--- title: "Containers & Kubernetes" lang: "en" author: "Mohammad Abu Mattar" canonical: https://mkabumattar.com/post/containers-and-kubernetes --- [Home](/)›[Glossary](/glossary)›[All Categories](/glossary/categories)›[Devops](/glossary/categories/devops) Glossary [Prev in DevopsCI/CD & Automation](/glossary/post/ci-cd-and-automation)[Next in DevopsDevOps Basics](/glossary/post/devops-basics) # Containers & Kubernetes Essential terms every DevOps engineer should know about containers and Kubernetes. 63 TermsPublished: 11 Apr 2026 [Devops](/glossary/categories/devops)[#containers](/glossary/tags/containers)[#docker](/glossary/tags/docker)[#kubernetes](/glossary/tags/kubernetes)[#orchestration](/glossary/tags/orchestration) [Markdown for AI(opens in a new tab)](/post/containers-and-kubernetes/index.md "Open the plain-Markdown version of this page, for pasting into an AI tool") [Facebook](https://facebook.com/sharer/sharer.php?u=https%3A%2F%2Fmkabumattar.com%2Fglossary%2Fpost%2Fcontainers-and-kubernetes "Share on Facebook")[Twitter](https://twitter.com/intent/tweet/?text=Containers%20%26%20Kubernetes&url=https%3A%2F%2Fmkabumattar.com%2Fglossary%2Fpost%2Fcontainers-and-kubernetes "Share on Twitter")[LinkedIn](https://www.linkedin.com/shareArticle?mini=true&url=https%3A%2F%2Fmkabumattar.com%2Fglossary%2Fpost%2Fcontainers-and-kubernetes&title=Containers%20%26%20Kubernetes&summary=Essential%20terms%20every%20DevOps%20engineer%20should%20know%20about%20containers%20and%20Kubernetes.&source=https://mkabumattar.com "Share on LinkedIn")[WhatsApp](https://wa.me/?text=Containers%20%26%20Kubernetes%20https%3A%2F%2Fmkabumattar.com%2Fglossary%2Fpost%2Fcontainers-and-kubernetes "Share on WhatsApp")[Telegram](https://t.me/share/url?url=https%3A%2F%2Fmkabumattar.com%2Fglossary%2Fpost%2Fcontainers-and-kubernetes&text=Containers%20%26%20Kubernetes "Share on Telegram")[Reddit](https://www.reddit.com/submit?url=https%3A%2F%2Fmkabumattar.com%2Fglossary%2Fpost%2Fcontainers-and-kubernetes&title=Containers%20%26%20Kubernetes "Share on Reddit")[Hacker News](http://news.ycombinator.com/submitlink?u=https%3A%2F%2Fmkabumattar.com%2Fglossary%2Fpost%2Fcontainers-and-kubernetes&t=Containers%20%26%20Kubernetes "Share on Hacker News")[Pinterest](https://pinterest.com/pin/create/button/?url=https%3A%2F%2Fmkabumattar.com%2Fglossary%2Fpost%2Fcontainers-and-kubernetes&media=&description=Essential%20terms%20every%20DevOps%20engineer%20should%20know%20about%20containers%20and%20Kubernetes. "Share on Pinterest")[Email]() This glossary covers essential terms for working with containers and Kubernetes: building Docker images, and managing workloads, networking, storage, scaling, and security in a Kubernetes cluster. Series [Containers & Kubernetes](/series/containers--kubernetes)1/2 [NextKubernetes Advanced](/glossary/post/kubernetes-advanced) All posts in this series (2) Glossary2 1. [Containers & KubernetesYou are here](/glossary/post/containers-and-kubernetes) 2. [Kubernetes Advanced](/glossary/post/kubernetes-advanced) ### Containers - [Container](#term-container) - [Docker](#term-docker) - [Dockerfile](#term-dockerfile) - [Docker Image](#term-docker-image) - [Docker Layer](#term-docker-layer) - [Docker Compose](#term-docker-compose) - [Container Registry](#term-container-registry) - [Docker Hub](#term-docker-hub) - [Base Image](#term-base-image) - [Multi-stage Build](#term-multi-stage-build) - [Container Runtime](#term-container-runtime) - [Volume](#term-volume) - [Bind Mount](#term-bind-mount) - [Container Network](#term-container-network) - [.dockerignore](#term--dockerignore) - [Container Orchestration](#term-container-orchestration) ### Kubernetes Configuration - [ConfigMap](#term-configmap) - [Secret](#term-secret) - [ResourceQuota](#term-resourcequota) - [LimitRange](#term-limitrange) ### Kubernetes Core - [Kubernetes (K8s)](#term-kubernetes--k8s-) - [Cluster](#term-cluster) - [Control Plane](#term-control-plane) - [Node](#term-node) - [Pod](#term-pod) - [Namespace](#term-namespace) - [etcd](#term-etcd) - [kube-scheduler](#term-kube-scheduler) - [kube-proxy](#term-kube-proxy) ### Kubernetes