Outage Postmortem Template and Checklist for IT Admins (adapted from the X/Cloudflare/AWS incidents)

When a major provider outage hits: your fastest path from chaos to clarity

Hook: If you’ve been burned by X, Cloudflare, or AWS outages in recent months, you know the pain: fragmented telemetry, conflicting provider statements, stressed stakeholders, and weeks of unclear follow-ups. This postmortem template and checklist is a reusable, provider-focused toolset ops teams can execute the moment an external outage touches your stack — to collect verifiable evidence, do a blameless root cause analysis, and communicate clearly.

Why a provider-focused postmortem matters in 2026

Late 2025 and early 2026 saw a rise in high-impact, cross-provider events: routing-table anomalies, edge cache misconfigurations, and cascading control-plane failures. Teams have moved to multi-cloud and edge-first architectures to gain resilience, but that increases the need for targeted, reproducible postmortems when a platform provider or CDN has a problem. You must be able to:

• Prove what failed inside your control and what was external
• Collect telemetry that stands up to audits and legal review
• Communicate accurate impact and timelines to execs and customers
• Derive precise action items to reduce repeat risk

What’s new in 2026 — trends that shape this template

• Edge & multi-cloud growth: More traffic and critical logic run on CDNs and edge providers, so outages often manifest at the edge.
• BGP and routing incidents: Increased attention to BGP hijacks and RPKI validation — add routing telemetry early. See strategies for channel failover and edge routing.
• AI-driven anomaly detection: ML-based observability tools can surface anomalies but require preserved raw telemetry for verification; pair this with augmented oversight for supervised review.
• Legal and compliance needs: Customers and regulators expect signed evidence (checksums/timestamps) after outages — treat chain-of-custody like any other compliance artifact and see guidance on chain of custody in distributed systems.
• Adoption of blameless culture: Industry-wide emphasis on blameless postmortems and clear remediation tracking.

Quick play: Immediate 15-minute checklist (what to do first)

1. Contain impact: Isolate affected services, switch traffic if runbooks allow (traffic-shift to healthy regions), enable static failovers.
2. Preserve evidence: Start logging to immutable storage and tag logs with a unique incident ID (example: INCIDENT-20260116-XCF-AWS-01).
3. Collect provider statements: Snapshot provider status pages (Cloudflare, AWS Service Health, X/Twitter status) and take time-synced screenshots.
4. Notify stakeholders: Publish a short status update (see templates below) to execs, SREs, and customer ops teams.
5. Start the timeline: Record detection time, first alert source, and first mitigation action in a shared doc.

Reusable postmortem template (copy + paste and adapt)

Use this skeleton to produce consistent, auditable incident reports. Keep the tone blameless and data-focused.

1. Executive Summary

• Incident ID: INC-YYYYMMDD-PROV-##
• Impact summary (1–2 sentences): services, regions, customer-facing features
• Start/End time (UTC) and duration
• Severity (P0/P1) and outage classification (provider outage / internal failure / hybrid)
• Overall customer impact (est. % of traffic/users affected)

2. Scope & Impact

• List of services, APIs, and regions affected
• Downtime metrics: MTTD, MTTR, customers affected, revenue-impact estimate
• Known side effects (data loss, duplicate transactions, degraded performance)

3. Detection

• How was the issue detected? (synthetic monitor, customer report, provider status)
• First alert timestamp and source
• Telemetry snapshots: list log files, traceroutes, packet captures with filenames and checksums

4. Timeline (chronological)

Provide a granular timeline. Example structure:

00:00:00 - 2026-01-16T10:29:33Z - Synthetic check failed: us-east-1 / api.example.com (check-id: synth-1234)
00:02:10 - 2026-01-16T10:31:43Z - PagerDuty alert triggered; on-call acknowledged
00:04:00 - 2026-01-16T10:33:33Z - Traceroute shows hop failure at Cloudflare edge 2606:4700:...; capture saved to pcap/trace-20260116-1033.pcap
...

5. Root Cause Analysis (RCA)

Separate the direct cause from contributing factors and systemic causes. Use the "5 whys" but focus on evidence:

• Direct cause: e.g., Cloudflare edge cache invalidation bug causing 502s for a subset of PoPs.
• Contributing factors: misconfigured health checks, missing fallback DNS TTLs, insufficient synthetic coverage.
• Systemic issues: lack of cross-provider BGP monitoring, inadequate documented runbook for cross-provider incidents.

