Rapid Mitigation Checklist When a Top CDN or Cloud Provider Goes Down

Rapid Mitigation Checklist When a Top CDN or Cloud Provider Goes Down

Hook: When a major CDN or cloud provider fails, every minute multiplies customer impact, revenue loss, and escalates support load. This one‑page tactical checklist is a no‑fluff, engineer‑centric runbook for the first hour—triage, stabilize, and buy time for durable remediation.

Why this matters in 2026

Late 2025 and January 2026 saw high‑profile incidents where CDNs and cloud networking services affected large swathes of internet services. Modern architectures are more distributed—edge compute, multi‑CDN, and programmatic DNS—so a single provider failure can ripple faster. Meanwhile, observability has become AI‑driven and SLOs are contractual; the first hour of response is now decisive for both customer trust and regulatory/commercial obligations.

Minutes matter: the goal of hour‑one is to stabilize customer experience, prevent cascading failures, and create safe windows for full failover.

How to use this checklist

This document is organized as a time‑boxed checklist (0–5m, 5–15m, 15–30m, 30–60m) with specific commands, decision points, and communications templates. Print or pin this as a single page in your incident channel and follow sequentially. Avoid performing destructive actions (BGP announcements, wholesale DNS sweeps) without approvals — there are safe alternatives first.

Immediate priorities (What must be true within the first hour)

• Scope & impact identified (services, regions, customers).
• Traffic routing stabilized (cached content served, origin overload prevented).
• Customer communication live and updated every 15 minutes.
• Observability preserved (logs, traces, and key metrics retained).
• Runbook and escalation chain activated.

Minute‑by‑minute Tactical Checklist

0–5 minutes: Stop the bleeding — identify scope and engage

1. Activate incident channel: open an incident bridge (Slack/MS Teams) and invite service owners, SRE, network, security, and on‑call contacts. Post the incident title, start time, and initial hypothesis.
2. Quick scope triage:
   • Check provider status pages (Cloudflare, AWS, Fastly, Akamai). Note timestamped updates.
   • Correlate with your synthetic monitors and real user monitoring (RUM): which endpoints, regions, or clients are failing?
   • Gather immediate error symptoms: 502s, DNS failures, high latency, or partial content missing.
3. Run fast checks (run these commands from multiple locations):
   • HTTP health: curl -I https://yourdomain.example/health -s -S -m 10
   • DNS: dig @8.8.8.8 yourdomain.example +short and dig @1.1.1.1 yourdomain.example
   • Traceroute/mtr: mtr -c 10 -r yourdomain.example or traceroute yourdomain.example
   • Check CDN edge headers: curl -I -H 'Cache-Control: no-cache' https://yourdomain and inspect provider headers.
4. Escalate to provider: open or update your support ticket with provider admin/priority level. Include trace artifacts and timestamps. Use provider incident channels and your account rep.
5. Post first public update to status page and support channels. Keep it brief: "We are aware of an issue affecting X; investigating. Affected services: list. Next update in 15m."

5–15 minutes: Contain and stabilize traffic

1. Prevent origin swamping:
   • Enable or tighten rate limits at the CDN/WAF to stop cache‑bypass storms.
   • Temporarily reject expensive endpoints (search, analytics) via feature flags or WAF rules.
2. Maximize caching:
   • Set edge TTLs where manageable (if provider API is reachable). If provider config is unavailable, use client‑side strategies: increase local browser TTL via headers for static assets.
   • For HTML, return cached fallback pages or a lightweight degraded experience stored in object storage/CDN origin.
3. Direct traffic to alternate paths (if preconfigured):
   • Switch DNS to secondary authoritative nameservers (only if you run multi‑DNS and TTLs permit).
   • Activate prewired multi‑CDN failover via API or DNS steering (example providers: NS1, Cedexis-like steering) — do not create new BGP announcements unless trained staff present.
4. Enable origin‑only mode (careful):
   • If CDN is the failure vector and your origin can absorb traffic, flip to origin direct via alternate CNAME or IPs. Monitor CPU, memory, and connection queue depth closely.
   • If origin is not provisioned for direct public traffic, consider rate‑limiting or progressive rollout to a subset of traffic.
5. Communicate: Send a 15‑minute update describing containment actions and expected next update time.

15–30 minutes: Implement reliable short‑term fixes and protect customers

1. Staged failover:
   • Fail over low‑impact customer segments first (internal, partner traffic) to validate alternate paths.
   • If multi‑region, fail traffic per region to keep unaffected regions online.
2. Switch to degraded UX with graceful fallback:
   • Return cached UI shell + local javascript that indicates degraded mode. Provide clear messaging and minimal functionality (login read‑only, etc.).
3. Preserve observability:
   • Ensure logging agents are not overwhelmed; sample traces if necessary to retain signal. Use agent side‑buffering to disk if cloud logging endpoints are impacted.
   • Tag metrics with incident id and hypothesis for postmortem correlation.
4. Security checks:
   • Validate no misconfig or unexpected rule changes caused the outage. Confirm there is no active DDoS or BGP hijack; use public BGP looking glasses and RPKI validators.
5. Customer updates: Publish a detailed 30‑minute update with severity, affected areas, and mitigation in progress.

