Who Patches the OS When Databases Run on Amazon EC2?
Which responsibility belongs to AWS when a company hosts its databases on Amazon EC2 instances?
Community Insight
It tests the IaaS split of the shared responsibility model — AWS owns the host operating system, virtualization layer and hardware, while the customer owns the guest OS, database engine and data — and the trap is assuming that because the database runs on EC2, AWS also patches the database and its guest OS.
This question tests where the shared responsibility line falls when a database is self-hosted on Amazon EC2 rather than run on a managed service such as Amazon RDS. It establishes that among the listed tasks, operating system patching is the one that sits on the AWS side of the line.
The most common wrong pick is D (operating system installations), on the reasoning that AWS 'provides' the OS through Amazon Machine Images; in the exam model the customer owns everything on the instance from the guest OS upward, so installation and configuration are not AWS tasks.
Community Discussion (36 comments)
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Expert Analysis
Why the Answer Is Correct
Hosting a database on Amazon EC2 is an IaaS deployment, so the responsibility boundary runs beneath the instance: AWS operates and patches the physical hosts, the virtualization layer and the host operating system that the instance runs on. Of the four tasks listed, operating system patching is the only one that touches that AWS-controlled layer, which is why the exam key points to option C. Everything the customer can log into and change — the guest operating system, the database engine, the data and its backups — stays firmly on the customer's side. Read the option the way the blueprint intends it: the OS layer AWS maintains underneath EC2, not the guest OS you administer. That is the same split AWS describes when it says customers are responsible for "patching the guest operating system" while AWS handles the infrastructure beneath it.
Why the Other Options Are Wrong
Option A, database backups, is unambiguously customer work: AWS supplies snapshot and backup tooling, but designing, scheduling, retaining and testing the backup strategy for a self-managed database is the customer's job. Option B, database software patches, is also customer work — with EC2 you choose and run the engine (MySQL, PostgreSQL, Oracle), so minor-version upgrades and security fixes inside the engine are yours, which is exactly the burden Amazon RDS removes. Option D, operating system installations, is the tempting one, but on EC2 the customer owns the OS that lands on the instance: you pick or build the AMI, bootstrap it, harden it and re-install if needed, so installation is not an AWS responsibility. None of A, B or D can be pushed to AWS without breaking the shared responsibility model.
Community Comment Notes
Dacusai raised the strongest objection, arguing that with EC2 "you are responsible for everything, OS, DB software and patching and back ups" and that no option is truly correct — a fair literal reading, since the customer does patch the guest OS. TheFivePips reached the same conclusion while still selecting D, listing each option as "A. Database backups - Customer responsibility" and then treating OS installation as the exception. MBFK and Direction369 both anchored on IaaS, noting that AWS maintains the "Physical hardware Networking Virtualization" layer, while nani12e434 stated plainly that the AWS-side item is "opearting system patches". The split in the thread shows the real trap: learners correctly recite the IaaS boundary and then apply it to the wrong layer of the operating system.
Official Reference
Exam Strategy
For any EC2-based scenario, draw the line immediately below the guest OS: hardware, virtualization and host OS patching belong to AWS, while everything you can log into or configure belongs to you. Then scan the options for the single task that maps to the infrastructure layer rather than to the instance itself.
Frequently Asked Questions
Why isn't database software patching (option B) an AWS responsibility on EC2?
With EC2 you install and administer the database engine yourself, so version upgrades and security fixes inside that engine are customer tasks. Moving to Amazon RDS shifts engine patching to AWS.
Does moving the database from EC2 to Amazon RDS change which option is correct?
Yes. On RDS, AWS takes over the guest OS and database engine patching, so the customer keeps only data, access and backup-schedule responsibilities.
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