Patent Publication Number: US-9846591-B2

Title: Method, device and system for migrating configuration information during live migration of virtual machine

Description:
This application is a continuation of U.S. patent application Ser. No. 14/028,073, filed on Sep. 16, 2013, now U.S. Pat. No. 9,323,554. The U.S. patent application Ser. No. 14/028,073 claims priority to Chinese Patent Application No. 201210440895.1, filed on Nov. 7, 2012, the afore-mentioned patent applications are hereby incorporated by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to the field of communications technologies, and in particular to a method, a device, and a system for migrating configuration information during live migration of a virtual machine. 
     BACKGROUND 
     Live migration of a virtual machine means that a virtual machine in a running state migrates from one physical host to another physical host. 
     To maintain secure running of a virtual machine, for each virtual machine, a dynamic host configuration protocol snooping (DHCP SNOOPING) binding table needs to be stored on a forwarding switch that controls the virtual machine, where the binding table records configuration information required for live migration of the virtual machine. Unreliable DHCP configuration information is filtered out by using the binding table, thereby ensuring secure running of the virtual machine. 
     A DHCP SNOOPING feature is incompatible with a mechanism of live migration of a virtual machine; when live migration occurs, a virtual machine itself cannot sense the live migration, and therefore the virtual machine to which the live migration occurs does not actively initiate a DHCP procedure; after the virtual machine migrates to another physical host, no DHCP SNOOPING binding table is stored on a forwarding switch that controls the physical host; and in this case, after the live migration, the virtual machine is online on a new physical host, which is identified as an Internet protocol/media access control (IP/MAC) address forgery attack, thereby causing that the virtual machine fails to access a network. 
     SUMMARY 
     An embodiment of the present disclosure provides a method for migrating configuration information during live migration of a virtual machine, so that configuration information of a virtual machine can be migrated synchronously during live migration of the virtual machine, which enables the virtual machine to access a network successfully after the live migration. Embodiments of the present disclosure further provide a corresponding apparatus and system. 
     In a first aspect, an embodiment of the present disclosure provides a method for migrating configuration information during live migration of a virtual machine. The method includes, after receiving a message of live migration that a virtual machine migrates from a source physical host to a target physical host sent by a virtual machine management server, acquiring an identifier of a source forwarding switch of the virtual machine and an identifier of a target forwarding switch of the virtual machine. The method also includes sending prestored configuration information to the target forwarding switch corresponding to the identifier of the target forwarding switch, so that the target forwarding switch stores the configuration information; and sending a configuration information deletion instruction to the source forwarding switch corresponding to the identifier of the source forwarding switch, so that the source forwarding switch deletes the prestored configuration information. 
     In combination with the first aspect, in a first possible implementation manner, the message of the live migration carries an identifier of the virtual machine to which the live migration occurs and an identifier of the target physical host to which the virtual machine migrates. The acquiring an identifier of a source forwarding switch of the virtual machine and an identifier of a target forwarding switch of the virtual machine specifically includes determining the identifier of the source forwarding switch according to the identifier of the virtual machine; and determining the identifier of the target forwarding switch according to the identifier of the target physical host. 
     In combination with the first aspect, in a second possible implementation manner, the message of the live migration carries an identifier of the virtual machine to which the live migration occurs and an identifier of a target forwarding switch corresponding to the target physical host to which the virtual machine migrates. The acquiring an identifier of a source forwarding switch of the virtual machine and an identifier of a target forwarding switch of the virtual machine specifically includes determining the identifier of the source forwarding switch according to the identifier of the virtual machine. 
     In combination with the first aspect and the first or second possible implementation manner of the first aspect, in a third possible implementation manner, before the step of receiving a message of live migration that a virtual machine migrates from a source physical host to a target physical host sent by a virtual machine management server, the method further includes: creating and storing configuration information; and sending the configuration information to the source forwarding switch. 
     In combination with the first aspect and the first or second possible implementation manner of the first aspect, in a fourth possible implementation manner, before the step of receiving a message of live migration that a virtual machine migrates from a source physical host to a target physical host sent by a virtual machine management server, the method further includes: receiving and storing configuration information created by the source forwarding switch. 
     In combination with the first aspect and the first or second possible implementation manner of the first aspect, in a fifth possible implementation manner, before the step of receiving a message of live migration that a virtual machine migrates from a source physical host to a target physical host sent by a virtual machine management server, the method further includes: receiving configuration information of the virtual machine sent by the virtual machine management server, and sending the configuration information of the virtual machine to the source forwarding switch. 