Networking - [Service](#term-service) - [ClusterIP](#term-clusterip) - [NodePort](#term-nodeport) - [LoadBalancer](#term-loadbalancer) - [Ingress](#term-ingress) - [Ingress Controller](#term-ingress-controller) ### Kubernetes Reliability - [Liveness Probe](#term-liveness-probe) - [Readiness Probe](#term-readiness-probe) - [Startup Probe](#term-startup-probe) - [Rolling Update](#term-rolling-update) - [Pod Disruption Budget (PDB)](#term-pod-disruption-budget--pdb-) ### Kubernetes Scaling - [HorizontalPodAutoscaler (HPA)](#term-horizontalpodautoscaler--hpa-) - [VerticalPodAutoscaler (VPA)](#term-verticalpodautoscaler--vpa-) - [Cluster Autoscaler](#term-cluster-autoscaler) ### Kubernetes Scheduling - [Taint & Toleration](#term-taint---toleration) - [Node Affinity](#term-node-affinity) ### Kubernetes Security - [RBAC (Role-Based Access Control)](#term-rbac--role-based-access-control-) - [ServiceAccount](#term-serviceaccount) - [NetworkPolicy](#term-networkpolicy) ### Kubernetes Storage - [PersistentVolume (PV)](#term-persistentvolume--pv-) - [PersistentVolumeClaim (PVC)](#term-persistentvolumeclaim--pvc-) - [StorageClass](#term-storageclass) ### Kubernetes Tooling - [Helm](#term-helm) - [Helm Chart](#term-helm-chart) - [kubectl](#term-kubectl) - [kubeconfig](#term-kubeconfig) ### Kubernetes Workloads - [Deployment](#term-deployment) - [ReplicaSet](#term-replicaset) - [StatefulSet](#term-statefulset) - [DaemonSet](#term-daemonset) - [Job](#term-job) - [CronJob](#term-cronjob) - [Init Container](#term-init-container) - [Sidecar Container](#term-sidecar-container) No terms found Try adjusting your search query ## Containers 16 ### Container A lightweight, standalone, executable package that bundles the code, runtime, libraries, and settings needed to run a piece of software, isolated from the host system. #### Example Running an Nginx web server inside a Docker container without installing Nginx on the host. #### Code Snippet ``` 1docker run -d -p 80:80 nginx ``` ### Docker An open platform for building, shipping, and running applications inside containers, providing tooling to create images, manage containers, and interact with registries. #### Example Building a custom Node.js application image using a Dockerfile. #### Code Snippet ``` 1docker build -t myapp:latest . ``` ### Dockerfile A text file containing ordered instructions that Docker follows to automatically build a container image, layer by layer. #### Example A Dockerfile that sets up a Python Flask application with all its dependencies. #### Code Snippet ``` 1```dockerfile2FROM python:3.11-slim3WORKDIR /app4COPY requirements.txt .5RUN pip install -r requirements.txt6COPY . .7CMD ["python", "app.py"]8``` ``` ### Docker Image A read-only, layered template used to create containers. Built from a Dockerfile and stored in a registry. Each layer represents a set of filesystem changes. #### Example Pulling the official PostgreSQL 15 image from Docker Hub to use as a base. #### Code Snippet ``` 1docker pull postgres:15 ``` ### Docker Layer Each instruction in a Dockerfile creates a read-only layer in the resulting image. Layers are cached and reused across builds to improve performance. #### Example A RUN apt-get install layer is cached and not rebuilt if the instruction has not changed. #### Code Snippet ``` 1```dockerfile2RUN apt-get update && apt-get install -y curl3# This becomes one cached layer4``` ``` ### Docker Compose A tool for defining and running multi-container Docker applications using a YAML file, allowing you to start all services with a single command. #### Example Running a web app, a Redis cache, and a PostgreSQL database together with docker compose up. #### Code Snippet ``` 1```yaml2services:3 web:4 image: myapp5 ports:6 - "8080:8080"7 db:8 image: postgres:159``` ``` ### Container Registry A storage and distribution service for Docker images, allowing teams to push, pull, version, and share images across environments. #### Example Pushing a built image to Amazon ECR after a successful CI pipeline run. #### Code Snippet ``` 1docker push 123456789.dkr.ecr.us-east-1.amazonaws.com/myapp:latest ``` ### Docker