Known issues in Cloud Run

This page lists known issues, limitations, and unsupported features in Cloud Run.

You can also check for existing issues or open new issues in the public issue trackers.

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Category Issue and workaround
Deployment

Cloud Run job tasks might be spuriously marked as retried

In some situations, a task can be marked as retried, even when the task succeeded on its first try. Until this issue is resolved, Google recommends keeping the --max-retries parameter set to 3 or higher to avoid spurious execution failures.

Deployment

Volume Mounts are incompatible with Config Connector

If you deploy your Cloud Run service or job with Config Connector, your volume mounts won't be persisted next time you deploy. You may also experience issues using Config Connector with services or jobs that have volume mounts already applied.

Serving

HOME environment variable is set to /home in first generation execution environment

Cloud Run first generation execution environment sets the HOME environment variable to /home. The second generation execution environment sets the HOME variable to the value in /etc/passwd for the running user, or falls back to /home if the /etc/passwd doesn't exist, or if the user can't be found in /etc/passwd.

Serving

You can't mount secrets on /tmp in first generation execution environment

If you use first generation execution environment, you can't mount secrets on /tmp directly. However, you can mount secrets on any subdirectory of /tmp.

Serving

High request latency with custom domains when invoking from some regions

Requests to Cloud Run services using custom domains might have a very high latency from some locations. This issue is more pronounced for Cloud Run services in asia-northeast1 and us-east4. If you observe this issue, you can achieve greater performance with Cloud Load Balancing using a serverless NEG.

Serving

Sometimes a request might be sent to instances before startup probe results are known

Cloud Run might use the request sent to the service endpoint to start an instance. Before the startup probe results are known, Cloud Run might also assign the request to the instance. If the probe passes, then the instance will process the request at the receiveTimestamp listed in the Cloud Run request log. If the probe fails, then Cloud Run logs failure without entering the service's code.

Connectivity and security

Custom domain mappings require enabled run.app URLs

You can only map custom domains for Cloud Run services that have a default run.app URL. Until this issue is resolved, if you've disabled the default run.app URL, we recommend that you enable the default run.app URL, map the custom domain, and then disable the default run.app URL again.

Connectivity and security

Serverless VPC Access doesn't support IPv6

You can't use IPv6 when sending traffic through Serverless VPC Access connectors. IPv6 is supported when Direct VPC egress uses dual-stack subnets or when accessing non-VPC endpoints while vpc-egress is set to private-ranges-only.

Connectivity and security

IP addresses not clearly identified when in use by serverless

When you use Direct VPC egress, you can identify IP addresses reserved by Cloud Run that are currently in use, displayed as None instead of Serverless on the IP addresses page in the Google Cloud console.

URL

Reserved URL paths

You can't use the following URL paths:
  • /eventlog
  • Paths starting with /_ah/
  • Some paths ending with z. To prevent conflicts with reserved paths, we recommend avoiding all paths that end in z
URL

Some encoded URL characters are decoded

Cloud Run decodes some encoded characters in the Cloud Run services URL before reaching the container instance. For example, %41 is automatically decoded to A.

Unsupported services and features

Unsupported services

Web Security Scanner
Unsupported services and features

HTTP/2 Push

Cloud Run supports HTTP/2, but not HTTP/2 Server Push.

Unsupported services and features

HTTP methods

Cloud Run doesn't support requests with HTTP methods like TRACE and CONNECT. As a result, these methods aren't received by services running on Cloud Run.

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