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Virtualbox: move NAT port allocation to machine boot 

The host side ssh NAT port was being chosen by the OS
when the VM was crafted in the `Create` method.
There was no accounting for some other process taking
over the port while the VM is shutoff.

This moves the port provisioning to VM start.
On first start, the OS will supply the port.  Subsequent
starts, we see if we can re-use the port, falling back
to delegating the selection to the OS.

Signed-off-by: John Fieber <jrf@ursamaris.org>
This commit is contained in:
John Fieber 2015-04-17 10:51:28 -07:00
parent cade150461
commit fdaa783597
1 changed files with 30 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

43
drivers/virtualbox/virtualbox.go
View File

@ -165,11 +165,6 @@ func (d *Driver) Create() error {
return err
}
d.SSHPort, err = getAvailableTCPPort()
if err != nil {
return err
}
log.Infof("Creating SSH key...")
b2dutils := utils.NewB2dUtils("", "")
@ -237,11 +232,6 @@ func (d *Driver) Create() error {
return err
}
if err := vbm("modifyvm", d.MachineName,
"--natpf1", fmt.Sprintf("ssh,tcp,127.0.0.1,%d,,22", d.SSHPort)); err != nil {
return err
}
hostOnlyNetwork, err := getOrCreateHostOnlyNetwork(
net.ParseIP("192.168.99.1"),
net.IPv4Mask(255, 255, 255, 0),
@ -340,6 +330,10 @@ func (d *Driver) Start() error {
switch s {
case state.Stopped, state.Saved:
d.SSHPort, err = setPortForwarding(d.MachineName, 1, "ssh", "tcp", 22, d.SSHPort)
if err != nil {
return err
}
if err := vbm("startvm", d.MachineName, "--type", "headless"); err != nil {
return err
}
@ -596,10 +590,12 @@ func zeroFill(w io.Writer, n int64) error {
return nil
}
func getAvailableTCPPort() (int, error) {
port := 0
// Select an available port, trying the specified
// port first, falling back on an OS selected port.
func getAvailableTCPPort(port int) (int, error) {
return 56883, nil
for i := 0; i <= 10; i++ {
ln, err := net.Listen("tcp4", "127.0.0.1:0")
ln, err := net.Listen("tcp4", fmt.Sprintf("127.0.0.1:%d", port))
if err != nil {
return 0, err
}
@ -614,8 +610,29 @@ func getAvailableTCPPort() (int, error) {
port = p
return port, nil
}
port = 0 // Throw away the port hint before trying again
time.Sleep(1)
}
time.Sleep(1)
return 0, fmt.Errorf("unable to allocate tcp port")
}
// Setup a NAT port forwarding entry.
func setPortForwarding(machine string, interfaceNum int, mapName, protocol string, guestPort, desiredHostPort int) (int, error) {
actualHostPort, err := getAvailableTCPPort(desiredHostPort)
if err != nil {
return -1, err
}
if desiredHostPort != actualHostPort && desiredHostPort != 0 {
log.Debugf("NAT forwarding host port for guest port %d (%s) changed from %d to %d",
guestPort, mapName, desiredHostPort, actualHostPort)
}
cmd := fmt.Sprintf("--natpf%d", interfaceNum)
vbm("modifyvm", machine, cmd, "delete", mapName)
if err := vbm("modifyvm", machine,
cmd, fmt.Sprintf("%s,%s,127.0.0.1,%d,,%d", mapName, protocol, actualHostPort, guestPort)); err != nil {
return -1, err
}
return actualHostPort, nil
}