     In combination with the fifth possible implementation manner of the first aspect, in a sixth possible implementation manner, after the step of receiving a message of live migration that a virtual machine migrates from a source physical host to a target physical host sent by a virtual machine management server, the method further includes: receiving and storing updated configuration information that is sent by the virtual machine management server after the live migration of the virtual machine. The sending prestored configuration information to the target forwarding switch corresponding to the identifier of the target forwarding switch specifically includes: sending the updated configuration information to the target forwarding switch. 
     In a second aspect, an embodiment of the present disclosure provides a switching control apparatus. The apparatus includes a receiving unit, configured to receive a message of live migration that a virtual machine migrates from a source physical host to a target physical host sent by a virtual machine management server. Also included is an acquiring unit, configured to acquire an identifier of a source forwarding switch of the virtual machine and an identifier of a target forwarding switch of the virtual machine after the receiving unit receives the message of the live migration of the virtual machine. Also included is a sending unit, configured to send prestored configuration information to the target forwarding switch corresponding to the identifier of the target forwarding switch, where the identifier of the target forwarding switch is acquired by the acquiring unit, so that the target forwarding switch stores the configuration information; and send a configuration information deletion instruction to the source forwarding switch corresponding to the identifier of the source forwarding switch, so that the source forwarding switch deletes the prestored configuration information. 
     In combination with the second aspect, in a first possible implementation manner, the message of the live migration carries an identifier of the virtual machine to which the live migration occurs and an identifier of the target physical host to which the virtual machine migrates. The acquiring unit is specifically configured to determine the identifier of the source forwarding switch according to the identifier of the virtual machine and determine the identifier of the target forwarding switch according to the identifier of the target physical host. 
     In combination with the second aspect, in a second possible implementation manner, the message of the live migration carries an identifier of the virtual machine to which the live migration occurs and an identifier of a target forwarding switch corresponding to the target physical host to which the virtual machine migrates. The acquiring unit is specifically configured to determine the identifier of the source forwarding switch according to the identifier of the virtual machine. 
     In combination with the second aspect and the first or second possible implementation manner of the second aspect, in a third possible implementation manner, the switching control apparatus further includes: a creating unit and a first storing unit. The creating unit is configured to create configuration information. The first storing unit is configured to store the configuration information created by the creating unit. The sending unit is further configured to send, to the source forwarding switch, the configuration information stored by the first storing unit. 
     In combination with the second aspect and the first or second possible implementation manner of the second aspect, in a fourth possible implementation manner, the switching control apparatus further includes: a second storing unit. The receiving unit is further configured to receive configuration information created by the source forwarding switch, and the second storing unit is configured to store the configuration information received by the receiving unit. 
     In combination with the second aspect and the first or second possible implementation manner of the second aspect, in a fifth possible implementation manner: the receiving unit is further configured to receive configuration information of the virtual machine sent by the virtual machine management server. The sending unit is further configured to send, to the source forwarding switch, the configuration information of the virtual machine received by the receiving unit. 
     In combination with the fifth possible implementation manner, in a sixth possible implementation manner: the receiving unit is further configured to receive updated configuration information that is sent by the virtual machine management server after the live migration of the virtual machine. The sending unit is further configured to send, to the target forwarding switch, the updated configuration information received by the receiving unit. 
     In a third aspect, an embodiment of the present disclosure provides a computer storage medium. The computer storage medium stores a program, and when the program is executed, a part or all of the steps in the information configuration method are performed. 
     In a fourth aspect, an embodiment of the present disclosure provides a switching control device, including: an input apparatus, an output apparatus, a memory, and a processor, where: the input apparatus is configured to receive a message of live migration that a virtual machine migrates from a source physical host to a target physical host sent by a virtual machine management server; the processor is configured to acquire an identifier of a source forwarding switch of the virtual machine and an identifier of a target forwarding switch of the virtual machine; and the output apparatus is configured to send prestored configuration information to the target forwarding switch corresponding to the identifier of the target forwarding switch, so that the target forwarding switch stores the configuration information; and send a configuration information deletion instruction to the source forwarding switch corresponding to the identifier of the source forwarding switch, so that the source forwarding switch deletes the prestored configuration information. 
     In combination with the fourth aspect, in a first possible implementation manner, the message of the live migration carries an identifier of the virtual machine to which the live migration occurs and an identifier of the target physical host to which the virtual machine migrates, and the processor is configured to determine the identifier of the source forwarding switch according to the identifier of the virtual machine and determine the identifier of the target forwarding switch according to the identifier of the target physical host. 
     In combination with the fourth aspect, in a second possible implementation manner, the message of the live migration carries an identifier of the virtual machine to which the live migration occurs and an identifier of a target forwarding switch corresponding to the target physical host to which the virtual machine migrates, and the processor is configured to determine the identifier of the source forwarding switch according to the identifier of the virtual machine. 
