:
➜ VBoxManage modifyvm "boot2docker-vm" --natpf1 "tcp-port9000,tcp,,9000,,9000"
VBoxManage: error: The machine 'boot2docker-vm' is already locked for a session (or being unlocked)
VBoxManage: error: Details: code VBOX_E_INVALID_OBJECT_STATE (0x80bb0007), component Machine, interface IMachine, callee nsISupports
VBoxManage: error: Context: "LockMachine(a->session, LockType_Write)" at line 471 of file VBoxManageModifyVM.cpp
, , boot2docker...
1) boot2docker stop
2) VBoxManage modifyvm "boot2docker-vm" --natpf1 "tcp-port9000,tcp,,9000,,9000"
3) boot2docker start