The installation of OpenShift Container Platform on Amazon Web Services (AWS) involves a series of structured steps that ensure the successful deployment and configuration of a Kubernetes-based container orchestration platform. This guide provides an in-depth exploration of the prerequisites, procedures, and best practices associated with this process, drawing exclusively from the provided source material. The focus is on the technical aspects, including directory setup, configuration file generation, and the use of SSH keys for secure access.
Introduction
OpenShift Container Platform (OCP) is a powerful tool for deploying and managing containerized applications. When deploying OCP on AWS, users must follow a series of well-defined steps to ensure a smooth and secure installation. The process begins with the preparation of the AWS environment, followed by the extraction of the OCP installation program and the creation of an installation directory. The next phase involves generating the installation configuration file and making necessary modifications to suit specific deployment requirements. Finally, the installation process is initiated, and post-installation steps are taken to ensure the cluster operates as intended.
The following sections will detail each step of the installation process, emphasizing the importance of each phase and the potential pitfalls to avoid. By the end of this guide, users will have a comprehensive understanding of how to deploy OCP on AWS, leveraging the tools and configurations provided in the source material.
Prerequisites for OpenShift Container Platform Installation on AWS
Before beginning the installation of OpenShift Container Platform on AWS, several prerequisites must be met. These include setting up an AWS account and configuring the necessary permissions, ensuring access to the OCP installation program, and obtaining the required pull secret for the cluster.
Configuring the AWS Account
The first step in the installation process is to configure an AWS account. This involves creating an AWS profile or ensuring that the AWS access key ID and secret access key are available for the user who will run the installation program. These credentials are essential for authenticating with AWS services during the installation process.
Obtaining the OpenShift Installation Program and Pull Secret
The OpenShift installation program is a critical component of the deployment process. Users must download the appropriate version of the installation program for their host operating system and architecture. Once downloaded, the installation program must be extracted using a command such as tar -xvf openshift-install-linux.tar.gz.
In addition to the installation program, users must obtain the pull secret from the Red Hat OpenShift Cluster Manager. The pull secret is necessary for authenticating with the services that provide container images for OCP components, including Quay.io. This secret ensures that the installation process can access the required container images without interruption.
Setting Up the Installation Directory
The installation process requires the creation of an empty directory to store the files generated during the installation. It is crucial to ensure that this directory is empty, as some installation assets, such as bootstrap X.509 certificates, have short expiration intervals. Reusing an installation directory from a previous deployment is not recommended, as the file names for installation assets may change between releases. If users wish to reuse individual files from another cluster installation, they should exercise caution when copying them into the directory.
Generating the Installation Configuration File
Once the prerequisites are in place, the next step is to generate the installation configuration file. This file, named install-config.yaml, contains the necessary parameters for the OCP cluster deployment. The configuration file can be created by running the command ./openshift-install create install-config --dir <installation_directory>. Users are prompted to provide values for various parameters, including the base domain, cluster name, and AWS region.
Selecting the Platform and AWS Region
During the configuration process, users are prompted to select AWS as the platform for the cluster deployment. If an AWS profile is not already stored on the user's computer, they will need to enter the AWS access key ID and secret access key for the configured user. Additionally, users must select the AWS region where the cluster will be deployed. This selection is critical, as it determines the physical location of the cluster and can impact performance and compliance requirements.
Specifying the Base Domain
The base domain is another essential parameter in the configuration file. It is used to create routes to the OCP cluster components, and the full DNS name for the cluster is a combination of the base domain and the cluster name. Users should ensure that the base domain is correctly configured, as it is a fundamental part of the cluster's network infrastructure.
Providing an SSH Key
An optional but recommended step during the configuration process is to provide an SSH public key. This key is used to authenticate SSH access to the RHCOS nodes, enabling password-less authentication for the core user. If users anticipate the need for installation debugging or disaster recovery, they should ensure that the SSH key is in place. The key is added to the ~/.ssh/authorized_keys list on each node, allowing users to access the nodes via SSH using the key pair.
Customizing the Installation Configuration
After generating the install-config.yaml file, users may choose to customize the installation configuration based on their specific requirements. This includes modifying parameters such as the IP address blocks for the cluster network, which can be expanded if necessary. It is important to note that only IPv4 addresses are supported in the current configuration.
Modifying the Installation Configuration File
Users can modify the install-config.yaml file to provide more details about the platform. However, once the installation process begins, these parameters cannot be modified. Therefore, it is crucial to review and finalize all configuration settings before proceeding with the installation.
Creating an Ingress Controller
One of the customization options available is the creation of an Ingress Controller backed by an AWS NLB. This can be achieved by creating a file named cluster-ingress-default-ingresscontroller.yaml in the manifests/ directory. The file should contain a custom resource (CR) that describes the Operator configuration. After creating the file, users should ensure that it is correctly configured to meet their networking requirements.
Initiating the Installation Process
With the installation directory set up and the configuration file generated, the next step is to initiate the installation process. This is done by running the command ./openshift-install create cluster --dir <installation_directory> --log-level=info. The --log-level=info flag ensures that detailed logs are generated, which can be useful for troubleshooting if the installation encounters any issues.
Monitoring the Installation
During the installation process, users should monitor the progress and ensure that the cluster is being deployed correctly. The installation program will create several files in the specified directory, which are essential for the successful deployment of the cluster. It is important to note that deleting these files will not remove the cluster, even if the installation fails. To remove the cluster, users must complete the OpenShift Container Platform uninstallation procedures specific to their cloud provider.
Post-Installation Steps
After the installation process is complete, several post-installation steps should be taken to ensure that the cluster operates as intended. These steps include verifying the cluster's health, checking the status of the nodes, and ensuring that all services are running correctly.
Verifying the Cluster Health
To verify the health of the cluster, users can use the kubectl command to check the status of the nodes and the services running within the cluster. This step is critical, as it helps identify any issues that may have arisen during the installation process. If any issues are detected, users should refer to the logs generated during the installation to troubleshoot and resolve them.
Accessing the Cluster
Once the cluster is up and running, users should ensure that they can access it using the SSH key provided during the installation process. This allows them to perform any necessary maintenance tasks or troubleshooting if required. Additionally, users should verify that the cluster is accessible via the base domain and that all services are correctly configured.
Conclusion
The installation of OpenShift Container Platform on AWS is a complex but manageable process that requires careful planning and execution. By following the steps outlined in this guide, users can ensure a successful deployment of their OCP cluster. The key to a smooth installation lies in understanding the prerequisites, generating the correct configuration files, and monitoring the installation process to address any issues that may arise. With the right approach and attention to detail, users can deploy a robust and scalable OCP environment on AWS, leveraging the full potential of container orchestration for their applications.