Yadda za ka sami sakewa mara saituwa?

Question

Accepted Answer

**Sakewa mara saituwa** yana nufin fitar da sabon sifofin sanarwa ba tare da bugatarwa ta yaya ga mai amfani — aikace-aikacen ya kasance akwai kudu jiya. Samun shi yana buƙatar hanyoyin sanarwa masu tunani, canja masu juna daidai, dukan lafiya, da sakin tsiratarwa masu kirki na bukattun bakin jiya.

## Abin da sakewa mara saituwa ke buƙatarwa

```text
GOAL: deploy a new version with NO user-facing downtime (always-available service):
  → never take the whole service offline to deploy
  → always have healthy instances serving while updating others
  → handle in-flight requests gracefully (don't drop them mid-request)
→ Combine several techniques (below).
```

## Mahimmancin hanyoyi

```text
✓ DEPLOYMENT STRATEGY — rolling, blue-green, or canary (never all-at-once downtime):
  → rolling: update instances gradually (others keep serving)
  → blue-green: switch traffic to the new environment instantly
✓ LOAD BALANCER + HEALTH CHECKS → route traffic only to healthy/ready instances;
  new instances join only when READY (readiness checks)
✓ GRACEFUL SHUTDOWN → draining: stop sending new requests to an instance, let it FINISH
  in-flight requests, THEN stop it (handle SIGTERM) → no dropped requests
✓ BACKWARD-COMPATIBLE changes → old and new versions coexist during the rollout
  (API and DATABASE compatibility — expand-contract migrations)
```

## Kalubalen bayyananniya

```text
⚠️ Schema changes during zero-downtime deploys are the hard part (old + new code run
   together): use BACKWARD-COMPATIBLE migrations (expand-contract / parallel change):
   add new schema → migrate → remove old in a LATER deploy → never break the running version
```

## Dalilin da ya sa haka mahaɗi

Wajen fahimta yadda ake samun sakewa mara saituwa yana da mahimmanci ga ilimin ƙananan matakin gida saboda **ci gaba da kasua a lokacin sanarwa yana da mahimmanci ga tsarin aiki da yawa na sauti**, don haka yana da ƙarfi don sadowa mai aminci.

Tsarin da yawa dole ne ya kasance akwai lokaci 24/7, don haka sanarwa ba tare da bugatarwa ga mai amfani (sakewa mara saituwa) yana da mahimmanci — dakin saman aiki don sanarwa bai yarda da shi ba saboda irin tsaraffai, musamman da yadda CI/CD ke sararewa da sakarancin sanarwa.

Wajen fahimta abin da sakewa mara saituwa **buƙatar** (mai kome nuɗar jiya gida gida, komai samu matakai masu lafiya suna aiki yayin ɗaka wasu, da kulawar bakin jiya na kirki) yana tsara burin sa.

Wajen fahimta **mahimmancin hanyoyi** waɗanda suke haɗa don samun shi — amfani da **hanyoyin sanarwa** waɗanda suke guje wa buɗewacin gida-duka (sargawa, blue-green, canary), **dalan jiya masu haɗin gida/shirye-shirye** (aiki jiya zuwa matakai masu lafiya kawai, don sabbin matakai ba su karɓi jiya ba kuma sabon-sabon matakai ba su shiga sai an shirya su), **kirki sanye-sanye/ɓargewa** (tsatsar sabon bakin jiya ga matakai, bari ya gama bakin jiya na bukattun bakin jiya, sannan tsatsa shi — don ba a jefar jiya a tsakiyar jiya, buƙa abun da ya dace na SIGTERM), da **canja masu juna daidai** (don tsohuwa da sabon sifofin suna kasua a lokacin saita) — ƙarfo na kasua.

A mahimmanci, wajen fahimta **kalubalen bayyananniya** (canja fasalin dabaru ita ce saurin alaka don sakewa mara saituwa saboda tsohuwa da sabon gida suna gudu tare, buƙa canja masu juna daidai na faɗawa-ɓangare) tana haɗa zuwa ilimin sadarwa da ake buƙata don sakewa na gida mara saituwa.

Wajen haɗa da juna, hanyoyin nan suna ba da damar sanarwa ci gaba ba tare da bugatarwa mai gida yaya.

Saida ci gaba da kasua yana da mahimmanci ga tsarin aiki da yawa na sauti kuma CI/CD yana sanarwa sau da yawa, kuma sakewa mara saituwa yana buƙatar haɗa hanyoyin sanarwa, dukan lafiya, kirki sanye-sanye, da musamman canja masu juna daidai (bayyananniya), wajen fahimta yadda ake samun sakewa mara saituwa yana da mahimmanci ga ilimin ƙananan matakin gida don sadowa mai aminci — ƙarfi mai mahimmanci don kasua komai kudu, yana nuna sophisikeshon na aiki da aka buƙata don ƙananan matsayi saida sanarwa zuwa sauti ba tare da bugatarwa ga mai amfani.