

1. After startup, the bootstrap VM creates the resources that are required to start the control-plane nodes. Do not interrupt this process.

2. The control-plane nodes pull resource information from the bootstrap VM to bring them up into a viable state. This resource information is used to form the etcd control plane cluster.
3. The bootstrap VM instantiates a temporary Kubernetes control plane that is under etcd control.
4. A temporary control plane loads the application workload control plane to the control-plane nodes.
5. The temporary control plane is shut down, handing control over to the now viable control-plane nodes.
6. OpenShift Container Platform components are pulled into the control of the control-plane nodes.
7. The bootstrap VM is shut down.

The control-plane nodes now drive creation and instantiation of the compute nodes.

8. The control plane adds operator-based services to complete the deployment of the OpenShift Container Platform ecosystem.

The cluster is now viable and can be placed into service in readiness for Day-2 operations. You can expand the cluster by adding compute nodes.