{"record":{"id":"a8258ade37200f7e","repo":"kubernetes/kops","slug":"generating-ecdsa-key-w","errorCode":null,"errorMessage":"generating ecdsa key: %w","messagePattern":"generating ecdsa key: %w","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"pkg/bootstrap/challenge.go","lineNumber":61,"sourceCode":"\t\tCommonName: \"kops-controller.\" + clusterName,\n\t}\n}\n\nfunc subjectsMatch(l, r pkix.Name) bool {\n\t// We need to check all the fields in challengeKopsControllerSubject\n\treturn l.CommonName == r.CommonName\n}\n\nfunc challengeServerHostName(clusterName string) string {\n\treturn \"challenge-server.\" + clusterName\n}\n\nfunc BuildChallengeServerCertificate(clusterName string) (*tls.Certificate, error) {\n\tserverName := challengeServerHostName(clusterName)\n\n\tprivateKey, err := pki.GeneratePrivateKey()\n\tif err != nil {\n\t\treturn nil, fmt.Errorf(\"generating ecdsa key: %w\", err)\n\t}\n\n\tkeyUsage := x509.KeyUsageDigitalSignature | x509.KeyUsageKeyEncipherment\n\n\tnow := time.Now()\n\tnotBefore := now.Add(-15 * time.Minute)\n\tnotAfter := notBefore.Add(time.Hour)\n\n\ttemplate := x509.Certificate{\n\t\tSerialNumber: big.NewInt(1),\n\t\tSubject: pkix.Name{\n\t\t\tCommonName: serverName,\n\t\t},\n\t\tNotBefore: notBefore,\n\t\tNotAfter:  notAfter,\n\n\t\tKeyUsage:              keyUsage,\n\t\tExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},","sourceCodeStart":43,"sourceCodeEnd":79,"githubUrl":"https://github.com/kubernetes/kops/blob/4c8573c808a73d578c5eadc86d410646ea0b0d73/pkg/bootstrap/challenge.go#L43-L79","documentation":"BuildChallengeServerCertificate wraps a failure from pki.GeneratePrivateKey while creating the ECDSA key for the challenge server's TLS certificate. This indicates the internal key generation failed, which is practically only caused by a failure of the underlying crypto/rand reader (system entropy unavailable).","triggerScenarios":"NewChallengeServer calls BuildChallengeServerCertificate on startup; pki.GeneratePrivateKey -> ecdsa.GenerateKey fails because crypto/rand cannot read from the OS entropy source.","commonSituations":"Container/host with exhausted or blocked /dev/urandom (seccomp policies, restricted devices); heavily constrained environments where getrandom(2) fails; custom crypto builds overriding the entropy source.","solutions":["Verify /dev/urandom is readable in the environment the server runs in (ls -l /dev/urandom; test with head -c 16 /dev/urandom)","Check seccomp/AppArmor or container security profiles that may block getrandom(2)","Restart the process — entropy failures are typically transient system-level problems","If it persists, inspect the Go build for any crypto/rand overrides or exotic platforms"],"exampleFix":null,"handlingStrategy":"retry","validationCode":null,"typeGuard":null,"tryCatchPattern":"cert, err := BuildChallengeServerCertificate(clusterName)\nif err != nil {\n  return fmt.Errorf(\"challenge server startup failed: %w\", err)\n}","preventionTips":["Ensure /dev/urandom is available and container security profiles allow getrandom(2)","Fail fast at startup so entropy problems surface immediately","Monitor host entropy health in constrained environments"],"tags":["crypto","tls","key-generation","entropy"],"backgroundTag":"key-generation-failed","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"}