ServiceNow Interview Questions and Answers on Handling Failures in Integrations

1. Network Failures

Examples: DNS resolution issues, connection timeouts, SSL handshake failures.

Mitigation Strategies:

• Retry Mechanism: Implement exponential backoff and retry logic in outbound REST/SOAP calls (GlideHTTPRequest or RESTMessageV2).
• Timeout Settings: Configure appropriate timeout values for outbound integrations.
• Fallback Mechanism: Redirect or retry from alternate endpoints if available.
• Alerting: Log and alert on network exceptions using Event Management or a custom error log table.

2. Node Failures

Examples: One or more nodes in a ServiceNow cluster become unresponsive.

Mitigation Strategies:

• High Availability (HA): ServiceNow's cloud infrastructure already offers HA. Avoid depending on session stickiness.
• Retry Requests: REST API consumers should be designed to retry if a 5xx error is returned.
• State Management: Store transaction states in durable tables rather than in memory or session-specific storage.

3. Service Failures

Examples: REST/SOAP endpoints on external systems are down, or ServiceNow itself is under maintenance.

Mitigation Strategies:

• Health Check APIs: Periodically test the availability of external endpoints before sending bulk data.
• Circuit Breaker Pattern: Temporarily disable calls to failing services and re-enable after a cooldown.
• Error Logging: Track the failure in a custom log table with retry indicators.
• Queueing & Async Processing: Use GlideRecord + Scheduled Jobs / Event Queue to retry failed requests later.

4. Dependency Failures

Examples: External systems, APIs, or plugins are unavailable or returning invalid responses.

Mitigation Strategies:

• Dependency Mapping: Use ServiceNow’s CMDB to document dependencies.
• Fail-Fast on Critical Dependency: Abort early with useful logs if an essential dependency is missing.
• Fallback Defaults: Provide cached or default data when dependencies fail (if safe to do so).
• Error Isolation: Fail only the dependent component, not the entire process.

5. Data Inconsistencies

Examples: Schema mismatches, malformed data, partial updates.

Mitigation Strategies:

• Data Validation Rules: Validate incoming/outgoing payloads with Transform Maps, Data Policies, or Flow Validation logic.
• Checksum or Hash Comparison: Detect data corruption.
• Transaction Management: Roll back or flag incomplete transactions.
• Audit & Reconciliation Jobs: Periodically compare source vs. destination systems.

6. Configuration & Deployment Errors

Examples: Misconfigured endpoints, incorrect credentials, invalid scripts in updates.

Mitigation Strategies:

• CI/CD Validation: Use ATF (Automated Test Framework) and peer reviews during deployment.
• Secure Credential Storage: Use Credential records, not hardcoded values.
• Feature Flags: Toggle integration features without full code deploys.
• Rollback Plan: Maintain update set versions and deploy rollback scripts.

7. Time-Related Issues (Clock Skew, Timeouts)

Examples: Integration depends on timestamps and different systems are out of sync.

Mitigation Strategies:

• NTP Syncing: Ensure all involved systems are time-synced using NTP.
• Time Zone Handling: Always use UTC internally for timestamps.
• Timeout Controls: Set reasonable client and server timeout limits.
• Timestamp Logging: Record integration event times with time zone info for traceability.

Cross-cutting Concerns

• Custom Error Log Table: Centralized logging for all failure types (with fields like Integration Name, Error Type, Payload, Retry Count, Timestamp, etc.).
• Notification Rules: Notify responsible teams via email/SMS/Slack based on failure severity.
• Retry Scheduler: Build a retry engine using Scheduled Jobs or Flow Designer that reads from the error log table.

Below are a few scenarios for handling failures in ServiceNow integrations, designed to ensure that users have a smooth fallback experience even when systems fail. Users can continue with their tasks, sometimes with limited functionality, while being informed about the issue, even when certain integrations or external systems are temporarily unavailable.

• If the ML recommendation engine goes down, display popular items instead.
• If live chat is unavailable, show a “Leave us a message” form.
• If the review service fails, show the product without reviews.
• If the location service fails, display the default location (e.g., user’s last known city).
• If an external API for inventory checking fails, show estimated stock levels.
• If the payment gateway is down, offer an option to retry the payment later.
• If a real-time weather service fails, show a default weather forecast based on the user's region.
• If the authentication service is unavailable, provide an option to reset the password via email.
• If CRM system integration fails, display cached customer data until the sync is restored.
• If the Service Catalog fails to load, show the most commonly used catalog items.
• If document upload fails, allow the user to upload it again later.
• If a social media feed integration fails, display a static message with recent posts.
• If the search service fails, suggest popular or recent searches.
• If email notifications fail, show an on-screen confirmation message.
• If the geolocation service fails, ask the user to manually input their location.
• If the order tracking service fails, display the last known order status.
• If the payment verification system fails, notify the user and suggest retrying later.
• If a third-party authentication service fails, allow the user to log in with an alternate method.
• If the video streaming service fails, provide a fallback to an image or static content.
• If the scheduling service fails, show available slots from the last successful sync.
• If the external payment gateway fails, display a message: "Payment service temporarily unavailable, please try again later."
• If a data import fails, show a user-friendly message like: "Data import is currently unavailable. We’re working to fix it."
• If the reporting service fails to generate a report, offer the option to download a cached version of the last successful report.
• If the file processing service fails, allow the user to manually retry or upload the file again later.
• If the language translation service fails, provide a fallback to the default language for the user interface.
• If an API that checks user privileges fails, allow access to basic functionality with a message saying, "Some features are unavailable at the moment."
• If the real-time chat support system fails, offer an option to submit a support ticket or an alternative contact method.
• If form submission to a back-end service fails, show a message: "There was an issue submitting your form. Please check your information and try again."
• If the content management system (CMS) fails to load, show a message like: "We are unable to retrieve content right now. Please check back later."
• If the search index is unavailable, show a basic keyword search option with popular or suggested terms for the user to explore.