Introduce 'Starting' status for machines

- The State() function now returns machine.Starting status instead of an
  empty string if the VM is in the process of starting.

- The `CheckExclusiveActiveVM()` function returns `true` to prevent
  starting a VM while another is in the process of starting.

- `podman machine ls` displays "Currently starting" under "Last Up" for
  the starting VM

- `podman machine ls` supports `{{.Starting}}` boolean field in the format

- `podman machine inspect` displays "starting" in the "State" field for
  the starting VM

Signed-off-by: Shane Smith <shane.smith@shopify.com>

2 files changed, 8 insertions, 3 deletions

diff --git a/cmd/podman/machine/list.go b/cmd/podman/machine/list.go
index 5254d50cf..bb14d4a67 100644
--- a/cmd/podman/machine/list.go
+++ b/cmd/podman/machine/list.go
@@ -48,6 +48,7 @@ type ListReporter struct {
 	Default        bool
 	Created        string
 	Running        bool
+	Starting       bool
 	LastUp         string
 	Stream         string
 	VMType         string
@@ -224,10 +225,14 @@ func toHumanFormat(vms []*machine.ListResponse) ([]*ListReporter, error) {
 		} else {
 			response.Name = vm.Name
 		}
-		if vm.Running {
+		switch {
+		case vm.Running:
 			response.LastUp = "Currently running"
 			response.Running = true
-		} else {
+		case vm.Starting:
+			response.LastUp = "Currently starting"
+			response.Starting = true
+		default:
 			response.LastUp = units.HumanDuration(time.Since(vm.LastUp)) + " ago"
 		}
 		response.Created = units.HumanDuration(time.Since(vm.CreatedAt)) + " ago"
diff --git a/cmd/podman/machine/start.go b/cmd/podman/machine/start.go
index c9b99e63b..3bd7f4a25 100644
--- a/cmd/podman/machine/start.go
+++ b/cmd/podman/machine/start.go
@@ -56,7 +56,7 @@ func start(_ *cobra.Command, args []string) error {
 		if vmName == activeName {
 			return errors.Wrapf(machine.ErrVMAlreadyRunning, "cannot start VM %s", vmName)
 		}
-		return errors.Wrapf(machine.ErrMultipleActiveVM, "cannot start VM %s. VM %s is currently running", vmName, activeName)
+		return errors.Wrapf(machine.ErrMultipleActiveVM, "cannot start VM %s. VM %s is currently running or starting", vmName, activeName)
 	}
 	fmt.Printf("Starting machine %q\n", vmName)
 	if err := vm.Start(vmName, machine.StartOptions{}); err != nil {