outagesSREincident-response

Postmortem Playbook: Responding to Simultaneous Outages Across X, Cloudflare, and AWS

uupfiles

2026-01-21

11 min read

A practical step-by-step playbook for responding to simultaneous outages across X, Cloudflare, and AWS, with runbooks and comms templates.

Hook: When X, Cloudflare, and AWS all fail at once, your upload flows and SLAs are on the line

Multi-provider cascading outages are one of the highest-impact incidents for platform teams in 2026. You lose CDN edge routing, DNS resolution, and object storage in a matter of minutes, and your resumable uploads, signed-URL flows, and telemetry all come under pressure. This playbook gives you a practical, battle-tested response for simultaneous outages across X, Cloudflare, and AWS: detection, mitigation, communication, recovery, and postmortem templates you can copy into your runbook today.

Top-level summary (the inverted pyramid)

Key actions now: detect anomaly within 60 seconds, activate multi-provider failover runbook, update external status within 5 minutes, and gather immutable evidence for postmortem. Target recovery time objective (RTO) goals: 15 minutes for customer-visible mitigation, 4 hours for full service recovery, and a postmortem published within 72 hours.

Why this matters in 2026

Late 2025 and early 2026 saw a rise in correlated infrastructure incidents driven by centralized control planes, wider adoption of shared edge providers, and complex service meshes tying CDNs and cloud APIs together. Industry trends such as edge compute consolidation and AI-driven orchestration improve agility but increase systemic risk unless teams adopt explicit multi-provider resilience patterns.

Overview: What a multi-provider cascading outage looks like

Initial symptom: spike in 5xx errors and DNS resolution failures across frontend domains.
Secondary symptoms: CDN health probes fail, origin pull errors intensify, object storage PUT/GET error rates climb, and background worker retries cause queue backlogs.
Impact vector: authentication (OAuth/JWT validation) and signed-URL generation may still work, but delivery fails at the CDN or DNS layer; uploads stall or partially complete.

Detection: Signals and instrumentation

Fast detection is your most effective mitigator. Combine these signals to minimize false positives and detect cascading failures early.

Primary signals to monitor

DNS resolution failures: authoritative lookups failing for your domains and for key providers (cloudflare-dns, amazonaws subdomains)
5xx error surge: sudden jump in 5xx rate above baseline across multiple regions
CDN heartbeat failures: Cloudflare health checks or custom edge probes failing
Cloud provider API errors: AWS S3/STS throttling or 5xx responses
Telemetry gaps: missing metrics and logs from third-party agents (a sign of control-plane issue) — make sure your monitoring stack is tested against provider outages (see monitoring platform review)

Practical detection rules (examples)

If DNS failure ratio across 3 public resolvers exceeds 10% for 60s, mark DNS_alert = true.
If 5xx error rate for production API > 3x baseline for 60s AND CDN pull errors > 5%, escalate to incident commander.
If S3 PUT error rate > 2% for 5 minutes, create storage_alert and run storage mitigation playbook.

sample alert rule
- name: multi_provider_outage
  conditions:
    - dns_failure_ratio > 0.1 for 60s
    - api_5xx_rate > 3x baseline for 60s
  severity: critical
  runbook: multi_provider_failover_playbook

Immediate mitigation (first 0-15 minutes)

Focus on protecting users and stopping cascading damage like retries, billing spikes, and data corruption.

1. Triage and incident commander

Declare a Severity 1 incident if two or more provider signals are failing concurrently.
Assign Incident Commander (IC), Communications Lead, and Engineering Lead within 3 minutes.
Open a dedicated incident room and record start time with an immutable timeline (Slack/Zoom/incident tracker).

2. Apply safety controls

Turn off aggressive client retries to avoid client thundering herd. Push a config flag to clients if supported.
Pause billing-sensitive jobs like transcoding or large background uploads to avoid cost spikes.
Increase logging level for critical flows but stream to an external immutable sink if possible.

