Menene Services a Kubernetes, kuma menene bambanci tsakanin ClusterIP, NodePort, da LoadBalancer?

Question

IT Interview Practice · Accepted Answer

**Service** yana ba da tantancewar hanyar sadarwa mai ƙarko (IP na kama-da-wane da suna DNS) ga *tarin Pod* da aka zaɓa ta labels. Tunda Pod na ɗan lokaci ne kuma suna canja IP, Service shine adireshin mai dorewa da abokan ciniki ke amfani da shi, kuma yana **load-balance** a kan Pod masu lafiya da ke bayansa.

## Me ya sa Services suke wanzuwa

```text
Pod suna zuwa suna tafiya (sabon IP kowane lokaci). Abokan ciniki suna buƙatar ENDPOINT MAI ƘARKO.
Service:
  → yana zaɓar Pod ta label  (selector: app=web)
  → yana samun IP na kama-da-wane na dindindin + suna DNS (web.default.svc.cluster.local)
  → yana load-balance buƙatun a kan Pod masu daidaituwa da ke READY
```

## Manyan nau'ikan Service uku

```text
ClusterIP    (tsoho)   → ana isa gare shi KAWAI cikin cluster
                          don sadarwar pod-to-pod / service na cikin gida
NodePort               → yana buɗe port a kan KOWANE node (30000-32767)
                          zirga-zirgar waje na buga nodeIP:nodePort → Service → Pods
LoadBalancer           → yana samar da load balancer na cloud na waje
                          yana ba da IP na jama'a wanda ke tuƙa zuwa Service
```

```text
       Internet
          │
   ┌──────┴───────┐
   │ LoadBalancer │  (LB na cloud, IP na jama'a)  ← don service na jama'a
   └──────┬───────┘
          │
   ┌──────┴───────┐
   │  NodePort    │  (node:30080)            ← yana fito da shi a kan kowane node
   └──────┬───────┘
          │
   ┌──────┴───────┐
   │  ClusterIP   │  (10.96.x.x, na cikin gida)  ← tushen ginin
   └──────┬───────┘
       Pods (app=web)
LoadBalancer yana ginuwa a kan NodePort, wanda ke ginuwa a kan ClusterIP.
```

## ClusterIP (na cikin gida)

```yaml
apiVersion: v1
kind: Service
metadata:
  name: web
spec:
  type: ClusterIP          # tsoho; za a iya barin sa
  selector:
    app: web               # yana daidaita Pod masu label app=web
  ports:
    - port: 80             # port na Service
      targetPort: 8080     # port na container
```

Sauran Pod suna isa gare shi ta DNS: `http://web` (namespace guda) ko `http://web.default.svc.cluster.local`.

## NodePort da LoadBalancer

```yaml
# NodePort — kowane node yana saurara a kan nodePort ya kuma tura zuwa Service
spec:
  type: NodePort
  selector: { app: web }
  ports:
    - port: 80
      targetPort: 8080
      nodePort: 30080      # na zaɓi; 30000-32767
---
# LoadBalancer — cloud yana samar da LB na waje da IP na jama'a
spec:
  type: LoadBalancer
  selector: { app: web }
  ports:
    - port: 80
      targetPort: 8080
```

```bash
kubectl get svc            # duba nau'ika, cluster IP da external IP
kubectl get endpoints web  # ainihin IP na Pod da ke bayan Service
```

## Me ya sa yake da muhimmanci

Services su ne yadda hanyar sadarwa ke aiki a Kubernetes, don haka fahimtar su da matsayin nau'ika ilimi ne mai mahimmanci, na yau da kullum. Saboda Pod na ɗan lokaci ne kuma suna samun sabon IP a kowane sake ƙirƙira, ba za ka iya nuna abokan ciniki kai tsaye zuwa IP na Pod ba; **Service** yana warware wannan ta hanyar bayar da **IP na kama-da-wane da suna DNS masu ƙarko** a gaban tarin Pod da aka zaɓa ta label, da kuma **load-balance** zirga-zirga a kan Pod masu Ready kawai. Nau'ika uku suna samar da ci gaba na matakai: **ClusterIP** (tsoho) yana ba da adireshin na cikin gida kawai don sadarwar pod-to-pod da service-to-service kuma shine tushen ginin; **NodePort** yana buɗe port na dindindin a kan kowane node don zirga-zirgar waje ta iya isa ga Service; kuma **LoadBalancer** yana ci gaba ta hanyar samar da load balancer na cloud na waje da IP na jama'a — kowane nau'i yana ginuwa a kan wanda ke ƙasa da shi. Sanin wanda za a nema — ClusterIP don zirga-zirgar microservice na cikin gida, NodePort don isar da waje na asali ko saitunan on-prem, LoadBalancer don fito da endpoint na jama'a a kan cloud (kuma, a aikace, Ingress a gaban ClusterIP Services don tuƙawar HTTP) — na tushe ne don tsara yadda ɓangarori ke magana da juna da kuma da duniyar waje. Tunda kusan kowane ainihin workload yana buƙatar haɗi mai ƙarko da load balancing, fahimtar Services da nau'ikansu ilimin hanyar sadarwa ne na tushe na Kubernetes wanda ke bayyana koyaushe a duka tsarawa da gyara kurakurai.

Me ya sa Services suke wanzuwa

Manyan nau'ikan Service uku

ClusterIP (na cikin gida)

NodePort da LoadBalancer

Me ya sa yake da muhimmanci

Tambayoyi masu alaƙa