CONTAINER_FAILED_TO_START on Cloud Run. what causes it and how to fix

By Sai Kiran Pandrala · Last verified: 2026-05-31 · Source: community Q&A, Google Cloud Community, Google Cloud docs

Engineers running Cloud Run hit CONTAINER_FAILED_TO_START on Cloud Run, what causes it and how to fix often enough that there is a stable fix pattern. This page captures it in the order Google Cloud support would run it during a real incident.

What container_failed_to_start on cloud run, what causes it and how to fix actually involves on Cloud Run

The CONTAINER_FAILED_TO_START error from AWS typically surfaces with the message "The user-provided container failed to start and listen on the port defined by the PORT=8080 environment variable". The error code itself is what you grep for in AWS re:Post or in AWS Support cases, not the human-readable line.

On Cloud Run, this most often comes from one of three causes: a missing or restrictive IAM permission, a service-level limit you have hit, or a transient AWS-side capacity issue. The fix path differs by which.

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.

Diagnose first, fix second

Pull the Google Cloud request ID from the response headers: x-goog-request-id from response headers (or the insertId field in Cloud Logging for asynchronous calls). Google Cloud Support needs these IDs to look up your call in their internal logs - without them, the first reply on a ticket will ask you to reproduce the call and capture them. Save them with a timestamp; Google Cloud Support cannot retrieve calls older than 90 days for most services.

Start by capturing the exact Google Cloud error string. The Cloud Console truncates messages in popups, but Cloud Logging keeps the full record in protoPayload.status and protoPayload.methodName. The camelCase error code (e.g. AccessDenied, InsufficientInstanceCapacity, ConditionalCheckFailedException) is the thing you grep for in Google Cloud Community 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 Google-staff-verified answer within the first three results.

Look at the Cloud Audit Log event for the failed call, even if you are not enrolled in Cloud Logging Log Router. The basic 90-day event history works for most diagnostic purposes and lives in the console under Cloud Audit Logs > Event history. Filter by event name (the API action) and time range; the event JSON shows the exact user identity, source IP, request parameters, and error code.

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 you cannot reproduce the failure consistently, the cause is probably a race condition or a session-cache issue. Run the call with --profile set to a fresh STS session, in a different region you control, with a single concurrent request. If it works there but fails in your normal setup, the difference is the bug.

Most Cloud Run failures fall into one of three buckets: IAM permission gap, networking path break (security group, NACL, or VPC endpoint policy), or service-limit / quota hit. Run that mental triage first - it covers around 80 percent of real-world cases. If the failure does not fit any of the three, it is likely a service-side regression worth opening a re:Post or support ticket for.

Automate this fix so you do not do it twice

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('cloud', 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"]}')

Codify the fix in Terraform or Deployment Manager

When you reach for the console to fix the same issue twice, the third occurrence should be solved in IaC, not in the console. Terraform's terraform import and Deployment Manager or Terraform's resource importer let you adopt the existing resource into state without recreating it. Lock the corrected attribute behind a variable so the next operator does not have to rediscover the value. Add a moved {} block or Deployment Manager or Terraform resource refactor to keep the diff clean.

Add a Workflows or Cloud Tasks Automation runbook

For multi-step fixes that include a manual approval, use Workflows runbook. Document the fix as a runbook with workflows.executions.approve steps where a human signs off and workflows.steps.callApi steps where the runbook calls the Google Cloud API. Approvers are notified by SNS; the runbook execution shows up in Cloud Audit Logs with the approver's identity attached. This makes audit trails easy and stops production fixes from being one-person operations.

Common pitfalls and what to watch for

A subtle pitfall on Cloud Run is that the Cloud Console and the SDK can disagree about resource state during a configuration change. Console UI is cached for performance and may show the old config for up to 10 minutes after you change it via API or Deployment Manager or Terraform. Always confirm with describe-* CLI calls during a change window, not with screenshots from the Console.

The other pitfall: assuming that an automated remediation is correct because it succeeded. A Lambda that fires on a Cloud Monitoring alert policy and runs a remediation step should also publish a metric for every remediation; sudden surges in auto-fix invocations are themselves an outage signal. Otherwise you can hide a slow-burn regression behind a quiet remediation loop for weeks.

Verify the fix worked

• Reproduce the original symptom path. If it still surfaces in any account or region or IAM role or service account, you have not fixed it.
• Watch for 24 to 48 hours. Cloud Monitoring metrics and Cloud Asset Inventory can mask issues with cached health for 6 to 12 hours, especially Cloud CDN and Cloud DNS.
• 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 Resource Manager and Organization Policy or Cloud Resource Manager (organizations, folders, projects). The cost of one sandbox account is cheaper than one rollback meeting.
• Export the existing config before changing it. Most Cloud Run resources support describe + export to JSON via CLI - capture that to source control before you start.
• Know your rollback path. Some Cloud Run operations are one-way (region migration, account-level feature opt-in, Cloud KMS key deletion past pending window). Confirm reversibility on the Google Cloud doc before you commit.
• Be aware of cross-service impact. IAM role or service account changes ripple to every service trusting that role. Cloud 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

Related fixes

Related guides worth a look while you sort this one out:

• CONTAINER_HEALTHCHECK_FAILED on Cloud Run: what causes it and how to fix
• RUNNABLE_CONTAINER_PULL_FAILED on Cloud Batch, what causes it and how to fix
• CONTAINER_HEALTHY_INSPECTION_FAILED on Cloud Functions: what causes it and how to fix
• CONTAINER_EXITED_EARLY on Cloud Run, what causes it and how to fix
• CONTAINER_SIGKILL on Cloud Run, what causes it and how to fix
• How to fix Container failed to start and listen on PORT=8080 on Cloud Run