Openshift Installation

 Installation Types

1. Full-Stack Automation
2. Pre-existing infrastructure 

Sequence to follow installing Openshift with Openshift installer 

1. Create install-config.yaml
2. Create Kubernetes manifests
3. Create ignition configuration files
4. Create the cluster

Kubernetes manifests and ignition configuration files are not exist already, these are created automatically in the create cluster step.

Deployment Process:

1. The bootstrap machine boots, and then starts hosting the remote resources required for booting the control plane machines. 
2. The control plane machines fetch the remote resources from the bootstrap machine and finish booting. 
3. The control plane machines form an Etcd cluster. 
4. The bootstrap machine starts a temporary Kubernetes control plane using the newly-created Etcd cluster. 
5. The temporary control plane schedules the control plane to the control plane machines. 
6. The temporary control plane shuts down and yields to the control plane. 
7. The bootstrap node injects components specific to OpenShift into the control plane. 
8. Finally, the installer tears down the bootstrap machine.

 Customizing an OpenShift Installation

The OpenShift installer allows very little customization of the initial cluster that it provisions. Most customization is performed after installation, including: 

• Defining custom storage classes for dynamic storage provisioning. 

• Changing the custom resources of cluster operators. 

• Adding new operators to a cluster. 

• Defining new machine sets.

 

To enable cluster management with OC command

export KUBECONFIG=${HOME}/ocp4-cluster/auth/kubeconfig

oc get clusterversion -o jsonpath='{}.items[].spec.clusterID}{"\n"}'

#Deleting an Openshift Cluster

openshift-install destroy cluster --dir=${HOME}/ocp4-cluster