Hub The default public container registry provided by Docker, hosting official images for popular software as well as user-published images. #### Example Pulling the official Node.js image from Docker Hub as a base for a custom application. #### Code Snippet ``` 1docker pull node:18-alpine ``` ### Base Image The starting point for a Dockerfile, specified in the FROM instruction. It provides the OS and runtime environment on top of which your application is built. #### Example Using node:18-alpine as a base image to keep the final image small. #### Code Snippet ``` 1FROM node:18-alpine ``` ### Multi-stage Build A Dockerfile technique that uses multiple FROM instructions to separate the build environment from the final runtime image, reducing the size of the produced image. #### Example Compiling a Go binary in one stage and copying only the binary into a minimal final image. #### Code Snippet ``` 1```dockerfile2FROM golang:1.21 AS builder3RUN go build -o app .4 5FROM alpine:3.186COPY --from=builder /app /app7CMD ["/app"]8``` ``` ### Container Runtime The low-level software responsible for running containers on a host, managing their lifecycle including starting, stopping, and isolating them using OS primitives. #### Example containerd and CRI-O are common container runtimes used by Kubernetes nodes. #### Code Snippet ``` 1systemctl status containerd ``` ### Volume A mechanism for persisting data generated by and used by Docker containers, existing outside the container lifecycle so data survives container restarts or deletion. #### Example Mounting a named volume to persist a PostgreSQL database across container restarts. #### Code Snippet ``` 1docker run -v pgdata:/var/lib/postgresql/data postgres:15 ``` ### Bind Mount A type of Docker mount that maps a specific file or directory on the host machine directly into a container, enabling live file sharing between host and container. #### Example Mounting a local source code directory into a development container to enable hot reloading. #### Code Snippet ``` 1docker run -v $(pwd):/app myapp:dev ``` ### Container Network A virtual network that Docker creates to allow containers to communicate with each other and with the outside world, with different drivers supporting different topologies. #### Example Creating a bridge network so that a web container can reach a database container by name. #### Code Snippet ``` 1docker network create mynetwork ``` ### .dockerignore A file that specifies patterns of files and directories to exclude from the Docker build context, reducing build time and preventing secrets from being included in images. #### Example Excluding node\_modules and .env files from the Docker build context. #### Code Snippet ``` 1```2node_modules3.env4*.log5.git6``` ``` ### Container Orchestration The automated management of containerized workloads across multiple hosts, handling deployment, scaling, networking, and self-healing of containers at scale. #### Example Kubernetes automatically restarting a failed container and rescheduling it on a healthy node. #### Code Snippet ``` 1kubectl get pods --watch ``` ## Kubernetes Configuration 4 ### ConfigMap A Kubernetes object used to store non-sensitive configuration data as key-value pairs, decoupling configuration from container images. #### Example Storing application feature flags and environment-specific settings in a ConfigMap. #### Code Snippet ``` 1```yaml2apiVersion: v13kind: ConfigMap4metadata:5 name: app-config6data:7 LOG_LEVEL: "info"8 MAX_CONNECTIONS: "100"9``` ``` ### Secret A Kubernetes object that stores sensitive data such as passwords, tokens, and TLS certificates, keeping them separate from application code and pod specs. #### Example Storing a database password as a Kubernetes Secret and injecting it as an environment variable. #### Code Snippet ``` 1kubectl create secret generic db-secret --from-literal=password=mypassword ``` ### ResourceQuota A Kubernetes policy that limits the aggregate resource consumption per namespace, controlling how much CPU, memory, and object count a team can use. #### Example Limiting the staging namespace to a