{"record":{"id":"6c47a3e0437ee613","repo":"kubernetes/kops","slug":"error-writing-file-q-v","errorCode":null,"errorMessage":"error writing file %q: %v","messagePattern":"error writing file %q: (.+?)","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"pkg/dns/hosts/hosts.go","lineNumber":195,"sourceCode":"\t// Sort into a consistent order to minimize updates\n\tsort.Strings(block)\n\n\tout = append(out, GUARD_BEGIN)\n\tout = append(out, block...)\n\tout = append(out, GUARD_END)\n\tout = append(out, \"\")\n\n\tupdated := []byte(strings.Join(out, \"\\n\"))\n\n\tif bytes.Equal(updated, data) {\n\t\tklog.V(2).Infof(\"skipping update of unchanged /etc/hosts\")\n\t\treturn nil\n\t}\n\n\t// Note that because we are bind mounting /etc/hosts, we can't do a normal atomic file write\n\t// (where we write a temp file and rename it)\n\tif err := pseudoAtomicWrite(p, updated, stat.Mode()); err != nil {\n\t\treturn fmt.Errorf(\"error writing file %q: %v\", p, err)\n\t}\n\n\treturn nil\n}\n\n// Because we are bind-mounting /etc/hosts, we can't do a normal\n// atomic file write (where we write a temp file and rename it);\n// instead we write the file, pause, re-read and see if anyone else\n// wrote in the meantime; if so we rewrite again.  By pausing for a\n// random amount of time, eventually we'll win the write race and\n// exit.  This doesn't guarantee fairness, but it should mean that the\n// end-result is not malformed (i.e. partial writes).\nfunc pseudoAtomicWrite(p string, b []byte, mode os.FileMode) error {\n\tattempt := 0\n\tfor {\n\t\tattempt++\n\t\tif attempt > 10 {\n\t\t\treturn fmt.Errorf(\"failed to consistently write file %q - too many retries\", p)","sourceCodeStart":177,"sourceCodeEnd":213,"githubUrl":"https://github.com/kubernetes/kops/blob/4c8573c808a73d578c5eadc86d410646ea0b0d73/pkg/dns/hosts/hosts.go#L177-L213","documentation":"The pseudo-atomic rewrite of /etc/hosts (write, pause, re-read loop) ultimately failed; because /etc/hosts is bind-mounted, a rename-based atomic write is impossible and the in-place write itself errored (ENOSPC, EIO, or EACCES).","triggerScenarios":"Thrown at pkg/dns/hosts/hosts.go:195 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["Check disk space and write permissions on /etc/hosts","Verify the bind mount is writable (not mounted read-only)","Retry after resolving the underlying write error"],"exampleFix":null,"handlingStrategy":"retry","validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"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"}