6. Mitigation & Recovery

• Immediate mitigations and timestamps
• Workarounds used (traffic-shift, blackhole, DNS rollback)
• Why the mitigations worked/didn’t work

7. Remediation & Preventative Actions

• Short-term action items (0–7 days)
• Mid-term (1–3 months): runbooks, synthetic test expansions, SLA changes with provider
• Long-term (3–12 months): architecture changes, multi-CDN adoption, BGP/RPKI validation

8. Verification & Measurement

How will you verify fixes? Add exact success criteria and measurement plans:

• Increase synthetic coverage to 3 probes per major region with 1-minute intervals
• Establish 99.95% availability SLO for API endpoint measured over 30 days
• Deploy BGP monitoring via RIPE Atlas and ThousandEyes with automated alerting

9. Appendices

• Raw telemetry artifacts: pcap files, traceroute logs, synthetic monitor CSVs + checksums
• Provider status snapshots and URLs
• Relevant runbooks and change records

Evidence collection: commands and examples you should run immediately

Collect time-aligned artifacts from your network edges, app servers, and CDN control planes. Save output in an immutable store (S3 with Object Lock) (S3 with Object Lock, or Write-Once storage).

Network & path diagnostics

# traceroute (IPv4 and IPv6)
traceroute -n api.example.com > traces/traceroute-$(date -u +%Y%m%dT%H%M%SZ)-v4.txt
traceroute6 -n api.example.com > traces/traceroute-$(date -u +%Y%m%dT%H%M%SZ)-v6.txt

# mtr (two-minute run)
mtr -r -c 120 -w api.example.com > traces/mtr-$(date -u +%Y%m%dT%H%M%SZ).txt

# dig for DNS evidence
dig +noall +answer api.example.com @8.8.8.8 > traces/dig-$(date -u +%Y%m%dT%H%M%SZ).txt

Packet capture

# tcpdump on the host facing the CDN
sudo tcpdump -w traces/pcap-$(date -u +%Y%m%dT%H%M%SZ).pcap 'host api.example.com and port 443'
# compress and checksum
gzip traces/*.pcap
sha256sum traces/*.pcap.gz > traces/checksums.sha256

For on-the-ground capture hardware and field kits see Portable Network & COMM Kits reviews.

Application-level traces and logs

# Example: download cloudwatch logs for a window using AWS CLI
aws logs filter-log-events --log-group-name /ecs/api --start-time 1705440000000 --end-time 1705443600000 --output json > traces/cloudwatch-api-INC-170544.json
sha256sum traces/cloudwatch-api-INC-170544.json > traces/checksums.sha256

Tip: Include cryptographic checksums and sign artifacts with an organizational GPG key if your legal/compliance posture requires non-repudiation. Guidance on provable artifacts and custody is available in chain-of-custody in distributed systems.

Provider statements vs. local telemetry: how to reconcile conflicts

Providers publish status updates that are useful, but they may be delayed or incomplete. Reconcile by:

1. Correlating timestamps — ensure all telemetry uses synchronized NTP and record offset if any.
2. Comparing synthetic probe failures to provider-identified PoPs/regions in their status update.
3. Cross-checking with internet-wide observability (RIPE Atlas, CAIDA, BGPStream) when routing is implicated; see observability playbooks at Observability for Workflow Microservices.
4. Requesting provider debug artifacts (BGP dumps, edge logs) through formal support channels; record ticket IDs and expected response SLAs.

Blameless communication: status messages and stakeholder templates

Use concise, factual messages and avoid speculation. Below are ready-to-send templates.

Short Slack/status page update (customers)

[INC-20260116-01] We are investigating elevated 502 errors impacting api.example.com for customers in US-East. Root cause appears to be a third-party CDN edge disruption. We are collecting telemetry and will update at 10:45 UTC. (Impact: API errors ~12% of requests; workaround: retry with exponential backoff)

Executive report (email to C-level)

Subject: Incident INC-20260116-01 — Third-party CDN edge outage impacting API calls Summary: Between 10:29–11:18 UTC we observed service degradation due to a Cloudflare edge disruption. We have mitigated via regional traffic-shift; full service restoration completed at 11:18 UTC. Initial revenue impact estimate: low to medium. Postmortem is in progress; expected delivery: 72 hours. — SRE Lead

Checklist for a thorough provider-focused postmortem

Use this checklist to make sure nothing is missed.