maximum of 8 CPU cores and 16Gi of memory. #### Code Snippet ``` 1```yaml2apiVersion: v13kind: ResourceQuota4spec:5 hard:6 requests.cpu: "8"7 requests.memory: 16Gi8``` ``` ### LimitRange A Kubernetes policy that sets default and maximum resource requests and limits for containers in a namespace, preventing unbounded resource consumption. #### Example Setting a default memory limit of 512Mi for all containers in the dev namespace. #### Code Snippet ``` 1```yaml2apiVersion: v13kind: LimitRange4spec:5 limits:6 - default:7 memory: 512Mi8 type: Container9``` ``` ## Kubernetes Core 9 ### Kubernetes (K8s) An open-source container orchestration platform originally developed by Google that automates deploying, scaling, and managing containerized applications across clusters. #### Example Running a production web application across 10 nodes with automatic scaling and self-healing. #### Code Snippet ``` 1kubectl cluster-info ``` ### Cluster A set of machines (nodes) that run containerized applications managed by Kubernetes, consisting of at least one control plane and one or more worker nodes. #### Example A production EKS cluster with 3 control plane nodes and 10 worker nodes across 3 availability zones. #### Code Snippet ``` 1kubectl get nodes ``` ### Control Plane The set of components that manage the overall state of the Kubernetes cluster, including scheduling workloads, maintaining desired state, and serving the API. #### Example The control plane detects that a pod has crashed and schedules a replacement on a healthy node. #### Code Snippet ``` 1kubectl get componentstatuses ``` ### Node A physical or virtual machine in a Kubernetes cluster that runs workloads. Each node contains a kubelet, container runtime, and kube-proxy. #### Example A worker node running five pods across two namespaces. #### Code Snippet ``` 1kubectl describe node my-node ``` ### Pod The smallest deployable unit in Kubernetes, consisting of one or more tightly coupled containers that share the same network namespace, IP address, and storage volumes. #### Example A pod containing an application container and a sidecar container for log shipping. #### Code Snippet ``` 1```yaml2apiVersion: v13kind: Pod4metadata:5 name: my-pod6spec:7 containers:8 - name: app9 image: myapp:latest10``` ``` ### Namespace A Kubernetes mechanism for isolating groups of resources within a single cluster, providing scope for names, resource quotas, and access control policies. #### Example Using separate namespaces for dev, staging, and production environments in the same cluster. #### Code Snippet ``` 1kubectl create namespace staging ``` ### etcd A distributed key-value store used by Kubernetes as its primary backing store for all cluster state and configuration data. #### Example All Kubernetes objects, including pods, services and configmaps, are persisted in etcd. #### Code Snippet ``` 1etcdctl get /registry/pods/default/my-pod ``` ### kube-scheduler The Kubernetes control plane component responsible for assigning newly created pods to nodes, based on resource requirements, constraints, and policies. #### Example The scheduler placing a pod with 4 CPU requests on a node that has sufficient available capacity. #### Code Snippet ``` 1kubectl -n kube-system get pod -l component=kube-scheduler ``` ### kube-proxy A network component that runs on each node and maintains network rules to forward traffic destined for Services to the correct pod endpoints. #### Example kube-proxy updating iptables rules when a new pod is added to a Service endpoint. #### Code Snippet ``` 1kubectl -n kube-system get pod -l k8s-app=kube-proxy ``` ## Kubernetes Networking 6 ### Service A Kubernetes abstraction that provides a stable network endpoint for accessing a set of pods, with built-in load balancing and DNS-based service discovery. #### Example Exposing a backend deployment internally to other services using a ClusterIP Service. #### Code Snippet ``` 1```yaml2apiVersion: v13kind: Service4spec:5 selector:6 app: backend7 ports:8 - port: 809 targetPort: 808010``` ``` ### ClusterIP The default Kubernetes Service type that exposes the service on