kubeadm: Make it possible to configure volume mounts via the config file

cmd/kubeadm/app/apis/kubeadm/types.go

@@ -42,6 +42,10 @@ type MasterConfiguration struct {
 	ControllerManagerExtraArgs map[string]string
 	SchedulerExtraArgs         map[string]string
 
+	APIServerExtraVolumes         []HostPathMount
+	ControllerManagerExtraVolumes []HostPathMount
+	SchedulerExtraVolumes         []HostPathMount
+
 	// APIServerCertSANs sets extra Subject Alternative Names for the API Server signing cert
 	APIServerCertSANs []string
 	// CertificatesDir specifies where to store or look for all required certificates
@@ -137,3 +141,11 @@ func (cfg *MasterConfiguration) GetControlPlaneImageRepository() string {
 	}
 	return cfg.ImageRepository
 }
+
+// HostPathMount contains elements describing volumes that are mounted from the
+// host
+type HostPathMount struct {
+	Name      string
+	HostPath  string
+	MountPath string
+}

cmd/kubeadm/app/apis/kubeadm/v1alpha1/types.go

@@ -42,6 +42,10 @@ type MasterConfiguration struct {
 	ControllerManagerExtraArgs map[string]string `json:"controllerManagerExtraArgs,omitempty"`
 	SchedulerExtraArgs         map[string]string `json:"schedulerExtraArgs,omitempty"`
 
+	APIServerExtraVolumes         []HostPathMount `json:"apiServerExtraVolumes,omitempty"`
+	ControllerManagerExtraVolumes []HostPathMount `json:"controllerManagerExtraVolumes,omitempty"`
+	SchedulerExtraVolumes         []HostPathMount `json:"schedulerExtraVolumes,omitempty"`
+
 	// APIServerCertSANs sets extra Subject Alternative Names for the API Server signing cert
 	APIServerCertSANs []string `json:"apiServerCertSANs,omitempty"`
 	// CertificatesDir specifies where to store or look for all required certificates
@@ -119,3 +123,11 @@ type NodeConfiguration struct {
 	// the security of kubeadm since other nodes can impersonate the master.
 	DiscoveryTokenUnsafeSkipCAVerification bool `json:"discoveryTokenUnsafeSkipCAVerification"`
 }
+
+// HostPathMount contains elements describing volumes that are mounted from the
+// host
+type HostPathMount struct {
+	Name      string `json:"name"`
+	HostPath  string `json:"hostPath"`
+	MountPath string `json:"mountPath"`
+}

cmd/kubeadm/app/apis/kubeadm/v1alpha1/zz_generated.conversion.go

@@ -39,6 +39,8 @@ func RegisterConversions(scheme *runtime.Scheme) error {
 		Convert_kubeadm_API_To_v1alpha1_API,
 		Convert_v1alpha1_Etcd_To_kubeadm_Etcd,
 		Convert_kubeadm_Etcd_To_v1alpha1_Etcd,
+		Convert_v1alpha1_HostPathMount_To_kubeadm_HostPathMount,
+		Convert_kubeadm_HostPathMount_To_v1alpha1_HostPathMount,
 		Convert_v1alpha1_MasterConfiguration_To_kubeadm_MasterConfiguration,
 		Convert_kubeadm_MasterConfiguration_To_v1alpha1_MasterConfiguration,
 		Convert_v1alpha1_Networking_To_kubeadm_Networking,
@@ -104,6 +106,30 @@ func Convert_kubeadm_Etcd_To_v1alpha1_Etcd(in *kubeadm.Etcd, out *Etcd, s conver
 	return autoConvert_kubeadm_Etcd_To_v1alpha1_Etcd(in, out, s)
 }
 
