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๐Ÿงฉ Chhoti Cheezein โ€” Jargon Buster

Bade concepts to modules me hain. Ye page un chhoti cheezon ke liye hai jinhe log assume kar lete โ€” ek shabd jo beech me aata aur dimaag atak jaata. Har term: ek line "kya" + ek analogy/example. Assume nothing.

๐Ÿ’ก Tip: poore handbook me in me se kai terms pe hover karoge to seedha meaning dikhega (dotted underline waale).

๐Ÿ” Security ke chhote shabd

  • Vulnerability โ€” software ke code me ek security hole/kamzori jise attacker exploit kar sake (data churana, control lena). Ghar me khuli khidki. Severity hoti: Low ยท Medium ยท High ยท Critical.
  • CVE โ€” Common Vulnerabilities and Exposures. Kisi ek known vulnerability ko diya gaya public unique ID โ€” CVE-2014-0160. Har hole ka Aadhaar number, taaki duniya same hole ko same naam se refer kare.
  • CVSS / Severity โ€” vulnerability kitni khatarnak hai uska score (0โ€“10) โ†’ Low/Medium/High/Critical.
  • Trivy โ€” ek scanner (CLI binary) jo image/code/IaC me known CVEs dhundhta. CI me build ke baad, push se pehle chalta (shift-left gate).
  • SBOM โ€” Software Bill of Materials. Ek ingredient list โ€” image/app me kaunse packages+versions hain. CVE track + supply-chain ke liye.
  • Secret โ€” sensitive value (password, API key, token). Git me kabhi plaintext nahi โ€” secret-manager/K8s Secret me.
  • Credentials โ€” kisi cheez tak pahunchne ki "chaabi" (token, key, cert). Cluster ki credentials = kubeconfig / ServiceAccount.

๐Ÿ“ฆ Containers & images ke chhote shabd

  • CLI โ€” Command-Line Interface. Terminal me command type karke chalne wala tool (git, docker, kubectl), GUI click nahi.
  • Binary โ€” ek single executable file jo seedha chalta, koi extra install nahi (Windows .exe jaisa). Go tools (Trivy, kubectl, terraform) single-binary hote โ€” no dependencies.
  • Daemon โ€” background me chalta-rehne wala process (Docker daemon, SSH daemon). (alag cheez: DaemonSet = K8s object neeche.)
  • Image โ€” app + saari dependencies ka immutable sealed box (recipe se bana). Disk pe rehta.
  • Container โ€” image ka running instance โ€” ek isolated Linux process. Image = class, Container = object.
  • Layer โ€” Dockerfile ke har instruction se bana ek filesystem diff; layers stack ho ke image banti (union FS + copy-on-write).
  • Registry โ€” images ka warehouse (DockerHub, ECR, GHCR). CI push karta, kubelet pull karta.
  • Tag vs Digest โ€” tag = mutable label (:v1, :latest) ยท digest = immutable hash (@sha256:โ€ฆ). Prod me SHA/digest, :latest kabhi nahi.
  • Artifact โ€” pipeline ka output jo aage use ho (built image, binary, test report, package).