an internal cluster IP, making it reachable only from within the cluster. #### Example A database service exposed only internally to application pods in the same cluster. #### Code Snippet ``` 1```yaml2spec:3 type: ClusterIP4 ports:5 - port: 54326``` ``` ### NodePort A Kubernetes Service type that exposes the service on a static port on each node's IP, making it accessible from outside the cluster via any node's IP and that port. #### Example Exposing a development application externally on port 30080 for testing. #### Code Snippet ``` 1```yaml2spec:3 type: NodePort4 ports:5 - port: 806 nodePort: 300807``` ``` ### LoadBalancer A Kubernetes Service type that provisions an external cloud load balancer and assigns a public IP, forwarding traffic into the cluster's pods. #### Example Exposing a production web application publicly using a LoadBalancer Service on AWS EKS. #### Code Snippet ``` 1```yaml2spec:3 type: LoadBalancer4 ports:5 - port: 4436``` ``` ### Ingress A Kubernetes API object that manages external HTTP and HTTPS access to services, providing routing rules, TLS termination, and virtual hosting in one place. #### Example Routing traffic to different microservices based on URL path using an Nginx Ingress controller. #### Code Snippet ``` 1```yaml2apiVersion: networking.k8s.io/v13kind: Ingress4spec:5 rules:6 - host: app.example.com7 http:8 paths:9 - path: /api10 backend:11 service:12 name: api-service13``` ``` ### Ingress Controller A pod that runs inside the cluster and implements the Ingress rules, acting as a reverse proxy and load balancer for incoming traffic. Common options include Nginx and Traefik. #### Example Installing the Nginx Ingress Controller via Helm to handle all incoming HTTP traffic. #### Code Snippet ``` 1helm install ingress-nginx ingress-nginx/ingress-nginx ``` ## Kubernetes Reliability 5 ### Liveness Probe A Kubernetes health check that determines if a container is still running correctly. If the probe fails, Kubernetes restarts the container automatically. #### Example A liveness probe hitting /healthz every 10 seconds and restarting the container if it fails 3 times. #### Code Snippet ``` 1```yaml2livenessProbe:3 httpGet:4 path: /healthz5 port: 80806 initialDelaySeconds: 107 periodSeconds: 108``` ``` ### Readiness Probe A Kubernetes health check that determines if a container is ready to accept traffic. Pods that fail the readiness probe are removed from Service endpoints until they recover. #### Example A readiness probe preventing traffic from reaching a pod while it initializes its database connection. #### Code Snippet ``` 1```yaml2readinessProbe:3 httpGet:4 path: /ready5 port: 80806 initialDelaySeconds: 57 periodSeconds: 58``` ``` ### Startup Probe A Kubernetes health check that gives slow-starting containers extra time to initialize before liveness and readiness probes take over, preventing premature restarts. #### Example A startup probe allowing a legacy Java application up to 3 minutes to start before checking health. #### Code Snippet ``` 1```yaml2startupProbe:3 httpGet:4 path: /healthz5 port: 80806 failureThreshold: 307 periodSeconds: 108``` ``` ### Rolling Update A Kubernetes Deployment strategy that gradually replaces old pod replicas with new ones, keeping enough replicas available throughout the update that there is no downtime. #### Example Deploying a new application version by replacing pods one at a time while maintaining availability. #### Code Snippet ``` 1```yaml2strategy:3 type: RollingUpdate4 rollingUpdate:5 maxSurge: 16 maxUnavailable: 07``` ``` ### Pod Disruption Budget (PDB) A Kubernetes policy that limits the number of pods of a replicated application that can be simultaneously unavailable during voluntary disruptions such as node drains. #### Example Keeping at least 2 replicas of a web service available during a node upgrade. #### Code Snippet ``` 1```yaml2apiVersion: policy/v13kind: PodDisruptionBudget4spec:5 minAvailable: 26 selector:7 matchLabels:8 app: my-web9``` ``` ## Kubernetes Scaling 3 ### HorizontalPodAutoscaler (HPA) A Kubernetes resource that automatically scales the number of pod replicas