{"record":{"id":"a5bfd6a85bf47c4d","repo":"kubernetes/kops","slug":"error-starting-a-new-aws-session-v","errorCode":null,"errorMessage":"error starting a new AWS session: %v","messagePattern":"error starting a new AWS session: (.+?)","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"upup/pkg/fi/cloudup/awsup/aws_utils.go","lineNumber":64,"sourceCode":"func ValidateRegion(ctx context.Context, region string) error {\n\tallRegionsMutex.Lock()\n\tdefer allRegionsMutex.Unlock()\n\n\tif allRegions == nil {\n\t\tklog.V(2).Infof(\"Querying EC2 for all valid regions\")\n\n\t\trequest := &ec2.DescribeRegionsInput{}\n\t\tawsRegion := os.Getenv(\"AWS_REGION\")\n\t\tif awsRegion == \"\" {\n\t\t\tawsRegion = \"us-east-1\"\n\t\t}\n\t\tcfg, err := loadAWSConfig(ctx, awsRegion)\n\t\tif err != nil {\n\t\t\treturn fmt.Errorf(\"error loading AWS config: %v\", err)\n\t\t}\n\n\t\tif err != nil {\n\t\t\treturn fmt.Errorf(\"error starting a new AWS session: %v\", err)\n\t\t}\n\n\t\tclient := ec2.NewFromConfig(cfg)\n\n\t\tresponse, err := client.DescribeRegions(ctx, request)\n\t\tif err != nil {\n\t\t\treturn fmt.Errorf(\"got an error while querying for valid regions (verify your AWS credentials?): %v\", err)\n\t\t}\n\t\tallRegions = response.Regions\n\t}\n\n\tfor _, r := range allRegions {\n\t\tname := aws.ToString(r.RegionName)\n\t\tif name == region {\n\t\t\treturn nil\n\t\t}\n\t}\n","sourceCodeStart":46,"sourceCodeEnd":82,"githubUrl":"https://github.com/kubernetes/kops/blob/4c8573c808a73d578c5eadc86d410646ea0b0d73/upup/pkg/fi/cloudup/awsup/aws_utils.go#L46-L82","documentation":"After loading the SDK config, ValidateRegion creates an EC2 client; this error wraps a failure reported while establishing the AWS session/client setup for the region check. In practice it indicates the session could not be started with the given configuration — typically a credential or region resolution problem at session-creation time. It is a legacy-path message kept alongside the config-loading error in the same function.","triggerScenarios":"ValidateRegion (via BuildCloud or tests) reaching the session-creation branch when an underlying session/credential setup call returns a non-nil error for the chosen awsRegion.","commonSituations":"Credentials resolved but invalid/expired (SSO token stale), assume-role failures, or misconfigured region passed down so the SDK cannot build a valid client.","solutions":["Refresh credentials (aws sso login, re-run credential_process, or rotate keys)","Verify the region string is well-formed (e.g. us-east-1) before validation","Retry after fixing the AWS environment; check AWS_STS regional endpoints if assume-role is involved"],"exampleFix":"// before\nkops create cluster --region us-gov-west-1 ...  # with standard partition credentials\n// after\nkops create cluster --region us-east-1 ...       # region matching your credentials' partition","handlingStrategy":"retry","validationCode":"// ensure region is syntactically valid first\nfunc validRegionFormat(r string) bool {\n    re := regexp.MustCompile(`^[a-z]{2}(-gov)?-[a-z]+-\\d$`)\n    return re.MatchString(r)\n}","typeGuard":null,"tryCatchPattern":"err := kopsValidateRegion(ctx, region)\nif err != nil {\n    if isTransient(err) { // throttling/timeout\n        time.Sleep(backoff); err = kopsValidateRegion(ctx, region)\n    }\n    return err\n}","preventionTips":["Refresh SSO/assume-role tokens before long-running automation","Check clock skew (NTP) on CI runners since SigV4 fails on skewed clocks","Use the region matching your credentials' partition"],"tags":["aws","session","credentials","region"],"backgroundTag":"aws-session-start-failed","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"}