30–60 minutes: Harden, converge on durable remediation, and plan recovery

1. Decide recovery strategy and document in the incident timeline:
   • Wait for provider fix and keep mitigations in place, or
   • Execute full failover to secondary provider (DNS/CDN/edge) following tested playbooks.
2. If full failover is chosen:
   • Follow pretested runbooks. Example safe steps: update low TTL DNS records on the authoritative provider you control; update CDN CNAMEs to secondary provider; rotate origin keys if necessary.
   • Throttle the switch: route a small percentage of traffic and validate metrics before expanding to 100%.
3. Protect data integrity:
   • Ensure asynchronous writes and message queues are stable. Do not reprocess queues unless you can deduplicate or confirm idempotency.
4. Stakeholder communications:
   • Send the 60‑minute incident update to customers, sales, legal, and leadership. Include impact, mitigations, and estimated time to next update.
5. Prepare post‑incident actions: preserve logs, create an evidence snapshot (traces, provider responses), and schedule a postmortem meeting within 48 hours.

Quick decision matrix (common scenarios)

• CDN control plane down (control API unreachable): maximize edge caching and implement degraded UX. Avoid major config pushes.
• CDN data plane down (requests fail at edges): redirect to alternate CDN or origin‑direct if origin scale allows.
• DNS provider outage: switch to secondary authoritative DNS if preconfigured; if not, use provider contacts to raise emergency change. Keep TTLs as low as possible in normal operations to reduce this risk.
• BGP/peering incident: coordinate with network team and provider NOC; use public RPKI/BGP tools and lookglass to validate route state before announcement changes.

Commands and snippets engineers will use

Keep these in your incident binder; adapt hostnames and tokens for your environment.

• Check edge response headers:

  curl -I -s https://www.example.com | egrep -i 'server|x-cache|via|cf-ray|fastly|x-edge' -n

• Multi‑resolver DNS check:

  for r in 8.8.8.8 1.1.1.1 9.9.9.9; do echo $r; dig @$r www.example.com +short; done

• Simple HTTP smoke tests from multiple locations (using your infra or third‑party API):

  curl -s -o /dev/null -w '%{http_code} %{time_total}\n' https://www.example.com/health

• BGP/RPKI check (read‑only lookglass):

  # Use public services like RIPE/ARIN looking glass or BGPStream to validate announcements

• Limit traffic at origin (example nginx):

  # Add a simple rate limit to prevent overload
  limit_req_zone $binary_remote_addr zone=one:10m rate=10r/s;
  server {
    location / {
      limit_req zone=one burst=20 nodelay;
    }
  }
  

Communication templates (copy/paste)

Initial public status (0–5m)

"We are investigating reports of degraded service for [service]. Impacted areas: [regions / endpoints]. Our team is engaged and working with the provider. Next update in 15 minutes."

15 / 30 / 60 minute update

"Issue update: [summary of scope]. Actions taken: [containment steps]. Customer impact: [reduced / partial / full outage]. Next update: [time]. If you require support, contact [channel]."

Runbook & process notes (post‑incident)

Within 48 hours complete these actions:

• Full timeline with timestamps and decision owners.
• Root cause hypothesis and evidence matrix (provider statements, packet captures, BGP state).
• SLO/SLA impact calculation and customer outreach plan if thresholds were breached.
• Action items: automation gaps, test failovers, lower DNS TTLs, contract/penalty review with provider.
• Postmortem session: no blame; focus on systemic fixes and testable mitigations. Publish a public summary for affected customers.

Advanced strategies and 2026 trends to reduce future blast radius

• Multi‑CDN and multi‑DNS as standard: in 2026 we see adoption of multi‑provider edge architectures combined with programmable traffic steering and AI‑driven failover decisioning.
• Chaos engineering for WAN: simulate CDN and DNS failures in staging and production to validate runbooks automatically.
• AI‑driven observability: leverage model‑based anomaly detectors that surface provider anomalies early; integrate these with playbook automation to trigger mitigations automatically (throttles, cached fallbacks).
• Contract & runbook SLAs: renegotiate provider contracts to include runbook‑verified playbooks and operational runbooks with direct NOC contacts and RRT (response and remediation time) commitments.
• Immutable fallback UX: store a minimal, fully cached fallback experience in object storage across providers so user experience degrades gracefully during upstream provider failures.

Case snapshot: January 2026 CDN/network disruptions (what we learned)

High‑visibility incidents in January 2026 showed common failure modes: control plane misconfigurations causing mass edge failures, provider peering issues that looked like DNS failures, and cascading effects from aggressive cache bypasses. Teams that succeeded were those with tested secondary DNS, cached UX fallbacks, and clear, practiced incident scripts. The single best defense was prior rehearsal of the exact playbook outlined here.

Quick reference: checklist (one‑page printable)

1. Activate incident channel & assign roles.
2. Run fast checks: curl, dig, traceroute from 3 locations.
3. Open provider ticket; add incident ID to all logs.
4. 15m: Enable caching, rate limits, and degraded UX.
5. 30m: Decide staged or full failover; throttle switch traffic.
6. 60m: Stabilize, preserve data, communicate, and schedule postmortem.

Final actionable takeaways

• Practice the runbook—tabletop drills cut time to containment dramatically.
• Prewire failover options (multi‑DNS, multi‑CDN, prepopulated CNAMEs) so you can execute without creating new dependencies under stress.
• Preserve observability and incident metadata—you cannot investigate what you did not record.
• Communicate early and often—customers tolerate outage if they know you are actively working and have a plan.

Use this checklist as your hour‑one playbook. Keep a printed copy in your on‑call bag, and convert key steps into automated runbook scripts that can be executed with one command. The combination of practiced human workflow and safe automation is the most effective way to protect customer experience when a top CDN or cloud provider goes down.

Call to action

Need a customized hour‑one runbook for your stack? Contact our SRE team for a free incident readiness review, tabletop drill, and a tailored failover playbook that integrates with your multi‑cloud tooling and SLAs.

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