โ˜ธ๏ธ Kubernetes ke chhote shabd

  • Node โ€” cluster ki ek machine (EC2/VM) jaha pods chalte.
  • Pod โ€” K8s ki smallest unit โ€” ek (ya kuch) container(s) ka wrapper. Actual "worker".
  • API server โ€” cluster ka front door โ€” har kubectl/deploy isi se hota.
  • etcd โ€” cluster ka database โ€” saara desired-state (sach) yahin store.
  • Control plane โ€” cluster ka dimaag: apiserver + etcd + scheduler + controller-manager.
  • kubelet โ€” har node pe floor-worker โ€” pods ko actually chalata + health report karta.
  • kube-proxy โ€” Service networking โ€” ClusterIP โ†’ sahi pod ke liye kernel me rules likhta (DaemonSet).
  • CNI โ€” Container Network Interface. Pod networking dene wala plugin (Calico, Flannel, Cilium) โ€” pod IPs + cross-node routing + NetworkPolicy.
  • Deployment โ€” "mujhe N replicas chahiye, kahin bhi" โ€” stateless apps.
  • ReplicaSet โ€” Deployment ke andar wala jo actually N pods maintain karta.
  • DaemonSet โ€” "har node pe exactly 1 pod" โ€” node-level agents (CNI, kube-proxy, log/metrics collectors). Har floor pe ek chowkidar.
  • StatefulSet โ€” fixed naam (postgres-0) + apna PVC โ†’ data pod-death ke baad bhi survive (DB ke liye).
  • Service โ€” pods ka stable address (ClusterIP) โ€” pod IP badle, Service ka fixed. Reception desk.
  • Ingress โ€” L7 HTTP router โ€” ek entry point se host/path ke hisaab se sahi Service tak. (Resource = rules; Controller = nginx jo enforce karta.)
  • Namespace โ€” cluster ke andar alag folder/floor โ€” isolation ke liye.
  • ConfigMap / Secret โ€” config pod ke bahar โ€” ConfigMap khula, Secret hidden (base64, encryption nahi).
  • PVC โ€” PersistentVolumeClaim โ€” pod ka personal locker (disk) jo pod-death se nahi jaata.
  • Probe โ€” pod ki sehat-check: readiness (traffic lene layak?) ยท liveness (zinda?) ยท startup.
  • HPA โ€” Horizontal Pod Autoscaler โ€” load pe pods badhaao/ghatao (metrics-server chahiye).
  • PDB โ€” PodDisruptionBudget โ€” drain/upgrade ke time kitne pods hamesha zinda rahein.
  • RBAC โ€” Role-Based Access Control โ€” kaun kya kar sakta (permissions). Access card.
  • kubeconfig โ€” ek file: cluster ka endpoint + admin credentials โ€” isse kubectl cluster se baat karta. Cluster ki chaabi (push model me CI ke paas โ€” bahar).
  • ServiceAccount โ€” pod ki andar-wali identity (+ RBAC). ArgoCD isi se cluster me apply karta โ€” chaabi andar rehti.

๐Ÿ” CI/CD & GitOps ke chhote shabd

  • CI โ€” Continuous Integration โ€” code aate hi test + build (GitHub Actions, Jenkins).
  • CD โ€” Continuous Delivery/Deployment โ€” usse deploy tak le jaana (ArgoCD).
  • Runner โ€” wo machine (VM) jispe CI ke jobs actually chalte. (GitHub Actions = tool; runner = uski machine.)
  • Pipeline โ€” CI/CD ke ordered steps (test โ†’ build โ†’ scan โ†’ push โ†’ deploy).
  • Manifest โ€” desired-state likhi hui YAML (Deployment/Service etc.) jo cluster me apply hoti.
  • GitOps โ€” Git = single source of truth; ek agent (ArgoCD) Git ko dekh ke cluster ko match karta (pull).
  • Drift โ€” Git (desired) aur cluster (actual) ka farak โ€” koi ne manually chhed diya. GitOps ise khud theek karta.
  • Push vs Pull โ€” push = CI cluster me deploy karta (chaabi bahar) ยท pull = ArgoCD andar se Git kheench ke apply karta (chaabi andar, secure).

โ˜๏ธ Cloud & infra ke chhote shabd

  • IaC โ€” Infrastructure as Code โ€” infra ko code (Terraform) se banana, click se nahi.
  • State (tfstate) โ€” Terraform ki diary โ€” kya-kya bana rakha hai ka record. S3 me rakho, kabhi Git me nahi.
  • VPC โ€” Virtual Private Cloud โ€” cloud me tumhara private network.
  • IAM โ€” Identity and Access Management โ€” cloud me kaun kya kar sakta (users/roles/permissions).
  • ELB / Auto Scaling โ€” Load Balancer (traffic baant) / instances khud badhao-ghatao.
  • Region / AZ โ€” Region = geographic area (Mumbai) ยท AZ = us region ka ek data-center. Multi-AZ = fault-tolerance.
  • CDN โ€” Content Delivery Network โ€” users ke paas cache-servers (edge) โ€” content ki copy waha, load origin se door.

Koi shabd chhoot gaya jo tumhe atkเคพya? Bata do โ€” yahin add ho jaayega. Ye page hamesha "assume nothing" rahega.