Add --extra-disks capability to kvm2 driver

cmd/minikube/cmd/start_flags.go

@@ -168,7 +168,7 @@ func initMinikubeFlags() {
 	startCmd.Flags().StringP(network, "", "", "network to run minikube with. Now it is used by docker/podman and KVM drivers. If left empty, minikube will create a new network.")
 	startCmd.Flags().StringVarP(&outputFormat, "output", "o", "text", "Format to print stdout in. Options include: [text,json]")
 	startCmd.Flags().StringP(trace, "", "", "Send trace events. Options include: [gcp]")
-	startCmd.Flags().Int(extraDisks, 0, "Number of extra disks created and attached to the minikube VM (currently only implemented for hyperkit driver)")
+	startCmd.Flags().Int(extraDisks, 0, "Number of extra disks created and attached to the minikube VM (currently only implemented for hyperkit and kvm2 drivers)")
 }
 
 // initKubernetesFlags inits the commandline flags for Kubernetes related options
@@ -730,7 +730,7 @@ func interpretWaitFlag(cmd cobra.Command) map[string]bool {
 }
 
 func checkExtraDiskOptions(cmd *cobra.Command, driverName string) {
-	supportedDrivers := []string{driver.HyperKit}
+	supportedDrivers := []string{driver.HyperKit, driver.KVM2}
 
 	if cmd.Flags().Changed(extraDisks) {
 		supported := false

pkg/drivers/kvm/disks.go

@@ -0,0 +1,80 @@
+// +build linux
+
+/*
+Copyright 2018 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package kvm
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"text/template"
+
+	"github.com/docker/machine/libmachine/log"
+	"github.com/pkg/errors"
+	"k8s.io/minikube/pkg/drivers"
+	"k8s.io/minikube/pkg/util"
+)
+
+// extraDisksTmpl ExtraDisks XML Template
+const extraDisksTmpl = `
+<disk type='file' device='disk'>
+  <driver name='qemu' type='raw' cache='default' io='threads' />
+  <source file='{{.DiskPath}}'/>
+  <target dev='{{.DiskLogicalName}}' bus='virtio'/>
+</disk>
+`
+
+// ExtraDisks holds the extra disks configuration
+type ExtraDisks struct {
+	DiskPath        string
+	DiskLogicalName string
+}
+
+// getExtraDiskXML returns the XML that can be added to the libvirt domain XML
+// for additional disks
+func getExtraDiskXML(diskpath string, logicalName string) (string, error) {
+	var extraDisk ExtraDisks
+	extraDisk.DiskLogicalName = logicalName
+	extraDisk.DiskPath = diskpath
+	tmpl := template.Must(template.New("").Parse(extraDisksTmpl))
+	var extraDisksXML bytes.Buffer
+	if err := tmpl.Execute(&extraDisksXML, extraDisk); err != nil {
+		return "", fmt.Errorf("couldn't generate extra disks XML: %v", err)
+	}
+	return extraDisksXML.String(), nil
+}
+
+// createExtraDisks creates the extra disk files
+func createExtraDisk(d *Driver, index int) (string, error) {
+	diskPath := drivers.ExtraDiskPath(d.BaseDriver, index)
+	log.Infof("Creating raw disk image: %s of size %v", diskPath, d.DiskSize)
+
+	if _, err := os.Stat(diskPath); os.IsNotExist(err) {
+		file, err := os.OpenFile(diskPath, os.O_CREATE|os.O_EXCL|os.O_WRONLY, 0644)
+		if err != nil {
+			return "", errors.Wrap(err, "open")
+		}
+		defer file.Close()
+
+		if err := file.Truncate(util.ConvertMBToBytes(d.DiskSize)); err != nil {
+			return "", errors.Wrap(err, "truncate")
+		}
+	}
+	return diskPath, nil
+
+}

pkg/drivers/kvm/domain_definition_arm64.go

@@ -77,6 +77,9 @@ const domainTmpl = `
     {{if .GPU}}
     {{.DevicesXML}}
     {{end}}
+    {{if gt .ExtraDisks 0}}
+    {{.ExtraDisksXML}}
+    {{end}}
   </devices>
 </domain>
 `