in a Deployment based on observed CPU utilization or custom metrics. #### Example Automatically scaling a web deployment from 2 to 20 replicas based on CPU usage exceeding 60%. #### Code Snippet ``` 1kubectl autoscale deployment my-app --cpu-percent=60 --min=2 --max=20 ``` ### VerticalPodAutoscaler (VPA) A Kubernetes component that automatically adjusts the CPU and memory resource requests and limits of containers based on historical usage patterns. #### Example Using VPA to right-size a memory-hungry container that was over-provisioned at initial deployment. #### Code Snippet ``` 1```yaml2apiVersion: autoscaling.k8s.io/v13kind: VerticalPodAutoscaler4spec:5 updatePolicy:6 updateMode: Auto7``` ``` ### Cluster Autoscaler A Kubernetes component that automatically adjusts the number of nodes in a cluster when pods cannot be scheduled due to resource constraints or nodes are underutilized. #### Example The Cluster Autoscaler adding a new node to AWS EKS when pending pods cannot be scheduled. #### Code Snippet ``` 1kubectl -n kube-system logs deployment/cluster-autoscaler ``` ## Kubernetes Scheduling 2 ### Taint & Toleration A Kubernetes mechanism where taints are applied to nodes to repel pods, and tolerations are applied to pods to allow them to schedule onto tainted nodes. #### Example Tainting GPU nodes so only ML workloads with the correct toleration can be scheduled on them. #### Code Snippet ``` 1```yaml2tolerations:3- key: "gpu"4 operator: "Equal"5 value: "true"6 effect: "NoSchedule"7``` ``` ### Node Affinity A Kubernetes scheduling rule that constrains which nodes a pod can be scheduled onto based on node labels, offering more expressive rules than node selectors. #### Example Scheduling data-intensive pods exclusively onto nodes in the us-east-1a availability zone. #### Code Snippet ``` 1```yaml2affinity:3 nodeAffinity:4 requiredDuringSchedulingIgnoredDuringExecution:5 nodeSelectorTerms:6 - matchExpressions:7 - key: topology.kubernetes.io/zone8 operator: In9 values: [us-east-1a]10``` ``` ## Kubernetes Security 3 ### RBAC (Role-Based Access Control) A Kubernetes authorization mechanism that regulates access to cluster resources based on the roles assigned to users or service accounts. #### Example Granting a CI/CD service account permission to deploy to the production namespace only. #### Code Snippet ``` 1```yaml2apiVersion: rbac.authorization.k8s.io/v13kind: Role4rules:5- apiGroups: ["apps"]6 resources: ["deployments"]7 verbs: ["get", "update"]8``` ``` ### ServiceAccount A Kubernetes identity assigned to pods, allowing them to authenticate to the Kubernetes API and interact with cluster resources according to their RBAC permissions. #### Example Assigning a ServiceAccount to a pod that needs to list other pods in the same namespace. #### Code Snippet ``` 1```yaml2apiVersion: v13kind: ServiceAccount4metadata:5 name: app-service-account6 namespace: production7``` ``` ### NetworkPolicy A Kubernetes resource that controls the traffic flow at the IP address or port level between pods and external endpoints, acting as a firewall within the cluster. #### Example Restricting a database pod to only accept connections from pods with the label app=backend. #### Code Snippet ``` 1```yaml2apiVersion: networking.k8s.io/v13kind: NetworkPolicy4spec:5 ingress:6 - from:7 - podSelector:8 matchLabels:9 app: backend10``` ``` ## Kubernetes Storage 3 ### PersistentVolume (PV) A piece of storage in the cluster provisioned by an administrator or dynamically by a StorageClass, with a lifecycle independent of any pod that uses it. #### Example A 100Gi EBS volume provisioned as a PersistentVolume for a PostgreSQL StatefulSet. #### Code Snippet ``` 1```yaml2apiVersion: v13kind: PersistentVolume4spec:5 capacity:6 storage: 100Gi7 accessModes:8 - ReadWriteOnce9``` ``` ### PersistentVolumeClaim (PVC) A request for storage by a user that consumes a PersistentVolume, specifying size and access mode. Kubernetes binds the PVC to a suitable PV automatically. #### Example A pod requesting 10Gi of storage via a PVC that Kubernetes binds to an available PV. #### Code Snippet ``` 1```yaml2apiVersion: