Upatikanaji wa juu (HA) inamaanisha kuandaa mifumo ya kuendelea kufanya kazi licha ya kutofaulu — kupitia redundancy, upangaji wa multi-AZ, kurejesha kiotomatiki, na kuondoa alama moja za kufa. Ni lengo la msingi kwa mifumo ya uzalishaji na eneo muhimu la usanifu wa AWS.
Kanuni za msingi za HA
✓ ELIMINATE SINGLE POINTS OF FAILURE — no single component whose failure takes down
the system → redundancy everywhere (multiple instances, AZs, etc.)
✓ Deploy across MULTIPLE AVAILABILITY ZONES — survive an AZ (data center) failure
✓ AUTOMATIC RECOVERY — detect failures and recover/replace automatically (no manual fix)
✓ DECOUPLE components — failures isolated; one component's failure doesn't cascade
