expose master count configuration in a cli option on apiserver

cmd/kube-apiserver/app/server.go

@@ -106,6 +106,7 @@ type APIServer struct {
 	ServiceNodePortRange       util.PortRange
 	EnableLogsSupport          bool
 	MasterServiceNamespace     string
+	MasterCount                int
 	RuntimeConfig              util.ConfigurationMap
 	KubeletConfig              kubeletclient.KubeletClientConfig
 	EnableProfiling            bool
@@ -134,6 +135,7 @@ func NewAPIServer() *APIServer {
 		EtcdPathPrefix:         genericapiserver.DefaultEtcdPathPrefix,
 		EnableLogsSupport:      true,
 		MasterServiceNamespace: api.NamespaceDefault,
+		MasterCount:            1,
 		CertDirectory:          "/var/run/kubernetes",
 		StorageVersions:        latest.AllPreferredGroupVersions(),
 
@@ -241,6 +243,7 @@ func (s *APIServer) AddFlags(fs *pflag.FlagSet) {
 	fs.Var(&s.ServiceNodePortRange, "service-node-ports", "Deprecated: see --service-node-port-range instead.")
 	fs.MarkDeprecated("service-node-ports", "see --service-node-port-range instead.")
 	fs.StringVar(&s.MasterServiceNamespace, "master-service-namespace", s.MasterServiceNamespace, "The namespace from which the kubernetes master services should be injected into pods")
+	fs.IntVar(&s.MasterCount, "apiserver-count", s.MasterCount, "The number of apiservers running in the cluster")
 	fs.Var(&s.RuntimeConfig, "runtime-config", "A set of key=value pairs that describe runtime configuration that may be passed to apiserver. apis/<groupVersion> key can be used to turn on/off specific api versions. apis/<groupVersion>/<resource> can be used to turn on/off specific resources. api/all and api/legacy are special keys to control all and legacy api versions respectively.")
 	fs.BoolVar(&s.EnableProfiling, "profiling", true, "Enable profiling via web interface host:port/debug/pprof/")
 	// TODO: enable cache in integration tests.
@@ -561,6 +564,7 @@ func (s *APIServer) Run(_ []string) error {
 			AdmissionControl:          admissionController,
 			APIGroupVersionOverrides:  apiGroupVersionOverrides,
 			MasterServiceNamespace:    s.MasterServiceNamespace,
+			MasterCount:               s.MasterCount,
 			ExternalHost:              s.ExternalHost,
 			MinRequestTimeout:         s.MinRequestTimeout,
 			ProxyDialer:               proxyDialerFn,

docs/admin/kube-apiserver.md

@@ -54,6 +54,7 @@ kube-apiserver
       --admission-control-config-file="": File with admission control configuration.
       --advertise-address=<nil>: The IP address on which to advertise the apiserver to members of the cluster. This address must be reachable by the rest of the cluster. If blank, the --bind-address will be used. If --bind-address is unspecified, the host's default interface will be used.
       --allow-privileged[=false]: If true, allow privileged containers.
+      --apiserver-count=1: The number of apiservers running in the cluster
       --authorization-mode="AlwaysAllow": Ordered list of plug-ins to do authorization on secure port. Comma-delimited list of: AlwaysAllow,AlwaysDeny,ABAC
       --authorization-policy-file="": File with authorization policy in csv format, used with --authorization-mode=ABAC, on the secure port.
       --basic-auth-file="": If set, the file that will be used to admit requests to the secure port of the API server via http basic authentication.
@@ -105,7 +106,7 @@ kube-apiserver
       --watch-cache[=true]: Enable watch caching in the apiserver
 ```
 
-###### Auto generated by spf13/cobra on 15-Dec-2015
+###### Auto generated by spf13/cobra on 18-Dec-2015
 
 
 <!-- BEGIN MUNGE: GENERATED_ANALYTICS -->

hack/verify-flags/known-flags.txt

@@ -9,6 +9,7 @@ algorithm-provider
 all-namespaces
 allocate-node-cidrs
 allow-privileged
+apiserver-count
 api-server-address
 api-burst
 api-prefix