{"record":{"id":"6c594c5b128894ca","repo":"kubernetes/kops","slug":"error-generating-random-label-suffix-w","errorCode":null,"errorMessage":"error generating random label suffix: %w","messagePattern":"error generating random label suffix: %w","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"upup/pkg/fi/cloudup/linodetasks/instance.go","lineNumber":321,"sourceCode":"\tvar interfaces []linodego.LinodeInterfaceCreateOptions\n\tif requirePublicInterface {\n\t\tinterfaces = append(interfaces, linodego.LinodeInterfaceCreateOptions{\n\t\t\tPublic: &linodego.PublicInterfaceCreateOptions{},\n\t\t})\n\t}\n\tinterfaces = append(interfaces, linodego.LinodeInterfaceCreateOptions{\n\t\tVPC: &linodego.VPCInterfaceCreateOptions{SubnetID: subnetID},\n\t})\n\n\treturn interfaces\n}\n\n// buildLinodeInstanceLabel generates a unique label for the Akamai (Linode) instance by appending a random suffix to the provided name.\n// It ensures that the final label does not exceed 64 characters and trims any trailing hyphens, underscores, or periods.\nfunc buildLinodeInstanceLabel(name string) (string, error) {\n\tvar randomSuffix [8]byte\n\tif _, err := cryptorand.Read(randomSuffix[:]); err != nil {\n\t\treturn \"\", fmt.Errorf(\"error generating random label suffix: %w\", err)\n\t}\n\n\tsuffix := fmt.Sprintf(\"-%x\", randomSuffix)\n\tmaxBaseLength := 64 - len(suffix)\n\tif len(name) > maxBaseLength {\n\t\tname = name[:maxBaseLength]\n\t}\n\tname = strings.TrimRight(name, \"-_.\")\n\n\treturn name + suffix, nil\n}\n\n// hasExpectedInterfaces checks if the Akamai (Linode) instance has the expected network interfaces.\n// It verifies that there is exactly one VPC interface with the matching subnet ID and checks for the presence of a public interface if required.\nfunc hasExpectedInterfaces(interfaces []linodego.LinodeInterface, subnetID int, requirePublicInterface bool) bool {\n\tpublicCount := 0\n\tvpcCount := 0\n\thasMatchingVPCSubnet := false","sourceCodeStart":303,"sourceCodeEnd":339,"githubUrl":"https://github.com/kubernetes/kops/blob/4c8573c808a73d578c5eadc86d410646ea0b0d73/upup/pkg/fi/cloudup/linodetasks/instance.go#L303-L339","documentation":"buildLinodeInstanceLabel appends a random hex suffix to the group name to create a unique Linode label. This wraps a failure reading random bytes from crypto/rand, without which no unique label can be produced.","triggerScenarios":"cryptorand.Read fails on the host (broken/limited entropy source) while generating the 8-byte suffix during instance creation.","commonSituations":"Running kops in a sandboxed container without /dev/urandom access, or a kernel with severely constrained entropy.","solutions":["Restore access to /dev/urandom on the host","Re-run kops update after fixing entropy","Move the operation to a host without entropy restrictions"],"exampleFix":null,"handlingStrategy":"try-catch","validationCode":null,"typeGuard":null,"tryCatchPattern":"label, err := buildLinodeInstanceLabel(name)\nif err != nil {\n    // check host entropy; abort or fall back to a deterministic suffix\n    return \"\", fmt.Errorf(\"error generating random label suffix: %w\", err)\n}","preventionTips":["Guarantee /dev/urandom access in CI containers","Keep group names short (<56 chars) — trimming doesn't avoid the random-read failure","Monitor for this only in sandboxed environments"],"tags":["linode","random","entropy"],"backgroundTag":"crypto-rand-failure","analyzedSha":"4c8573c808a73d578c5eadc86d410646ea0b0d73","analyzedAt":"2026-09-05T04:13:19.212Z","contentChangedAt":"2026-09-05T04:13:19.212Z","schemaVersion":2},"datasetVersion":"2026-09-12T12:17:11.808Z"}