Reliability Review Process

This process governs how engineering teams evaluate system changes for potential reliability impact before deployment. It applies to any modification that could affect service availability, performance, or error rates, whether in code, configuration, infrastructure, or operational procedures.

When to Initiate a Reliability Review

A review must begin when a change introduces risk to system stability. This includes modifications to:

• Service dependencies
• Resource allocation settings
• Error handling logic
• Configuration parameters that affect behavior
• Infrastructure scaling rules
• Deployment strategies or rollback mechanisms

The review starts during the planning phase, before any code is committed or infrastructure is provisioned. It must complete at least 24 hours prior to deployment.

Preparing for Review

Before scheduling a review, gather all relevant information about the proposed change:

• System architecture diagrams showing affected components
• Service level objective definitions (SLOs)
• Error budget consumption rates
• Historical failure patterns
• Impact estimates for latency, throughput, and error rates

Document these in a shared review document. Include specific metrics to monitor post-deployment.

Scheduling the Review

Use your team's established calendar system to schedule a 60-minute meeting. The meeting must include:

• Change author
• System owners
• Reliability engineers
• Operations representatives
• Any stakeholders with operational impact

Set the meeting in a shared calendar with recurring invitees and clear agenda items.

Conducting the Review

Initial Assessment

Begin by reviewing the change against established reliability criteria:

1. Does it introduce new failure modes?
2. Are dependencies properly handled?
3. Is error recovery adequately implemented?
4. How does it affect system resource usage?
5. What are the rollback implications?

Risk Scoring

Assign a numeric risk score from 1 to 5, where:

• 1: Minimal impact, no new components
• 2: Low impact, minor changes to existing systems
• 3: Medium impact, moderate complexity or new dependencies
• 4: High impact, significant system changes or new critical paths
• 5: Critical impact, major architectural changes or global service modifications

Use this score to determine review depth and follow-up requirements.

Technical Analysis

Examine each affected component for:

• Resource limits (CPU, memory, disk, network)
• Timeout configurations
• Retry policies
• Circuit breaker settings
• Data consistency guarantees
• Failure recovery paths

For each component, document expected behavior under normal conditions and under stress.

Review Documentation Requirements

The final review document must contain:

• Change description with scope
• Risk assessment and score
• Component analysis with failure modes
• Monitoring plan with alert thresholds
• Rollback strategy
• Post-deployment success criteria

This document serves as the basis for the final approval decision.

Approval Decision Process

Review Outcome Categories

After evaluation, categorize the change as:

1. Approved - Change may proceed with documented monitoring
2. Conditional Approval - Change requires additional steps before deployment
3. Rejected - Change must be redesigned or deferred

Approval Authority

Only authorized personnel can approve changes. This includes:

• Senior engineers with reliability responsibility
• System owners with operational authority
• Reliability team members with voting rights

The decision must be recorded in the review document with timestamp and approver signature.

Monitoring Requirements

Pre-deployment Checks

Before deployment, verify:

• All monitoring alerts are configured
• Alert thresholds are appropriate for change impact
• Rollback procedures are documented and tested
• Resource limits are validated against expected usage

Post-deployment Validation

Monitor the following within 24 hours of deployment:

• Service availability metrics
• Error rates and error patterns
• Latency distributions
• Resource utilization trends
• SLO compliance

Common Failure Modes

Silent Configuration Changes

Configuration changes that appear simple may silently affect reliability:

• Database connection pool settings
• Timeout values in external service calls
• Retry count adjustments for critical operations
• Memory allocation parameters

These changes often pass code review but introduce runtime instability.

Dependency Misunderstanding

Teams sometimes misjudge the impact of dependency changes:

• Assumptions about external service behavior
• Incorrect handling of error responses
• Underestimating resource consumption of new components
• Ignoring circuit breaker behavior in cascading failures

Monitoring Gaps

Insufficient monitoring creates blind spots:

• Missing alert coverage for new failure modes
• Inappropriate threshold settings
• Lack of correlation between related metrics
• Absence of business logic indicators in metrics

Review Process Validation

Checklist Compliance

Reviewers must verify:

• All risk factors are considered
• Component analysis is comprehensive
• Monitoring plan is complete and actionable
• Rollback strategy is clearly defined
• Approval criteria are met

Escalation Path

If issues arise during review:

1. Document all concerns in the review document
2. Escalate to senior reliability engineers
3. Schedule additional discussion if needed
4. Reassess risk score if new information emerges

Post-Review Follow-up

Success Criteria Verification

Within 72 hours of deployment:

• Verify that all monitored metrics meet expected ranges
• Confirm that SLOs are maintained
• Validate that rollback procedures function correctly
• Document any unexpected behavior or performance issues

Review Closure

Close the review process by:

• Updating the review document with post-deployment results
• Archiving the document for future reference
• Recording lessons learned for process improvement
• Notifying stakeholders of final outcome

Change Management Integration

The reliability review process integrates with standard change management workflows. The review must be completed before any change enters the production deployment pipeline. This integration ensures that reliability considerations are part of every system modification.

Configuration Example

Example review document structure:

Change Summary:
- Description: [brief description]
- Risk Score: [1-5]
- Review Date: [date]
- Approver: [name]

Component Analysis:
[component name]:
- Failure Modes: [list]
- Monitoring Requirements: [list]
- Resource Impact: [description]

Monitoring Plan:
- Alert Thresholds: [details]
- Metrics to Track: [list]
- Duration: [time period]

Rollback Strategy:
- Steps: [list]
- Recovery Time: [estimate]
- Dependencies: [list]

Technical Considerations

Error Budget Integration

Each change consumes error budget based on risk score. Changes with higher scores consume more budget, reducing available error allowance for subsequent deployments.

Alert Configuration Validation

Ensure all alerts are properly configured:

• Appropriate thresholds
• Correct notification channels
• Clear alert messages
• Correlation with relevant metrics

Resource Planning Verification

Confirm that resource allocation accounts for:

• Normal operating conditions
• Peak load scenarios
• Error handling overhead
• Graceful degradation capabilities

Process Compliance

Teams must maintain records of all reliability reviews. These documents serve as audit trails and learning resources. The process applies to all system modifications, regardless of team or component ownership.

The review process ensures that reliability considerations are systematically integrated into engineering workflows, reducing the likelihood of production incidents caused by overlooked impacts.

This page was rewritten on 16 October 2026. It replaced a templated version that was not specific to its own title. How these pages are written and checked. If anything here is wrong, tell us at [email protected] and we will correct it.