Add file.go and temporary file creation to enable multi instance VM l…

…aunch

Signed-off-by: Darko Draskovic <darko.draskovic@gmail.com>

README.md

@@ -23,7 +23,7 @@ sudo apt update
 sudo apt install qemu-kvm
 ```
 
-Create `img` directory in `cmd/manager`.
+Create `img` directory in `cmd/manager`. Create `tmp` directory in `cmd/manager`.
 
 ### focal-server-cloudimg-amd64.img
 
@@ -50,8 +50,7 @@ MANAGER_QEMU_OVMF_CODE_FILE=/usr/share/OVMF/OVMF_CODE.fd
 
 sudo find / -name OVMF_VARS.fd
 # => /usr/share/OVMF/OVMF_VARS.fd
-cp /usr/share/OVMF/OVMF_VARS.fd .
-MANAGER_QEMU_OVMF_VARS_FILE=img/OVMF_VARS.fd
+MANAGER_QEMU_OVMF_VARS_FILE=/usr/share/OVMF/OVMF_VARS.fd
 ```
 
 ## Run
@@ -74,10 +73,14 @@ Manager will start an HTTP server on port `9021`, and a gRPC server on port `700
 
 ### Create QEMU virtual machine (VM)
 
+To create an instance of VM, run
+
 ```sh
 curl -sSi -X GET http://localhost:9021/qemu
 ```
 
+You should be able to create multiple instances by reruning the command. 
+
 ### Verifying VM launch
 
 NB: To verify that the manager successfully launched the VM, you need to open two terminals on the same machine. In one terminal, you need to launch `go run main.go` (with the environment variables of choice) and in the other, you can run the verification commands.

cmd/manager/main.go

@@ -111,12 +111,6 @@ func main() {
 		logger.Fatal(fmt.Sprintf("failed to load %s QEMU configuration : %s", svcName, err))
 	}
 
-	// exe, args, err := qemu.ExecutableAndArgs(qemuCfg)
-	// if err != nil {
-	// 	logger.Fatal(fmt.Sprintf("failed to generate executable and arguments: %v", err))
-	// }
-	// logger.Info(fmt.Sprintf("%s %s", exe, strings.Join(args, " ")))
-
 	//SVC
 	svc := newService(libvirtConn, agentClient, logger, tracer, qemuCfg)
 
@@ -151,6 +145,11 @@ func main() {
 	if err := g.Wait(); err != nil {
 		logger.Error(fmt.Sprintf("%s service terminated: %s", svcName, err))
 	}
+
+	err = internal.DeleteFilesInDir("tmp/")
+	if err != nil {
+		logger.Error(fmt.Sprintf("%s", err))
+	}
 }
 
 func newService(libvirtConn *libvirt.Libvirt, agent agent.AgentServiceClient, logger logger.Logger, tracer trace.Tracer, qemuCfg qemu.Config) manager.Service {

internal/file.go

@@ -0,0 +1,44 @@
+package internal
+
+import (
+	"io"
+	"os"
+	"path/filepath"
+)
+
+func CopyFile(srcPath, dstPath string) error {
+	src, err := os.Open(srcPath)
+	if err != nil {
+		return err
+	}
+	defer src.Close()
+
+	dst, err := os.Create(dstPath)
+	if err != nil {
+		return err
+	}
+	defer dst.Close()
+
+	_, err = io.Copy(dst, src)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func DeleteFilesInDir(dirPath string) error {
+	files, err := filepath.Glob(filepath.Join(dirPath, "*"))
+	if err != nil {
+		return err
+	}
+
+	for _, file := range files {
+		err := os.Remove(file)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}

manager/qemu/config.go

@@ -20,17 +20,17 @@ type OVMFVarsConfig struct {
 	If     string `env:"OVMF_VARS_IF" envDefault:"pflash"`
 	Format string `env:"OVMF_VARS_FORMAT" envDefault:"raw"`
 	Unit   int    `env:"OVMF_VARS_UNIT" envDefault:"1"`
-	File   string `env:"OVMF_VARS_FILE" envDefault:"img/OVMF_VARS.fd"`
+	File   string `env:"OVMF_VARS_FILE" envDefault:"/usr/share/OVMF/OVMF_VARS.fd"`
 }
 