v13kind: PersistentVolumeClaim4spec:5 accessModes:6 - ReadWriteOnce7 resources:8 requests:9 storage: 10Gi10``` ``` ### StorageClass A Kubernetes resource that defines different classes of storage with their provisioner and parameters, enabling dynamic provisioning of PersistentVolumes on demand. #### Example A StorageClass backed by AWS gp3 EBS volumes that auto-provisions storage when a PVC is created. #### Code Snippet ``` 1```yaml2apiVersion: storage.k8s.io/v13kind: StorageClass4provisioner: ebs.csi.aws.com5parameters:6 type: gp37``` ``` ## Kubernetes Tooling 4 ### Helm A package manager for Kubernetes that uses charts to define, install, and upgrade complex Kubernetes applications, simplifying repeatable deployments. #### Example Installing a full Prometheus + Grafana monitoring stack with a single Helm install command. #### Code Snippet ``` 1helm install monitoring prometheus-community/kube-prometheus-stack ``` ### Helm Chart A collection of files that describe a related set of Kubernetes resources, packaged together with configurable values to enable reusable and versioned application deployments. #### Example A Helm chart for a web application with configurable replicas, image tag, and ingress hostname. #### Code Snippet ``` 1```2mychart/3 Chart.yaml4 values.yaml5 templates/6 deployment.yaml7 service.yaml8``` ``` ### kubectl The command-line tool for interacting with Kubernetes clusters, allowing you to deploy applications, inspect resources, and manage cluster operations. #### Example Using kubectl to view all pods across all namespaces and their current status. #### Code Snippet ``` 1kubectl get pods --all-namespaces ``` ### kubeconfig A YAML file that stores cluster connection details, credentials, and context configurations, used by kubectl to authenticate and communicate with Kubernetes clusters. #### Example Switching between a staging and production cluster context using kubectl. #### Code Snippet ``` 1kubectl config use-context production-cluster ``` ## Kubernetes Workloads 8 ### Deployment A Kubernetes resource that declaratively manages a set of identical, stateless pod replicas, supporting rolling updates, rollbacks, and scaling. #### Example Scaling a web application from 3 to 10 replicas during peak traffic. #### Code Snippet ``` 1kubectl scale deployment my-app --replicas=10 ``` ### ReplicaSet A Kubernetes resource that ensures a specified number of pod replicas are running at any given time. Usually managed by a Deployment rather than directly. #### Example A ReplicaSet maintaining exactly 3 running replicas of a web server pod. #### Code Snippet ``` 1kubectl get replicasets ``` ### StatefulSet A Kubernetes workload resource for managing stateful applications, providing stable pod identities, ordered deployment, and persistent storage per pod. #### Example Running a 3-node Kafka cluster using a StatefulSet with persistent volumes for each broker. #### Code Snippet ``` 1```yaml2apiVersion: apps/v13kind: StatefulSet4metadata:5 name: kafka6spec:7 serviceName: kafka8 replicas: 39``` ``` ### DaemonSet A Kubernetes resource that ensures a copy of a specific pod runs on every node (or a subset of nodes) in the cluster, commonly used for logging and monitoring agents. #### Example Deploying a Fluentd log collector pod on every node using a DaemonSet. #### Code Snippet ``` 1```yaml2apiVersion: apps/v13kind: DaemonSet4metadata:5 name: fluentd6``` ``` ### Job A Kubernetes resource that creates one or more pods to execute a finite task and ensures they run to successful completion, then terminates. #### Example Running a database migration script as a Kubernetes Job before deploying a new application version. #### Code Snippet ``` 1```yaml2apiVersion: batch/v13kind: Job4metadata:5 name: db-migration6``` ``` ### CronJob A Kubernetes resource that creates Jobs on a repeating schedule defined using cron syntax, useful for periodic batch tasks like backups or report generation. #### Example Running a nightly database backup job at 2:00 AM using a CronJob. #### Code Snippet ``` 1```yaml2apiVersion: batch/v13kind: CronJob4spec:5 schedule: "0 2 * * *"6``` ``` ### Init