1. Incident ID created and shared
2. Immutable storage for artifacts (object lock / vault) set up
3. Synchronized time across systems (NTP check)
4. Traceroutes, pcaps, dig, and mtr collected from multiple regions
5. Provider status snapshots + ticket IDs stored
6. Stakeholder updates posted at regular intervals
7. Blameless RCA drafted with clear evidence mapping
8. Action items assigned with owners and due dates
9. Verification plan with metrics and success criteria
10. Postmortem published and shared in company and customer channels

Measuring downtime and impact (metrics that matter)

Track these metrics so your postmortem quantifies impact and improvement:

• MTTD (Mean Time to Detect): when the team first became aware
• MTTR (Mean Time to Repair): time from detection to full functional recovery
• Downtime minutes: total customer-facing minutes lost
• Error budget consumed: percent of SLO error budget used by the incident
• Customer tickets and escalations: volume and severity

Formula examples:

MTTD = detection_time - actual_start_time
MTTR = full_recovery_time - detection_time
Downtime_minutes = sum(duration of degraded minutes across affected regions)

Examples & mini-case study (anonymized)

In late 2025, a SaaS company observed elevated 503 errors across Europe. Their postmortem revealed:

• Root cause: a Cloudflare configuration change that incorrectly set origin health checks to require an extra header, failing origin pool healthchecks in certain PoPs.
• Contributing: synthetic monitors were region-limited and did not run against the failing PoPs; DNS TTLs were low but not low enough for rapid rollback.
• Actions: added global synthetic checks, implemented a CDN-config review checklist for change windows, and negotiated a runbook with provider support for future incidents.

Outcome: On-call detection time decreased 40% and similar incidents were prevented by staged change rollouts and preflight validations.

Advanced strategies & future-proofing

• Multi-CDN fallback: Use an active-passive CDN setup for critical endpoints and run routine failover drills; see channel & edge routing approaches at Channel Failover, Edge Routing & Winter Resilience.
• Provable telemetry: Store artifact checksums and GPG-sign them to support legal/regulatory audits — follow chain-of-custody best practices.
• Chaos and provider drills: Run observable chaos experiments targeting edge-cache and routing to validate runbooks alongside augmented oversight workflows.
• Automate artifact collection: Use incident automation (PagerDuty, VictorOps, Rundeck/Orchestration) to run the collection commands above when an alert triggers.
• Provider SLA alignment: Ensure SLAs map to your SLOs and include credits/penalties for cascading outages; this ties back into observability and cost playbooks.

Postmortem governance: timelines and accountability

Establish these deadlines for actionable incident governance:

• Initial public status update: within 15 minutes of detection
• Internal RCA draft: within 48–72 hours
• Final postmortem (with assigned action items): within 7 business days
• Verification & closure: evidence that remediation worked within 30–90 days

Closing with a blameless mantra

"Assume complexity, not malice." Use the postmortem to learn, not to punish. The goal is to reduce systemic risk across people, process, and technology.

Actionable takeaways (do these now)

1. Implement the Immediate 15‑minute checklist as an automated incident runbook.
2. Start collecting telemetry artifacts with checksums and store them immutably.
3. Adopt the reusable postmortem template and schedule a 72-hour RCA draft rule.
4. Expand global synthetic probes and BGP monitoring to detect edge and routing issues earlier; see observability playbooks at Observability for Workflow Microservices.

Resources & tools (2026-ready)

• Telemetry & monitoring: Datadog, Grafana Cloud, New Relic, AWS X-Ray
• Network observability: RIPE Atlas, ThousandEyes, BGPStream
• Artifact storage: AWS S3 Object Lock, GCP Archive, Azure Immutable Blob
• Incident automation: PagerDuty, VictorOps, Rundeck

Call to action

Take this template and run a provider outage drill within the next 30 days. Start by automating the immediate evidence collection commands above and run a simulated CDN-edge outage. If you want, download our ready-to-run incident automation scripts and a fillable postmortem template from filesdownloads.net to accelerate adoption. For cloud docs and visual editing of runbooks, consider Compose.page for Cloud Docs to keep timelines and diagrams in sync with your postmortem.

Related Reading

• Advanced Strategy: Observability for Workflow Microservices
• Chain of Custody in Distributed Systems: Advanced Strategies for 2026 Investigations
• Advanced Strategy: Channel Failover, Edge Routing and Winter Grid Resilience
• Future-Proofing Publishing Workflows: Modular Delivery & Templates-as-Code
• Design Review: Compose.page for Cloud Docs — Visual Editing Meets Infrastructure Diagrams