{"record":{"id":"26f38482645d4bd2","repo":"kubernetes/kops","slug":"getting-aws-region-from-metadata-w","errorCode":null,"errorMessage":"getting AWS region from metadata: %w","messagePattern":"getting AWS region from metadata: %w","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"warning","filePath":"util/pkg/vfs/s3context.go","lineNumber":356,"sourceCode":"\tctx, span := tracer.Start(ctx, \"getRegionFromMetadata\")\n\tdefer span.End()\n\n\t// Use an even shorter timeout, to minimize impact when not running on EC2\n\t// Note that we still retry a few times, this works out a little under a 1s delay\n\tshortTimeout := &http.Client{\n\t\tTimeout: 100 * time.Millisecond,\n\t}\n\n\tconfig, err := awsconfig.LoadDefaultConfig(ctx, awsconfig.WithHTTPClient(shortTimeout))\n\tif err != nil {\n\t\treturn \"\", fmt.Errorf(\"failed to load AWS config: %w\", err)\n\t}\n\n\tclient := imds.NewFromConfig(config)\n\n\tmetadataRegion, err := client.GetRegion(ctx, &imds.GetRegionInput{})\n\tif err != nil {\n\t\treturn \"\", fmt.Errorf(\"getting AWS region from metadata: %w\", err)\n\t}\n\n\treturn metadataRegion.Region, nil\n}\n\nfunc VFSPath(url string) (string, error) {\n\tif !s3UrlRegexp.MatchString(url) {\n\t\treturn \"\", fmt.Errorf(\"%s is not a valid S3 URL\", url)\n\t}\n\tgroupNames := s3UrlRegexp.SubexpNames()\n\tresult := s3UrlRegexp.FindAllStringSubmatch(url, -1)[0]\n\n\tcaptured := map[string]string{}\n\tfor i, value := range result {\n\t\tif value != \"\" {\n\t\t\tcaptured[groupNames[i]] = value\n\t\t}\n\t}","sourceCodeStart":338,"sourceCodeEnd":374,"githubUrl":"https://github.com/kubernetes/kops/blob/4c8573c808a73d578c5eadc86d410646ea0b0d73/util/pkg/vfs/s3context.go#L338-L374","documentation":"After loading the AWS config, getRegionFromMetadata calls the IMDS client GetRegion to learn the region of the current EC2 instance. If that call fails (unreachable metadata service, timeout, missing token, IMDSv2 hop limit), the error is wrapped as this message. kOps uses this as a fallback to infer the region of the S3 state-store bucket.","triggerScenarios":"client.GetRegion(ctx, &imds.GetRegionInput{}) returns an error during getDetailsForBucket: the instance is tagged as EC2 (product_uuid starts with 'ec2') but IMDS is unreachable or slow — the HTTP client has only a 100ms timeout — IMDSv2 token request blocked (hop limit exceeded in containers, metadata option disabled on the instance), or IMDS endpoint firewalled by security group/network policy.","commonSituations":"Running kops inside a Docker/Kubernetes container on an EC2 host where the hop limit of 1 prevents IMDSv2 token acquisition; EC2 instance launched with instance metadata access disabled; host firewall or NetworkPolicy blocking 169.254.169.254; IMDS slow/overloaded so the 100ms timeout trips repeatedly (the code retries a few times, ~1s total).","solutions":["Increase the metadata response hop limit to 2 (EC2 console/CLI: modify-instance-metadata-options --http-put-response-hop-limit 2) when running in containers","Verify metadata access is enabled on the instance: aws ec2 describe-instances --query '...MetadataOptions'","Open access to 169.254.169.254 in firewall/security-group/NetworkPolicy and test: curl -m 1 http://169.254.169.254/latest/meta-data/placement/region","Avoid metadata inference entirely: set AWS_REGION in the environment so LoadDefaultConfig supplies the region without IMDS","On non-EC2 hosts misreporting EC2 product_uuid, correct the SMBIOS/product_uuid or run kops from outside that environment"],"exampleFix":"// before: container cannot get IMDSv2 token (hop limit 1)\n$ kops export kubecfg ...\nerror: getting AWS region from metadata: failed to get IMDSv2 token\n// after: raise hop limit on the instance\naws ec2 modify-instance-metadata-options --instance-id i-123 \\\n  --http-put-response-hop-limit 2 --http-endpoint enabled","handlingStrategy":"fallback","validationCode":"// Check IMDS reachability quickly before relying on it\ntimeout 2 curl -s http://169.254.169.254/latest/api/token -X PUT >/dev/null \\\n  || export AWS_REGION=us-east-1  # skip IMDS, use explicit region","typeGuard":"func isIMDSError(err error) bool {\n\treturn err != nil && strings.Contains(err.Error(), \"getting AWS region from metadata\")\n}","tryCatchPattern":"region, err := getRegionFromMetadata(ctx)\nif err != nil {\n\tif static := os.Getenv(\"AWS_REGION\"); static != \"\" {\n\t\tregion = static // fallback to explicit environment region\n\t} else {\n\t\treturn fmt.Errorf(\"could not infer AWS region: %w\", err)\n\t}\n}","preventionTips":["Set AWS_REGION in the environment so IMDS lookup is not needed","When running kops in containers on EC2, set metadata hop limit to 2 (--http-put-response-hop-limit 2)","Keep instance metadata enabled; verify with curl http://169.254.169.254/latest/meta-data/placement/region","Allow egress to 169.254.169.254 in host firewalls and Kubernetes NetworkPolicies","Prefer running kops off-cluster (laptop/CI) where IMDS inference isn't a dependency"],"tags":["aws","ec2-imds","network","timeout"],"backgroundTag":"ec2-metadata-unreachable","analyzedSha":"4c8573c808a73d578c5eadc86d410646ea0b0d73","analyzedAt":"2026-09-05T04:13:19.212Z","contentChangedAt":"2026-09-05T04:13:19.212Z","schemaVersion":2},"datasetVersion":"2026-09-12T07:17:12.445Z"}