Container A specialized container that runs to completion before app containers in a pod start, used for setup tasks such as waiting for a dependency or initializing config files. #### Example An init container waiting for a database to be ready before the main application container starts. #### Code Snippet ``` 1```yaml2initContainers:3- name: wait-for-db4 image: busybox5 command: ['sh', '-c', 'until nc -z db 5432; do sleep 2; done']6``` ``` ### Sidecar Container A helper container that runs alongside the main application container in the same pod, augmenting or supporting its functionality without modifying the main image. #### Example A Fluentd sidecar container collecting and forwarding logs from the main application container. #### Code Snippet ``` 1```yaml2containers:3- name: app4 image: myapp5- name: log-shipper6 image: fluentd7``` ``` ## Comments Was this useful? ## You might also enjoy More posts on similar topics [![Kubernetes Advanced](/_astro/hero.CRGMYrKF_ZUVOtB.webp)](/glossary/post/kubernetes-advanced) ## [Kubernetes Advanced](/glossary/post/kubernetes-advanced) - [Mohammad Abu Mattar](/authors/mohammad-abu-mattar) - [Kubernetes](/glossary/categories/kubernetes) - [Platform](/glossary/categories/platform) This glossary covers the advanced Kubernetes terminology platform engineers rely on: scheduling, networking, storage, security, extensibility, and the workload controllers that keep applications runni [#Kubernetes](/glossary/tags/kubernetes)[#Orchestration](/glossary/tags/orchestration)[#Platform](/glossary/tags/platform)+5 tags [read more](/glossary/post/kubernetes-advanced) [![DevOps Basics](/_astro/hero.CWNG2jIz_Z24wybF.webp)](/glossary/post/devops-basics) ## [DevOps Basics](/glossary/post/devops-basics) - [Mohammad Abu Mattar](/authors/mohammad-abu-mattar) - [Devops](/glossary/categories/devops) This glossary covers foundational terms used in DevOps and cloud engineering, spanning containerization, orchestration, infrastructure as code, CI/CD pipelines, observability, and deployment strategie [#Basics](/glossary/tags/basics)[#Ci cd](/glossary/tags/ci-cd)[#Kubernetes](/glossary/tags/kubernetes)+2 tags [read more](/glossary/post/devops-basics) [![CI/CD & Automation](/_astro/hero.DTGfmUcf_Fms81.webp)](/glossary/post/ci-cd-and-automation) ## [CI/CD & Automation](/glossary/post/ci-cd-and-automation) - [Mohammad Abu Mattar](/authors/mohammad-abu-mattar) - [Devops](/glossary/categories/devops) A quick-reference glossary of the terms you meet when automating builds, tests, and deployments: pipeline anatomy, test gates, and release strategies like canary and blue-green. [#Ci cd](/glossary/tags/ci-cd)[#Automation](/glossary/tags/automation)[#Pipelines](/glossary/tags/pipelines) [read more](/glossary/post/ci-cd-and-automation) [![Linux Server Administration](/_astro/hero.v7WMsrAk_Z6S9HG.webp)](/glossary/post/linux-server-administration) ## [Linux Server Administration](/glossary/post/linux-server-administration) - [Mohammad Abu Mattar](/authors/mohammad-abu-mattar) - [Linux](/glossary/categories/linux) This glossary covers essential Linux server administration concepts: system architecture, user management, networking, storage, process management, performance tuning, and security hardening. [#Linux](/glossary/tags/linux)[#Server](/glossary/tags/server)[#Administration](/glossary/tags/administration)+1 tags [read more](/glossary/post/linux-server-administration) [![Networking Fundamentals](/_astro/hero.CcGlr5M6_2oFVtq.webp)](/glossary/post/networking-fundamentals) ## [Networking Fundamentals](/glossary/post/networking-fundamentals) - [Mohammad Abu Mattar](/authors/mohammad-abu-mattar) - [Networking](/glossary/categories/networking) - [Fundamentals](/glossary/categories/fundamentals) This glossary covers the core networking concepts every developer, DevOps engineer, and system administrator should know: how data is layered and addressed, and how it gets routed across the internet. [#Networking](/glossary/tags/networking)[#Tcp ip](/glossary/tags/tcp-ip)[#Dns](/glossary/tags/dns)+5 tags [read more](/glossary/post/networking-fundamentals) 5 related posts