How to fix App Runner deployment failed health check
| Service | AWS App Runner |
|---|---|
| Cloud | Amazon Web Services (AWS) |
| Guide type | Procedure |
| Skill level | Intermediate to advanced |
| Time | 15 - 60 minutes depending on account size |
If you hit How to fix App Runner deployment failed health check on AWS App Runner in production, the steps below are the path most teams take in 2026. None of them require opening a support case unless your environment has a paid-tier dependency that AWS owns.
What how to fix app runner deployment failed health check actually involves on AWS App Runner
This task on App Runner is one of the more searched operational topics on AWS in the last 12 months. The procedure below is the path that works in a current AWS account with default IAM and standard VPC config.
The rest of this page is the structured fix path. Start with diagnose, then remediation, then the automation options so you do not have to do this by hand the next time it surfaces. Verify and safety sections at the end are the discipline that keeps the fix from regressing in production.
Spot the symptom
Start by capturing the exact AWS error string. The AWS Console truncates messages in popups, but CloudTrail keeps the full record under errorMessage and errorCode. The camelCase error code (e.g. AccessDenied, InsufficientInstanceCapacity, ConditionalCheckFailedException) is the thing you grep for in AWS re:Post and StackOverflow, not the human-readable sentence next to it. Paste the code into the re:Post search bar in quotes and you will usually land on at least one AWS-staff-verified answer within the first three results.
Check CloudWatch Logs for the calling service. Lambda, ECS, EKS, Step Functions, API Gateway, and most managed services write detailed traces to CloudWatch Logs under predictable log group names. Use CloudWatch Logs Insights with fields @timestamp, @message | filter @message like /ERROR/ | sort @timestamp desc | limit 50 to surface the most recent failures.
Reproduce the failure with the AWS CLI in --debug mode. The full SigV4 request payload it emits, plus the exact endpoint URL it resolved to, is what AWS Support uses to verify policy, region, or parameter issues without you having to share IAM credentials. Save the debug output to a file with aws ... --debug 2> debug.log and you can search it for the failed aws.request entry.
Solution-focused remediation path
For IAM and STS issues, the timing matters. STS sessions can take up to 60 seconds to propagate after creation. The first call right after assume-role can fail with a permission error even when the policy is correct. Add a small retry with backoff before treating the first failure as definitive.
If quotas are suspect, the Service Quotas console shows current usage and the active limit side by side. Request increases through Service Quotas, not through Support tickets - quota dashboard requests usually approve faster (often within minutes for soft limits) and they are auditable in CloudTrail. Set up Service Quotas + CloudWatch alarms at 80 percent usage so you get notified before you hit the wall.
If networking is suspect, use VPC Reachability Analyzer. It is the only tool that simulates the full ENI-to-ENI path including security groups, NACLs, route tables, and VPC endpoint policies in one call. Manual trace is slower and misses transitive issues. The analyzer charges $0.10 per analysis - cheaper than a 30-minute call with your network team.
Automate this fix so you do not do it twice
Wire the fix into EventBridge for self-healing
If the failure mode is recurring, automate the remediation instead of the diagnosis. EventBridge Scheduler or rules that watch CloudWatch Events for the specific error code can invoke a Lambda that runs the same fix you would run by hand. The Lambda must be idempotent (re-running it on already-healthy resources must be a no-op) and must emit a CloudWatch metric so you can track how often the auto-fix fires. A spike in auto-fix invocations is itself a signal worth alerting on.
# EventBridge rule pattern (JSON)
{ "source": ["aws.app"], "detail-type": ["AWS API Call via CloudTrail"], "detail": { "errorCode": ["AccessDenied", "ThrottlingException"] }
}Automate the fix with the AWS CLI
The CLI one-liner pattern for AWS App Runner operations is roughly: aws app describe-... --query ... to read state, aws app modify-... --no-dry-run to apply the change, and aws app describe-... --query ... again to verify. Wrap it in a shell script that sets a region variable at the top and exits on first error with set -euo pipefail so a partial run does not leave the account in a half-fixed state.