+func autoConvert_v1alpha1_HostPathMount_To_kubeadm_HostPathMount(in *HostPathMount, out *kubeadm.HostPathMount, s conversion.Scope) error {
+	out.Name = in.Name
+	out.HostPath = in.HostPath
+	out.MountPath = in.MountPath
+	return nil
+}
+
+// Convert_v1alpha1_HostPathMount_To_kubeadm_HostPathMount is an autogenerated conversion function.
+func Convert_v1alpha1_HostPathMount_To_kubeadm_HostPathMount(in *HostPathMount, out *kubeadm.HostPathMount, s conversion.Scope) error {
+	return autoConvert_v1alpha1_HostPathMount_To_kubeadm_HostPathMount(in, out, s)
+}
+
+func autoConvert_kubeadm_HostPathMount_To_v1alpha1_HostPathMount(in *kubeadm.HostPathMount, out *HostPathMount, s conversion.Scope) error {
+	out.Name = in.Name
+	out.HostPath = in.HostPath
+	out.MountPath = in.MountPath
+	return nil
+}
+
+// Convert_kubeadm_HostPathMount_To_v1alpha1_HostPathMount is an autogenerated conversion function.
+func Convert_kubeadm_HostPathMount_To_v1alpha1_HostPathMount(in *kubeadm.HostPathMount, out *HostPathMount, s conversion.Scope) error {
+	return autoConvert_kubeadm_HostPathMount_To_v1alpha1_HostPathMount(in, out, s)
+}
+
 func autoConvert_v1alpha1_MasterConfiguration_To_kubeadm_MasterConfiguration(in *MasterConfiguration, out *kubeadm.MasterConfiguration, s conversion.Scope) error {
 	if err := Convert_v1alpha1_API_To_kubeadm_API(&in.API, &out.API, s); err != nil {
 		return err
@@ -123,6 +149,9 @@ func autoConvert_v1alpha1_MasterConfiguration_To_kubeadm_MasterConfiguration(in
 	out.APIServerExtraArgs = *(*map[string]string)(unsafe.Pointer(&in.APIServerExtraArgs))
 	out.ControllerManagerExtraArgs = *(*map[string]string)(unsafe.Pointer(&in.ControllerManagerExtraArgs))
 	out.SchedulerExtraArgs = *(*map[string]string)(unsafe.Pointer(&in.SchedulerExtraArgs))
+	out.APIServerExtraVolumes = *(*[]kubeadm.HostPathMount)(unsafe.Pointer(&in.APIServerExtraVolumes))
+	out.ControllerManagerExtraVolumes = *(*[]kubeadm.HostPathMount)(unsafe.Pointer(&in.ControllerManagerExtraVolumes))
+	out.SchedulerExtraVolumes = *(*[]kubeadm.HostPathMount)(unsafe.Pointer(&in.SchedulerExtraVolumes))
 	out.APIServerCertSANs = *(*[]string)(unsafe.Pointer(&in.APIServerCertSANs))
 	out.CertificatesDir = in.CertificatesDir
 	out.ImageRepository = in.ImageRepository
@@ -155,6 +184,9 @@ func autoConvert_kubeadm_MasterConfiguration_To_v1alpha1_MasterConfiguration(in
 	out.APIServerExtraArgs = *(*map[string]string)(unsafe.Pointer(&in.APIServerExtraArgs))
 	out.ControllerManagerExtraArgs = *(*map[string]string)(unsafe.Pointer(&in.ControllerManagerExtraArgs))
 	out.SchedulerExtraArgs = *(*map[string]string)(unsafe.Pointer(&in.SchedulerExtraArgs))
+	out.APIServerExtraVolumes = *(*[]HostPathMount)(unsafe.Pointer(&in.APIServerExtraVolumes))
+	out.ControllerManagerExtraVolumes = *(*[]HostPathMount)(unsafe.Pointer(&in.ControllerManagerExtraVolumes))
+	out.SchedulerExtraVolumes = *(*[]HostPathMount)(unsafe.Pointer(&in.SchedulerExtraVolumes))
 	out.APIServerCertSANs = *(*[]string)(unsafe.Pointer(&in.APIServerCertSANs))
 	out.CertificatesDir = in.CertificatesDir
 	out.ImageRepository = in.ImageRepository

cmd/kubeadm/app/apis/kubeadm/v1alpha1/zz_generated.deepcopy.go

@@ -39,6 +39,10 @@ func GetGeneratedDeepCopyFuncs() []conversion.GeneratedDeepCopyFunc {
 			in.(*Etcd).DeepCopyInto(out.(*Etcd))
 			return nil
 		}, InType: reflect.TypeOf(&Etcd{})},
+		{Fn: func(in interface{}, out interface{}, c *conversion.Cloner) error {
+			in.(*HostPathMount).DeepCopyInto(out.(*HostPathMount))
+			return nil
+		}, InType: reflect.TypeOf(&HostPathMount{})},
 		{Fn: func(in interface{}, out interface{}, c *conversion.Cloner) error {
 			in.(*MasterConfiguration).DeepCopyInto(out.(*MasterConfiguration))
 			return nil
@@ -102,6 +106,22 @@ func (in *Etcd) DeepCopy() *Etcd {
 	return out
 }
 
+// DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
+func (in *HostPathMount) DeepCopyInto(out *HostPathMount) {
+	*out = *in
+	return
+}
+
+// DeepCopy is an autogenerated deepcopy function, copying the receiver, creating a new HostPathMount.
+func (in *HostPathMount) DeepCopy() *HostPathMount {
+	if in == nil {
+		return nil
+	}
+	out := new(HostPathMount)
+	in.DeepCopyInto(out)
+	return out
+}
+
 // DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
 func (in *MasterConfiguration) DeepCopyInto(out *MasterConfiguration) {
 	*out = *in
@@ -136,6 +156,21 @@ func (in *MasterConfiguration) DeepCopyInto(out *MasterConfiguration) {
 			(*out)[key] = val
 		}
 	}
+	if in.APIServerExtraVolumes != nil {
+		in, out := &in.APIServerExtraVolumes, &out.APIServerExtraVolumes
+		*out = make([]HostPathMount, len(*in))
+		copy(*out, *in)
+	}
+	if in.ControllerManagerExtraVolumes != nil {
+		in, out := &in.ControllerManagerExtraVolumes, &out.ControllerManagerExtraVolumes
+		*out = make([]HostPathMount, len(*in))
+		copy(*out, *in)
+	}
+	if in.SchedulerExtraVolumes != nil {
+		in, out := &in.SchedulerExtraVolumes, &out.SchedulerExtraVolumes
+		*out = make([]HostPathMount, len(*in))
+		copy(*out, *in)
+	}
 	if in.APIServerCertSANs != nil {
 		in, out := &in.APIServerCertSANs, &out.APIServerCertSANs
 		*out = make([]string, len(*in))

cmd/kubeadm/app/apis/kubeadm/zz_generated.deepcopy.go

@@ -44,6 +44,10 @@ func RegisterDeepCopies(scheme *runtime.Scheme) error {
 			in.(*Etcd).DeepCopyInto(out.(*Etcd))
 			return nil
 		}, InType: reflect.TypeOf(&Etcd{})},
+		conversion.GeneratedDeepCopyFunc{Fn: func(in interface{}, out interface{}, c *conversion.Cloner) error {
+			in.(*HostPathMount).DeepCopyInto(out.(*HostPathMount))
+			return nil
+		}, InType: reflect.TypeOf(&HostPathMount{})},
 		conversion.GeneratedDeepCopyFunc{Fn: func(in interface{}, out interface{}, c *conversion.Cloner) error {
 			in.(*MasterConfiguration).DeepCopyInto(out.(*MasterConfiguration))
 			return nil
@@ -107,6 +111,22 @@ func (in *Etcd) DeepCopy() *Etcd {
 	return out
 }
 
+// DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
+func (in *HostPathMount) DeepCopyInto(out *HostPathMount) {
+	*out = *in
+	return
+}
+
+// DeepCopy is an autogenerated deepcopy function, copying the receiver, creating a new HostPathMount.
+func (in *HostPathMount) DeepCopy() *HostPathMount {
+	if in == nil {
+		return nil
+	}
+	out := new(HostPathMount)
+	in.DeepCopyInto(out)
+	return out
+}
+
 // DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
 func (in *MasterConfiguration) DeepCopyInto(out *MasterConfiguration) {
 	*out = *in
@@ -141,6 +161,21 @@ func (in *MasterConfiguration) DeepCopyInto(out *MasterConfiguration) {
 			(*out)[key] = val
 		}
 	}
+	if in.APIServerExtraVolumes != nil {
+		in, out := &in.APIServerExtraVolumes, &out.APIServerExtraVolumes
+		*out = make([]HostPathMount, len(*in))
+		copy(*out, *in)
+	}
+	if in.ControllerManagerExtraVolumes != nil {
+		in, out := &in.ControllerManagerExtraVolumes, &out.ControllerManagerExtraVolumes
+		*out = make([]HostPathMount, len(*in))
+		copy(*out, *in)
+	}
+	if in.SchedulerExtraVolumes != nil {
+		in, out := &in.SchedulerExtraVolumes, &out.SchedulerExtraVolumes
+		*out = make([]HostPathMount, len(*in))
+		copy(*out, *in)
+	}
 	if in.APIServerCertSANs != nil {
 		in, out := &in.APIServerCertSANs, &out.APIServerCertSANs
 		*out = make([]string, len(*in))