3. Fast traffic re-routing

If Cloudflare is impaired but origin and AWS are healthy, temporarily bypass the CDN with a DNS change or use a backup CDN. If AWS region is down, fail over to an alternate region, or to a pre-warmed S3 cross-region replica (pre-warming and cross-region planning explained in hybrid edge strategies).

example dns failover steps
- lower ttl for primary domain to 30s if not already low
- update DNS to point to backup CDN or ALB endpoint
- verify health checks return 2xx

4. Quick origin bypass for uploads

When the CDN is down and users are uploading large files, provide a temporary direct upload endpoint with tight limits and short-lived credentials. Revoke access after recovery and reconcile partial uploads via checksum manifests.

direct upload flow (sketch)
1. client requests upload token from auth service
2. auth service returns short-lived presigned URL pointing to backup S3 bucket
3. client uploads with chunked resumable protocol (eg tus or chunked PUT)
4. server validates checksum and moves object to canonical bucket post-recovery

Communication: internal and external templates

Clear, timely communication reduces customer frustration and keeps stakeholders aligned. Use these templates and timings.

First external status (within 5 minutes)

Status: Investigating a service disruption affecting web uploads and content delivery. We're seeing errors affecting multiple providers including CDN and object storage. Engineering is actively investigating. Next update in 15 minutes.

Internal Slack/War room starter (copy-paste)

INCIDENT START
- incident id: 2026-mm-dd-multi
- start: now
- ic: @name
- comms: @name
- eng lead: @name
- impact: frontend 5xxs, uploads failing, CDN errors
- initial actions: pause client retries, activate backup uploads, update status page

Status page update cadence

Initial: within 5 minutes
Progress: every 15 minutes while unresolved
Resolution: clear summary and next steps within 1 hour of recovery

Mitigation patterns for specific provider failures

Cloudflare or CDN outage

Lower DNS TTL ahead of incidents and maintain an emergency bypass hostname on an alternate CDN or direct-to-origin host.
Use alternate CNAMEs for critical assets like JS and CSS so you can point them to a backup delivery path quickly.
Consider using an edge-agnostic fallback: a global Anycast IP or a selection of geo IPs served by different providers.

AWS regional or S3 outage

Pre-configure cross-region replication and Route 53 failover records with health checks.
Use multi-account architecture for critical buckets; keep IAM roles and STS endpoints available in secondary accounts.
Have an automated 'read-only' degraded mode that switches reads to replicas and pauses writes that require strong consistency.

Gracefully degrade features dependent on the platform (eg social login, embed previews) and queue work for background retry.
Provide fallback UI messaging and avoid blocking the main user flow.

Recovery: steps for 15 minutes to 4 hours

Once the immediate customer-impacting mitigations are in place, focus on full recovery and state reconciliation.

1. Confirm provider status and timeline

Verify official provider status pages and incident channels, but treat them as one input—your telemetry is primary.
Record exact start/stop times from your logs and provider messages for the postmortem timeline.

2. Re-enable systems in controlled phases

Gradually re-enable client retries with exponential backoff and limits.
Restore background jobs in batches and reconcile queues to avoid sudden load spikes.
Monitor error budget burn and scale capacity incrementally.

3. Data integrity and reconciliation

For uploads and object operations you must avoid silent data loss or duplication.

Run checksum validation on objects uploaded during the incident window.
Use audit logs and signed manifests to detect partial uploads and apply server-side assemble or discard policies.
Reconcile billing and quota usage across accounts and regions to ensure customers are not overcharged for failed attempts.

4. Post-recovery verification checklist

All health checks green across regions for at least 30 minutes.
Latency and error rates back to baseline.
Deploy a small canary release to verify end-to-end flows like large-file uploads.
Confirm logs and metrics have been archived to a tamper-evident storage for forensics.

Postmortem: structure and templates

A rapid, blameless postmortem lets you learn and restore confidence. Publish within 72 hours with full timeline and action items.