# Template - replace placeholders with your account specifics
export AWS_REGION=us-east-1
export AWS_PROFILE=prod
aws app describe-... --query 'Resources[?Status==`FAILED`].[Id,Reason]' --output table
aws app modify-... --resource-id RESOURCE_ID --no-dry-run
aws app describe-... --resource-id RESOURCE_ID --query 'Status'Automate the fix with Python and boto3
For anything you do more than twice, write a small Python script. The boto3 pattern below uses paginators (so it does not blow up on accounts with thousands of resources), explicit region binding, and a dry-run flag that defaults to True. Keep the script under 100 lines; if it grows beyond that, you are building a tool and should put it behind a Lambda with proper logging.
import boto3, sys
DRY_RUN = '--apply' not in sys.argv
client = boto3.client('app', region_name='us-east-1')
paginator = client.get_paginator('describe_...')
for page in paginator.paginate(): for item in page.get('Items', []): if item.get('Status') == 'FAILED': if DRY_RUN: print(f'[dry-run] would fix {item["Id"]}') else: client.modify_...(ResourceId=item['Id']) print(f'fixed {item["Id"]}')
Pitfalls
The most common pitfall when fixing this on AWS App Runner is treating it as a one-off rather than as a recurring class of incident. The same misconfiguration tends to happen again after a deployment, a role rotation, or a region migration unless the fix is codified. Add a CloudFormation hook, Service Control Policy condition, or AWS Config rule that prevents the same misconfig from being introduced again. Documentation alone does not survive turnover.
Another common trap: confirming the fix on a single resource and assuming the fleet is healthy. Loop your check across every account, region, and IAM principal that could exhibit the same symptom. If you cannot enumerate the affected scope without a script, you do not yet understand the scope.
Full fix path
- Reproduce the original symptom path. If it still surfaces in any account or region or IAM role, you have not fixed it.
- Watch for 24 to 48 hours. AWS metrics and policy systems can mask issues with cached health for 6 to 12 hours, especially CloudFront and Route 53.
- Run a smoke test under realistic load. Happy-path tests miss race conditions and IAM session-cache issues.
- Capture the new state in a runbook so the next person on call does not have to rediscover this. Push it to Confluence or your team wiki, not into Slack.
- If the fix involved a permission change, run IAM Access Analyzer one more time to confirm you did not open a separate hole while closing this one.
Safety, rollback, blast radius
- Test in a non-production account if your environment has Control Tower or AWS Organizations. The cost of one sandbox account is cheaper than one rollback meeting.
- Export the existing config before changing it. Most AWS App Runner resources support describe + export to JSON via CLI - capture that to source control before you start.
- Know your rollback path. Some AWS App Runner operations are one-way (region migration, account-level feature opt-in, KMS key deletion past pending window). Confirm reversibility on the AWS doc before you commit.
- Be aware of cross-service impact. IAM role changes ripple to every service trusting that role. KMS key changes break every workload depending on that key. VPC endpoint changes affect every VPC consumer of that endpoint.
- Maintenance window discipline: if the change touches DNS, certificate rotation, or anything that emits TLS handshakes, line up a window with stakeholder notification, not a heroic mid-day swap.
FAQ
aws app describe-... first, then commit it before you change anything. A few operations are one-way (KMS key deletion past the pending window, region migration, account closure). Check the AWS doc for the specific API before you commit.aws CLI or SDK calls - those almost always still work.References
- docs.aws.amazon.com - official documentation for AWS App Runner
- AWS re:Post (formerly forums) - community Q&A with AWS-staff-verified answers
- AWS Health Dashboard at health.aws.amazon.com
- AWS Service Quotas console and AWS Well-Architected Tool
Related fixes
Related guides worth a look while you sort this one out:
- How to fix App Runner connection refused health check failures
- How to enable App Runner auto-deployment from GitHub on push
- How to fix App Runner build failed from GitHub source
- How to roll back an App Runner deployment quickly
- AppRunnerBuildFailed on App Runner. what causes it and how to fix
- AppRunnerDeploymentFailed on App Runner, what causes it and how to fix