 type NetDevConfig struct {
 	ID        string `env:"NETDEV_ID" envDefault:"vmnic"`
-	HostFwd1  string `env:"HOST_FWD_1" envDefault:"2222"`
-	GuestFwd1 string `env:"GUEST_FWD_1" envDefault:"22"`
-	HostFwd2  string `env:"HOST_FWD_2" envDefault:"9301"`
-	GuestFwd2 string `env:"GUEST_FWD_2" envDefault:"9031"`
-	HostFwd3  string `env:"HOST_FWD_3" envDefault:"7020"`
-	GuestFwd3 string `env:"GUEST_FWD_3" envDefault:"7002"`
+	HostFwd1  int    `env:"HOST_FWD_1" envDefault:"2222"`
+	GuestFwd1 int    `env:"GUEST_FWD_1" envDefault:"22"`
+	HostFwd2  int    `env:"HOST_FWD_2" envDefault:"9301"`
+	GuestFwd2 int    `env:"GUEST_FWD_2" envDefault:"9031"`
+	HostFwd3  int    `env:"HOST_FWD_3" envDefault:"7020"`
+	GuestFwd3 int    `env:"GUEST_FWD_3" envDefault:"7002"`
 }
 
 type VirtioNetPciConfig struct {
@@ -150,7 +150,7 @@ func constructQemuArgs(config Config) []string {
 
 	// network
 	args = append(args, "-netdev",
-		fmt.Sprintf("user,id=%s,hostfwd=tcp::%s-:%s,hostfwd=tcp::%s-:%s,hostfwd=tcp::%s-:%s",
+		fmt.Sprintf("user,id=%s,hostfwd=tcp::%d-:%d,hostfwd=tcp::%d-:%d,hostfwd=tcp::%d-:%d",
 			config.NetDevConfig.ID,
 			config.NetDevConfig.HostFwd1, config.NetDevConfig.GuestFwd1,
 			config.NetDevConfig.HostFwd2, config.NetDevConfig.GuestFwd2,

manager/service.go

@@ -13,11 +13,15 @@ import (
 
 	"github.com/digitalocean/go-libvirt"
 	"github.com/ultravioletrs/agent/agent"
+	"github.com/ultravioletrs/manager/internal"
 	"github.com/ultravioletrs/manager/manager/qemu"
 
 	"github.com/gofrs/uuid"
 )
 
+const firmwareVars = "OVMF_VARS"
+const qcow2Img = "focal-server-cloudimg-amd64"
+
 var (
 	// ErrMalformedEntity indicates malformed entity specification (e.g.
 	// invalid username or password).
@@ -89,6 +93,7 @@ func (ms *managerService) CreateLibvirtDomain(ctx context.Context, poolXML, volX
 }
 
 func (ms *managerService) CreateQemuVM(ctx context.Context) (*exec.Cmd, error) {
+	// create unique emu device identifiers
 	id, err := uuid.NewV4()
 	if err != nil {
 		return &exec.Cmd{}, err
@@ -99,15 +104,38 @@ func (ms *managerService) CreateQemuVM(ctx context.Context) (*exec.Cmd, error) {
 	qemuCfg.VirtioScsiPciConfig.ID = fmt.Sprintf("%s-%s", qemuCfg.VirtioScsiPciConfig.ID, id)
 	qemuCfg.SevConfig.ID = fmt.Sprintf("%s-%s", qemuCfg.SevConfig.ID, id)
 
-	exe, args, err := qemu.ExecutableAndArgs(qemuCfg)
+	// copy firmware vars file
+	srcFile := qemuCfg.OVMFVarsConfig.File
+	dstFile := fmt.Sprintf("tmp/%s-%s.fd", firmwareVars, id)
+	err = internal.CopyFile(srcFile, dstFile)
+	if err != nil {
+		return &exec.Cmd{}, err
+	}
+	qemuCfg.OVMFVarsConfig.File = dstFile
+
+	// copy qcow2 img file
+	srcFile = qemuCfg.DiskImgConfig.File
+	dstFile = fmt.Sprintf("tmp/%s-%s.img", qcow2Img, id)
+	err = internal.CopyFile(srcFile, dstFile)
 	if err != nil {
 		return &exec.Cmd{}, err
 	}
+	qemuCfg.DiskImgConfig.File = dstFile
 
+	exe, args, err := qemu.ExecutableAndArgs(qemuCfg)
+	if err != nil {
+		return &exec.Cmd{}, err
+	}
 	cmd, err := qemu.RunQemuVM(exe, args)
 	if err != nil {
 		return cmd, err
 	}
+
+	// different VM guests can't forward ports to the same ports on the same host
+	ms.qemuCfg.NetDevConfig.HostFwd1++
+	ms.qemuCfg.NetDevConfig.HostFwd2++
+	ms.qemuCfg.NetDevConfig.HostFwd3++
+
 	return cmd, nil
 }