Glossary

This section defines a glossary of common KubeOps terms.

SINA package

SINA package is the .sina file packaged by bundling package.yaml and other essential yaml files and artifacts. This package is ready to install on your Kubernetes Clusters.

KubeOps Hub

KubeOps Hub is a secure repository where published SINA packages can be stored and shared. You are welcome to contribute and use public hub also at the same time KubeOps provides you a way to access your own private hub.

Installation Address

It is the distinctive address automatically generated for each published package on KubeOps Hub. It is constructed using name of package creator, package name and package version.
You can use this address at the time of package installation on your Kubernetes Cluster.

It is indicated by the install column in KubeOps Hub.

Deployment name

When a package is installed, SINA creates a deployment name to track that installation. Alternatively, SINA also lets you specify the deployment name of your choice during the installation.
A single package may be installed many times into the same cluster and create multiple deployments.
It is indicated by Deployment column in the list of package deployments.

Tasks

As the name suggests, “Tasks” in package.yaml are one or more sets of instructions to be executed. These are defined by utilizing Plugins.

Plugins

SINA provides many functions which enable you to define tasks to be executed using your package. These are called Plugins. They are the crucial part of your package development.

LIMAROOT Variable

LIMAROOT is an envoirment variable for LIMA. It is the place where LIMA stores information about your clusters. The environment variable LIMAROOT is set by default to /var/lima. However LIMA also facilitates setting your own LIMAROOT by yourself.

KUBEOPSROOT Variable

The environment variable KUBEOPSROOT stores the location of the SINA plugins and the config.yaml. To use the variable, the config.yaml and the plugins have to be copied manually.

apiVersion

It shows the supported KubeOps tool API version. You do not need to change it unless otherwise specified.

Registry

As the name suggests, it is the location where docker images can be stored. You can either use the default KubeOps registry or specify your own local registry for AirGap environments. You need an internet connection to use the default registry provided by KubeOps.

Maintenance Package

KubeOps provides a package for the supported Kubernetes tools. These packages help you update the Kubernetes tools to the desired versions on your clusters along with the dependencies.

Cluster

In computing, a cluster refers to a group of interconnected computers or servers that work together as a single system.

These machines, or nodes, are typically networked and collaborate to execute tasks or provide services. Clusters are commonly used in various fields such as distributed computing, high-performance computing, and cloud computing to improve reliability, scalability, and performance. In the context of technologies like Kubernetes, a cluster consists of multiple nodes managed collectively to deploy, manage, and scale containerized applications.

Container

A container is a lightweight, standalone package that includes everything needed to run a piece of software, including the code, runtime, libraries, and dependencies.

Containers are isolated from each other and from the underlying infrastructure, providing consistency and portability across different environments. Kubernetes manages containers, orchestrating their deployment, scaling, and management across a cluster of nodes. Containers are often used to encapsulate microservices or individual components of an application, allowing for efficient resource utilization and simplified deployment processes.

Drain-node

A Drain Node is a feature in distributed systems, especially prevalent in Kubernetes, used for gracefully removing a node from a cluster.

It allows the system to evict all existing workload from the node and prevent new workload assignments before shutting it down, ensuring minimal disruption to operations.

Kube-proxy

Kube-Proxy, short for Kubernetes Proxy, is a network proxy that runs on each node in a Kubernetes cluster. Its primary responsibility is to manage network connectivity for Kubernetes services. Its main tasks include service proxying and load balancing.

Kubelet

Kubelet is a crucial component of Kubernetes responsible for managing individual nodes in a cluster. It ensures that containers are running in pods as expected, maintaining their health and performance.

Kubelet communicates with the Kubernetes API server to receive instructions about which pods should be scheduled and executed on its node. It also monitors the state of these pods, reporting any issues back to the API server. Kubelet plays a vital role in the orchestration and management of containerized workloads within a Kubernetes cluster.

Node

A Kubernetes node oversees and executes pods.

It serves as the operational unit (virtual or physical machine) for executing assigned tasks. Similar to how pods bring together multiple containers to collaborate, a node gathers complete pods to work in unison. In large-scale operations, the goal is to delegate tasks to nodes with available pods ready to handle them.

Pod

In Kubernetes, a pod groups containers and is the smallest unit managed by the system.

Each pod shares an IP address among its containers and resources like memory and storage. This allows treating the containers as a single application, similar to traditional setups where processes run together on one host. Often, a pod contains just one container for simple tasks, but for more complex operations requiring collaboration among multiple processes with shared data, multi-container pods simplify deployment.

For example, in an image-processing service creating JPEGs, one pod might have containers for resizing images and managing background tasks or data cleanup, all working together.

Registry

Helm registry serves as a centralized repository for Helm charts, facilitating the discovery, distribution, and installation of Kubernetes applications and services.

It allows users to easily find, share, and consume pre-packaged Kubernetes resources, streamlining the deployment process in Kubernetes environments.

Zone

A “zone” typically refers to a subset of the overall cluster that shares certain characteristics, such as geographic location or hardware specifications. Zoning helps distribute resources strategically and can enhance fault tolerance by ensuring redundancy within distinct zones.