pkg/drivers/kvm/domain_definition_x86.go

@@ -75,6 +75,9 @@ const domainTmpl = `
     {{if .GPU}}
     {{.DevicesXML}}
     {{end}}
+    {{if gt .ExtraDisks 0}}
+    {{.ExtraDisksXML}}
+    {{end}}
   </devices>
 </domain>
 `

pkg/drivers/kvm/kvm.go

@@ -88,6 +88,12 @@ type Driver struct {
 
 	// NUMA XML
 	NUMANodeXML string
+
+	// Extra Disks
+	ExtraDisks int
+
+	// Extra Disks XML
+	ExtraDisksXML []string
 }
 
 const (
@@ -352,6 +358,26 @@ func (d *Driver) Create() (err error) {
 		return errors.Wrap(err, "error creating disk")
 	}
 
+	if d.ExtraDisks > 20 {
+		// Limiting the number of disks to 20 arbitrarily. If more disks are
+		// needed, the logical name generation has to changed to create them if
+		// the form hdaa, hdab, etc
+		return errors.Wrap(err, "cannot create more than 20 extra disks")
+	}
+	for i := 0; i < d.ExtraDisks; i++ {
+		diskpath, err := createExtraDisk(d, i)
+		if err != nil {
+			return errors.Wrap(err, "creating extra disks")
+		}
+		// Starting the logical names for the extra disks from hdd as the cdrom device is set to hdc.
+		// TODO: Enhance the domain template to use variable for the logical name of the main disk and the cdrom disk.
+		extraDisksXML, err := getExtraDiskXML(diskpath, fmt.Sprintf("hd%v", string(rune('d'+i))))
+		if err != nil {
+			return errors.Wrap(err, "creating extraDisk XML")
+		}
+		d.ExtraDisksXML = append(d.ExtraDisksXML, extraDisksXML)
+	}
+
 	if err := ensureDirPermissions(store); err != nil {
 		log.Errorf("unable to ensure permissions on %s: %v", store, err)
 	}

pkg/minikube/config/types.go

@@ -83,7 +83,7 @@ type ClusterConfig struct {
 	ListenAddress           string   // Only used by the docker and podman driver
 	Network                 string   // only used by docker driver
 	MultiNodeRequested      bool
-	ExtraDisks              int // currently only implemented for hyperkit
+	ExtraDisks              int // currently only implemented for hyperkit and kvm2
 }
 
 // KubernetesConfig contains the parameters used to configure the VM Kubernetes.

pkg/minikube/registry/drvs/kvm2/kvm2.go

@@ -70,6 +70,7 @@ type kvmDriver struct {
 	Hidden         bool
 	ConnectionURI  string
 	NUMANodeCount  int
+	ExtraDisks     int
 }
 
 func configure(cc config.ClusterConfig, n config.Node) (interface{}, error) {
@@ -92,6 +93,7 @@ func configure(cc config.ClusterConfig, n config.Node) (interface{}, error) {
 		Hidden:         cc.KVMHidden,
 		ConnectionURI:  cc.KVMQemuURI,
 		NUMANodeCount:  cc.KVMNUMACount,
+		ExtraDisks:     cc.ExtraDisks,
 	}, nil
 }
 

site/content/en/docs/commands/start.md

@@ -48,7 +48,7 @@ minikube start [flags]
                                           		The key should be '.' separated, and the first part before the dot is the component to apply the configuration to.
                                           		Valid components are: kubelet, kubeadm, apiserver, controller-manager, etcd, proxy, scheduler
                                           		Valid kubeadm parameters: ignore-preflight-errors, dry-run, kubeconfig, kubeconfig-dir, node-name, cri-socket, experimental-upload-certs, certificate-key, rootfs, skip-phases, pod-network-cidr
-      --extra-disks int                   Number of extra disks created and attached to the minikube VM (currently only implemented for hyperkit driver)
+      --extra-disks int                   Number of extra disks created and attached to the minikube VM (currently only implemented for hyperkit and kvm2 drivers)
       --feature-gates string              A set of key=value pairs that describe feature gates for alpha/experimental features.
       --force                             Force minikube to perform possibly dangerous operations
       --force-systemd                     If set, force the container runtime to use systemd as cgroup manager. Defaults to false.