How to Upgrade Cisco ACI Firmware with Minimal Disruption
Short answer
C Select the desired APIC firmware image and choose Upgrade Now so the three-controller cluster upgrades with minimal disruption.
Question
Key Takeaways
Tests the ACI upgrade method and image-selection discipline — you must explicitly pick the validated firmware and trigger Upgrade Now, not let the fabric install whichever image happens to be uploaded most recently.
A Cisco ACI firmware upgrade starts with the APIC cluster, where the engineer selects the intended validated firmware image and chooses Upgrade Now so the controllers roll over without taking the fabric down. This page confirms that selecting the desired firmware and choosing Upgrade Now (C) is the answer, and explains why auto-selecting the newest uploaded image is the trap.
Common mistake: Picking B and letting the fabric use the most recently uploaded firmware, which can push an unintended or unvalidated release into the fabric instead of the image the engineer deliberately chose.
Expert Analysis
Why the Answer Is Correct
In Cisco ACI, the upgrade path begins with the three-node APIC cluster: the engineer selects the specific target firmware image in the controller firmware repository and then chooses Upgrade Now, and the cluster performs the upgrade in a controlled, orchestrated fashion while quorum is preserved. Because the APICs are upgraded first, the fabric keeps its policy and forwarding plane intact, which is what delivers "minimal disruptions" in a fabric with two spines and four leaves that carry bare-metal and storage traffic. Once the APICs are on the new release, the spines and leaves are upgraded in their own maintenance groups so that 1-Gb copper server links and 10-Gb SFP storage links are never lost simultaneously. Option C captures exactly that controlled APIC step, which is why it is the correct answer.
Why the Other Options Are Wrong
Option B is the classic distractor: initiating an upgrade that simply consumes the most recent uploaded firmware removes the engineer's control over which release enters the fabric, so an unvalidated or wrong image can be applied. Option D adds the phrase "as a single group," which implies bundling the whole cluster into one blunt operation rather than the rolling, firmware-selected controller upgrade the fabric orchestrates; the deliberate image selection and Upgrade Now of C is the keyed procedure. Note that option A repeats the same wording as C — in these converted question banks the duplicated stem is a formatting artifact, and the canonical, keyed phrasing of the correct procedure is the one in C. None of the options changes the underlying doctrine that the APIC cluster is upgraded first, then spine and leaf switches in separate groups.
Community Comment Notes
prospio971 argued for B, reasoning that spines and leaves must be upgraded separately for stability and that node roles should drive the grouping — a fair point about switch grouping, but it does not make the auto-selected "most recent uploaded firmware" the right image-selection method. Tamerelsayed simply states "C is correct," and ed27 also voted for C, matching the majority of learners who selected the controlled select-firmware-then-Upgrade-Now route.
Official Reference
This link opens the official vendor documentation in a new tab.
Exam Strategy
For 300-620 upgrade questions, memorize the order — APIC cluster first, then spine and leaf switches in separate maintenance groups — and eliminate any option that lets the fabric pick the firmware for you. Choose the answer that shows the engineer explicitly selecting the validated image and triggering Upgrade Now.
Frequently Asked Questions
Why is letting the fabric use the most recently uploaded firmware (B) wrong here?
Do the spine and leaf switches upgrade together with the APICs?
Community Votes
67% of anonymous learners picked answer C. Votes are pick records left by other test-takers — they are not the verified answer.
Discussion 3 contributions
Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.
From public community threads 3
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prospio971 👍 1 Answered BIt is not C, because Spines and leaves should be upgraded separately to maintain stability. It is B: This method aligns with Cisco ACI best practices, which recommend grouping nodes based on their roles and upgrading them sequentially to maintain redundancy and minimize downtime.
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Tamerelsayed 👍 3C is correct
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ed27 👍 2 Answered CVote for C
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