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Add feature gate ExpandedDNSConfig

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ExpandedDNSConfig allows kubernetes to have expanded DNS(Domain Name
System) configuration
This commit is contained in:
Gunju Kim
2021-05-24 20:10:02 +09:00
parent 819059f641
commit 6317ce63c6
6 changed files with 296 additions and 45 deletions
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30
pkg/apis/core/validation/validation.go
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@@ -2961,10 +2961,14 @@ const (
// restrictions in Linux libc name resolution handling.
// Max number of DNS name servers.
MaxDNSNameservers = 3
// Max number of domains in search path.
MaxDNSSearchPaths = 6
// Max number of characters in search path.
MaxDNSSearchListChars = 256
// Expanded max number of domains in the search path list.
MaxDNSSearchPathsExpanded = 32
// Expanded max number of characters in the search path.
MaxDNSSearchListCharsExpanded = 2048
// Max number of domains in the search path list.
MaxDNSSearchPathsLegacy = 6
// Max number of characters in the search path list.
MaxDNSSearchListCharsLegacy = 256
)
func validateReadinessGates(readinessGates []core.PodReadinessGate, fldPath *field.Path) field.ErrorList {
@@ -2977,7 +2981,7 @@ func validateReadinessGates(readinessGates []core.PodReadinessGate, fldPath *fie
return allErrs
}
func validatePodDNSConfig(dnsConfig *core.PodDNSConfig, dnsPolicy *core.DNSPolicy, fldPath *field.Path) field.ErrorList {
func validatePodDNSConfig(dnsConfig *core.PodDNSConfig, dnsPolicy *core.DNSPolicy, fldPath *field.Path, opts PodValidationOptions) field.ErrorList {
allErrs := field.ErrorList{}
// Validate DNSNone case. Must provide at least one DNS name server.
@@ -3001,12 +3005,16 @@ func validatePodDNSConfig(dnsConfig *core.PodDNSConfig, dnsPolicy *core.DNSPolic
}
}
// Validate searches.
if len(dnsConfig.Searches) > MaxDNSSearchPaths {
allErrs = append(allErrs, field.Invalid(fldPath.Child("searches"), dnsConfig.Searches, fmt.Sprintf("must not have more than %v search paths", MaxDNSSearchPaths)))
maxDNSSearchPaths, maxDNSSearchListChars := MaxDNSSearchPathsLegacy, MaxDNSSearchListCharsLegacy
if opts.AllowExpandedDNSConfig {
maxDNSSearchPaths, maxDNSSearchListChars = MaxDNSSearchPathsExpanded, MaxDNSSearchListCharsExpanded
}
if len(dnsConfig.Searches) > maxDNSSearchPaths {
allErrs = append(allErrs, field.Invalid(fldPath.Child("searches"), dnsConfig.Searches, fmt.Sprintf("must not have more than %v search paths", maxDNSSearchPaths)))
}
// Include the space between search paths.
if len(strings.Join(dnsConfig.Searches, " ")) > MaxDNSSearchListChars {
allErrs = append(allErrs, field.Invalid(fldPath.Child("searches"), dnsConfig.Searches, "must not have more than 256 characters (including spaces) in the search list"))
if len(strings.Join(dnsConfig.Searches, " ")) > maxDNSSearchListChars {
allErrs = append(allErrs, field.Invalid(fldPath.Child("searches"), dnsConfig.Searches, fmt.Sprintf("must not have more than %v characters (including spaces) in the search list", maxDNSSearchListChars)))
}
for i, search := range dnsConfig.Searches {
// it is fine to have a trailing dot
@@ -3206,6 +3214,8 @@ type PodValidationOptions struct {
AllowIndivisibleHugePagesValues bool
// Allow hostProcess field to be set in windows security context
AllowWindowsHostProcessField bool
// Allow more DNSSearchPaths and longer DNSSearchListChars
AllowExpandedDNSConfig bool
}
// ValidatePodSingleHugePageResources checks if there are multiple huge
@@ -3326,7 +3336,7 @@ func ValidatePodSpec(spec *core.PodSpec, podMeta *metav1.ObjectMeta, fldPath *fi
allErrs = append(allErrs, ValidatePodSecurityContext(spec.SecurityContext, spec, fldPath, fldPath.Child("securityContext"))...)
allErrs = append(allErrs, validateImagePullSecrets(spec.ImagePullSecrets, fldPath.Child("imagePullSecrets"))...)
allErrs = append(allErrs, validateAffinity(spec.Affinity, fldPath.Child("affinity"))...)
allErrs = append(allErrs, validatePodDNSConfig(spec.DNSConfig, &spec.DNSPolicy, fldPath.Child("dnsConfig"))...)
allErrs = append(allErrs, validatePodDNSConfig(spec.DNSConfig, &spec.DNSPolicy, fldPath.Child("dnsConfig"), opts)...)
allErrs = append(allErrs, validateReadinessGates(spec.ReadinessGates, fldPath.Child("readinessGates"))...)
allErrs = append(allErrs, validateTopologySpreadConstraints(spec.TopologySpreadConstraints, fldPath.Child("topologySpreadConstraints"))...)
allErrs = append(allErrs, validateWindowsHostProcessPod(spec, fldPath, opts)...)