cmd/kubeadm/app/phases/controlplane/manifests.go

@@ -77,7 +77,7 @@ func GetStaticPodSpecs(cfg *kubeadmapi.MasterConfiguration, k8sVersion *version.
 			Name:          kubeadmconstants.KubeAPIServer,
 			Image:         images.GetCoreImage(kubeadmconstants.KubeAPIServer, cfg.GetControlPlaneImageRepository(), cfg.KubernetesVersion, cfg.UnifiedControlPlaneImage),
 			Command:       getAPIServerCommand(cfg, k8sVersion),
-			VolumeMounts:  mounts.GetVolumeMounts(kubeadmconstants.KubeAPIServer),
+			VolumeMounts:  staticpodutil.VolumeMountMapToSlice(mounts.GetVolumeMounts(kubeadmconstants.KubeAPIServer)),
 			LivenessProbe: staticpodutil.ComponentProbe(int(cfg.API.BindPort), "/healthz", v1.URISchemeHTTPS),
 			Resources:     staticpodutil.ComponentResources("250m"),
 			Env:           getProxyEnvVars(),
@@ -86,7 +86,7 @@ func GetStaticPodSpecs(cfg *kubeadmapi.MasterConfiguration, k8sVersion *version.
 			Name:          kubeadmconstants.KubeControllerManager,
 			Image:         images.GetCoreImage(kubeadmconstants.KubeControllerManager, cfg.GetControlPlaneImageRepository(), cfg.KubernetesVersion, cfg.UnifiedControlPlaneImage),
 			Command:       getControllerManagerCommand(cfg, k8sVersion),
-			VolumeMounts:  mounts.GetVolumeMounts(kubeadmconstants.KubeControllerManager),
+			VolumeMounts:  staticpodutil.VolumeMountMapToSlice(mounts.GetVolumeMounts(kubeadmconstants.KubeControllerManager)),
 			LivenessProbe: staticpodutil.ComponentProbe(10252, "/healthz", v1.URISchemeHTTP),
 			Resources:     staticpodutil.ComponentResources("200m"),
 			Env:           getProxyEnvVars(),
@@ -95,7 +95,7 @@ func GetStaticPodSpecs(cfg *kubeadmapi.MasterConfiguration, k8sVersion *version.
 			Name:          kubeadmconstants.KubeScheduler,
 			Image:         images.GetCoreImage(kubeadmconstants.KubeScheduler, cfg.GetControlPlaneImageRepository(), cfg.KubernetesVersion, cfg.UnifiedControlPlaneImage),
 			Command:       getSchedulerCommand(cfg),
-			VolumeMounts:  mounts.GetVolumeMounts(kubeadmconstants.KubeScheduler),
+			VolumeMounts:  staticpodutil.VolumeMountMapToSlice(mounts.GetVolumeMounts(kubeadmconstants.KubeScheduler)),
 			LivenessProbe: staticpodutil.ComponentProbe(10251, "/healthz", v1.URISchemeHTTP),
 			Resources:     staticpodutil.ComponentResources("100m"),
 			Env:           getProxyEnvVars(),

cmd/kubeadm/app/phases/controlplane/volumes.go

@@ -86,40 +86,85 @@ func getHostPathVolumesForTheControlPlane(cfg *kubeadmapi.MasterConfiguration) c
 		mounts.NewHostPathMount(kubeadmconstants.KubeControllerManager, caCertsPkiVolumeName, caCertsPkiVolumePath, caCertsPkiVolumePath, true, &hostPathDirectoryOrCreate)
 	}
 
+	// Merge user defined mounts and ensure unique volume and volume mount
+	// names
+	mounts.AddExtraHostPathMounts(kubeadmconstants.KubeAPIServer, cfg.APIServerExtraVolumes, true, &hostPathDirectoryOrCreate)
+	mounts.AddExtraHostPathMounts(kubeadmconstants.KubeControllerManager, cfg.ControllerManagerExtraVolumes, true, &hostPathDirectoryOrCreate)
+	mounts.AddExtraHostPathMounts(kubeadmconstants.KubeScheduler, cfg.SchedulerExtraVolumes, true, &hostPathDirectoryOrCreate)
+
 	return mounts
 }
 
