Kubernetes

OpenShift provides an Operators section in its web console UI for the installation and management of operators on the cluster. OperatorHub The OperatorHub is an interface for searching and installing operators. It has the following categories of operators: Red Hat Operators: Operators developed and supported by Red Hat. Example: Red Hat Quay Operator Certified Operators: Operators listed by Red Hat’s Independent Software Vendors (ISVs). Example: CockroachDB Operator Red Hat Marketplace Operators: Applications purchased from Red Hat Marketplace available as Operators....

Applications built to be deployed on Kubernetes could be packaged as Operators. Operators automate the process of installation, updates, and management of the application. These automations are defined by developers based on the application’s business logic. An Operator consists of: Custom Resources (CRs) required by the application Custom controller for managing these CRs Control Loop A control loop is an infinite loop for monitoring the state of a system. If the desired state of the system is different from its current state then the control loop makes changes to the system until it reaches its desired state....

A container image is a static file that contains the necessary resources (packages, configuration, other dependencies) required to provision a container. It consists of multiple layered-filesystems and a Manifest file, containing its metadata. Open Container Initiative (OCI) Specification Open Container Initiative was established by The Linux Foundation in 2015 to provide Runtime specification Image specification Distribution specification for container images. A container image created from OCI Image specification should have...

Container Engines like Podman and Docker provide GUI and CLI utilities for managing the state of containers. They also provide features such as container image management, metrics, logging, and debugging tools. The examples in this article use Podman but CLI commands are mostly interoperable with Docker. We can install Podman on your system by following the steps in Podman Installation Instructions. Podman also provides a graphical interface for managing containers, images, and other resources called Podman Desktop....

To isolate the processes running inside a container from its host system, container engine uses the following four features: Namespaces Control Groups Secure Computing Security-Enhanced Linux Namespaces Namespaces are created to limit the reach of a container to its host’s resources. It helps with security and well as limits resources available to the container. Linux command lsns could be used for listing details of namespaces. The namespaces essential for containers are User, Mount, Unix Timesharing System, Process ID, Network, and Inter-Process Communication....