Postmortem template (copy and adapt)

postmortem title: Multi-provider outage affecting CDN and object storage
incident id: 2026-mm-dd-multi
severity: sev1
start: 2026-mm-dd hh:mm UTC
end: 2026-mm-dd hh:mm UTC
summary: brief one-paragraph description of impact and scope
impact: list of affected endpoints, regions, customers
timeline:
  - timestamp: event and actions taken
root cause: concise RCA
contributing factors: list
mitigations applied: list
long term fixes: action items with owners and due dates
communication: links to status updates and customer notices
lessons learned: short points
status: automated verification and closure criteria

How to write a root cause that stands up to audits

Separation between root cause (the immediate technical fault) and contributing factors (process, dependencies, assumptions).
Use logs, packets, and signed timestamps as evidence. Cite provider messages and internal telemetry.
List verification steps that will demonstrate the fix works in production.

Runbook snippets you should commit to source control

Store playbooks as executable runbooks where possible, and use guardrails to avoid operator errors.

Sample runbook snippet for DNS failover

runbook: dns_failover
conditions:
  - Cloudflare_health_check_failed == true
steps:
  - set dns ttl to 30s
  - change A/CNAME to backup endpoint 'backup.example-cdn.example'
  - monitor for 2xx from 3 global probes
  - if no success within 10m rollback and escalate
owner: network-eng

Sample runbook snippet for object storage failover

runbook: s3_failover
conditions:
  - s3_put_error_rate > 0.02 for 5m
steps:
  - enable replica bucket write access
  - switch presigned url generator to replica bucket
  - throttle incoming uploads to 20 rps per region
  - reconcile object list post-incident
owner: storage-eng

Advanced strategies and 2026 trends to adopt

Looking ahead, adopt these advanced resilience strategies that gained traction in 2025-2026.

Multi-control-plane orchestration: Use orchestration that can run across multiple CDNs and clouds rather than rely on single-vendor control planes.
Immutable auditing: Store incident logs and signed manifests in an immutable ledger or WORM storage for compliance and forensics.
AI-assisted incident triage: Use AI-assisted incident triage models trained on your own incident corpus to prioritize remediation steps and reduce MTTR. But always apply human-in-the-loop checks.
Chaos engineering focused on third-party failures: Run exercises that simulate CDN and cloud control-plane failures, not just your code failures.

Performance targets and data-driven KPIs

Set measurable goals so you can track improvement:

Mean time to detect (MTTD): target < 60s for multi-provider anomalies.
Mean time to mitigate (MTTM): target < 15 minutes to customer-visible mitigation.
Mean time to recovery (MTTR): target < 4 hours for full service recovery.
Postmortem publication: within 72 hours, with 100% of action items assigned.

Real-world example: Jan 2026 correlated outage lessons

In January 2026, multiple providers experienced correlated disruptions that manifested as DNS and CDN failures. Teams documenting those incidents highlighted common pitfalls: low DNS TTLs not preconfigured, missing cross-region copies of critical buckets, and overly aggressive retry logic that amplified the outage. Teams that had pre-warmed backup endpoints and automated fallback saw much lower customer impact.

Checklist: Pre-incident hardening (what to do before it happens)

Configure cross-region replication and test failover monthly.
Maintain sub-5m DNS TTL options and a documented backup DNS plan.
Keep a backup CDN account or alternate delivery mechanisms.
Implement resumable client upload protocols and server-side assembly with idempotent manifests.
Run chaos tests that specifically target third-party control-plane failures.
Store runbooks in git and ensure on-call know them and practice them quarterly.

Final takeaways and next steps

Multi-provider outages are not just technical events; they are organizational stress tests. The faster you can detect, the more calmly you can mitigate, and the more transparently you can communicate, the less damage they will do to customers and trust. This playbook prioritizes customer-visible mitigation first, safe recovery second, and evidence-backed postmortems to learn and prevent recurrence.

Actionable next steps (copy into your sprint)

Audit DNS TTLs and create an emergency bypass hostname.
Implement a direct-upload backup flow using short-lived presigned URLs and resumable protocol.
Add multi-provider chaos tests to your CI pipeline.
Commit the communication templates and postmortem template to your incident repo.

Call to action

Ready to harden your file delivery and storage flows against multi-provider outages? Start by cloning the included runbook snippets into your incident playbook repo and schedule a 90-minute tabletop this week with your SRE, platform, and comms teams. If you want a vetted template tuned for large-file upload services, download our incident runbook bundle or contact our engineering team for a resilience review.

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