 // controlPlaneHostPathMounts is a helper struct for handling all the control plane's hostPath mounts in an easy way
 type controlPlaneHostPathMounts struct {
-	volumes      map[string][]v1.Volume
-	volumeMounts map[string][]v1.VolumeMount
+	// volumes is a nested map that forces a unique volumes. The outer map's
+	// keys are a string that should specify the target component to add the
+	// volume to. The values (inner map) of the outer map are maps with string
+	// keys and v1.Volume values. The inner map's key should specify the volume
+	// name.
+	volumes map[string]map[string]v1.Volume
+	// volumeMounts is a nested map that forces a unique volume mounts. The
+	// outer map's keys are a string that should specify the target component
+	// to add the volume mount to. The values (inner map) of the outer map are
+	// maps with string keys and v1.VolumeMount values. The inner map's key
+	// should specify the volume mount name.
+	volumeMounts map[string]map[string]v1.VolumeMount
 }
 
 func newControlPlaneHostPathMounts() controlPlaneHostPathMounts {
 	return controlPlaneHostPathMounts{
-		volumes:      map[string][]v1.Volume{},
-		volumeMounts: map[string][]v1.VolumeMount{},
+		volumes:      map[string]map[string]v1.Volume{},
+		volumeMounts: map[string]map[string]v1.VolumeMount{},
 	}
 }
 
 func (c *controlPlaneHostPathMounts) NewHostPathMount(component, mountName, hostPath, containerPath string, readOnly bool, hostPathType *v1.HostPathType) {
-	c.volumes[component] = append(c.volumes[component], staticpodutil.NewVolume(mountName, hostPath, hostPathType))
-	c.volumeMounts[component] = append(c.volumeMounts[component], staticpodutil.NewVolumeMount(mountName, containerPath, readOnly))
+	vol := staticpodutil.NewVolume(mountName, hostPath, hostPathType)
+	c.addComponentVolume(component, vol)
+	volMount := staticpodutil.NewVolumeMount(mountName, containerPath, readOnly)
+	c.addComponentVolumeMount(component, volMount)
 }
 
 func (c *controlPlaneHostPathMounts) AddHostPathMounts(component string, vols []v1.Volume, volMounts []v1.VolumeMount) {
-	c.volumes[component] = append(c.volumes[component], vols...)
-	c.volumeMounts[component] = append(c.volumeMounts[component], volMounts...)
+	for _, v := range vols {
+		c.addComponentVolume(component, v)
+	}
+	for _, v := range volMounts {
+		c.addComponentVolumeMount(component, v)
+	}
+}
+
+// AddExtraHostPathMounts adds host path mounts and overwrites the default
+// paths in the case that a user specifies the same volume/volume mount name.
+func (c *controlPlaneHostPathMounts) AddExtraHostPathMounts(component string, extraVols []kubeadmapi.HostPathMount, readOnly bool, hostPathType *v1.HostPathType) {
+	for _, extraVol := range extraVols {
+		fmt.Printf("[controlplane] Adding extra host path mount %q to %q\n", extraVol.Name, component)
+		c.NewHostPathMount(component, extraVol.Name, extraVol.HostPath, extraVol.MountPath, readOnly, hostPathType)
+	}
 }
 
-func (c *controlPlaneHostPathMounts) GetVolumes(component string) []v1.Volume {
+func (c *controlPlaneHostPathMounts) GetVolumes(component string) map[string]v1.Volume {
 	return c.volumes[component]
 }
 
-func (c *controlPlaneHostPathMounts) GetVolumeMounts(component string) []v1.VolumeMount {
+func (c *controlPlaneHostPathMounts) GetVolumeMounts(component string) map[string]v1.VolumeMount {
 	return c.volumeMounts[component]
 }
 
+func (c *controlPlaneHostPathMounts) addComponentVolume(component string, vol v1.Volume) {
+	if _, ok := c.volumes[component]; !ok {
+		c.volumes[component] = map[string]v1.Volume{}
+	}
+	c.volumes[component][vol.Name] = vol
+}
+
+func (c *controlPlaneHostPathMounts) addComponentVolumeMount(component string, volMount v1.VolumeMount) {
+	if _, ok := c.volumeMounts[component]; !ok {
+		c.volumeMounts[component] = map[string]v1.VolumeMount{}
+	}
+	c.volumeMounts[component][volMount.Name] = volMount
+}
+
 // getEtcdCertVolumes returns the volumes/volumemounts needed for talking to an external etcd cluster
 func getEtcdCertVolumes(etcdCfg kubeadmapi.Etcd) ([]v1.Volume, []v1.VolumeMount) {
 	certPaths := []string{etcdCfg.CAFile, etcdCfg.CertFile, etcdCfg.KeyFile}