     In combination with the fourth aspect and the first or second possible implementation manner of the fourth aspect, in a third possible implementation manner: the processor is further configured to create configuration information; the memory is further configured to store the configuration information; and the output apparatus is further configured to send the configuration information to the source forwarding switch. 
     In combination with the fourth aspect and the first or second possible implementation manner of the fourth aspect, in a fourth possible implementation manner: the input apparatus is further configured to receive configuration information created by the source forwarding switch; and the memory is further configured to store the configuration information. 
     In combination with the fourth aspect and the first or second possible implementation manner of the fourth aspect, in a fifth possible implementation manner: the input apparatus is further configured to receive configuration information of the virtual machine sent by the virtual machine management server; and the output apparatus is further configured to send the configuration information of the virtual machine to the source forwarding switch. 
     In combination with the fifth possible implementation manner, in a sixth possible implementation manner, the input apparatus is further configured to receive updated configuration information that is sent by the virtual machine management server after the live migration of the virtual machine; and the output apparatus is further configured to send the updated configuration information to the target forwarding switch. 
     In a fifth aspect, an embodiment of the present disclosure provides a virtual network system, including: a virtual machine, a physical host, a forwarding switch, a virtual machine management server, and a switching control apparatus. The physical host communicates with the virtual machine management server through an H1 interface, the forwarding switch communicates with the switching control apparatus through a C1 interface, and the virtual machine management server communicates with the switching control apparatus through an I1 interface. The virtual machine runs on the physical host, the virtual machine management server manages the virtual machine, and the forwarding switch supports running of the virtual machine. The switching control apparatus is the switching control apparatus in the foregoing technical solution. 
     In the embodiments of the present disclosure, after a message of live migration that a virtual machine migrates from a source physical host to a target physical host sent by a virtual machine management server is received, an identifier of a source forwarding switch of the virtual machine and an identifier of a target forwarding switch of the virtual machine are acquired. Prestored configuration information is sent to the target forwarding switch corresponding to the identifier of the target forwarding switch, so that the target forwarding switch stores the configuration information. A configuration information deletion instruction is sent to the source forwarding switch corresponding to the identifier of the source forwarding switch, so that the source forwarding switch deletes the prestored configuration information. Compared with the prior art in which configuration information is not migrated synchronously after live migration of a virtual machine, with the method for migrating configuration information during live migration of a virtual machine provided in the embodiments of the present disclosure, configuration information of a virtual machine can be migrated synchronously during live migration of the virtual machine. In this way, when the virtual machine is online on a new physical host, it is not identified as an Internet protocol/media access control address forgery attack, thereby enabling the virtual machine to access a network successfully after the live migration. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: 
       To describe the technical solutions in the embodiments of the present disclosure more clearly, the following briefly introduces the accompanying drawings required for describing the embodiments. Apparently, the accompanying drawings in the following description show merely some embodiments of the present disclosure, and persons of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative efforts. 
         FIG. 1  is a schematic diagram of an embodiment of a method according to the present disclosure; 
         FIG. 2  is a schematic diagram of an embodiment of an application scenario according to the present disclosure; 
         FIG. 3  is a schematic diagram of another embodiment of an application scenario according to the present disclosure; 
         FIG. 4  is a schematic diagram of another embodiment of an application scenario according to the present disclosure; 
         FIG. 5  is a schematic diagram of another embodiment of an application scenario according to the present disclosure; 
         FIG. 6  is a schematic diagram of an embodiment of a switching control apparatus according to the present disclosure; 
         FIG. 7  is a schematic diagram of another embodiment of a switching control apparatus according to the present disclosure; 
         FIG. 8  is a schematic diagram of another embodiment of a switching control apparatus according to the present disclosure; 
         FIG. 9  is a schematic diagram of another embodiment of a switching control apparatus according to the present disclosure; 
         FIG. 10  is a schematic diagram of an embodiment of a switching control device according to the present disclosure; and 
         FIG. 11  is a schematic diagram of an embodiment of a virtual system according to the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
     An embodiment of the present disclosure provides a method for migrating configuration information during live migration of a virtual machine, so that configuration information of a virtual machine can be migrated synchronously during live migration of the virtual machine, which enables the virtual machine to access a network successfully after the live migration. Embodiments of the present disclosure further provide a corresponding apparatus and system, which are described in detail in the following. 
     The following clearly describes the technical solutions in the embodiments of the present disclosure with reference to the accompanying drawings in the embodiments of the present disclosure. Apparently, the embodiments to be described are merely a part rather than all of the embodiments of the present disclosure. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present disclosure without creative efforts shall fall within the protection scope of the present disclosure. 
     Referring to  FIG. 1 , an embodiment of a method for migrating configuration information during live migration of a virtual machine provided in embodiment of the present disclosure includes the following steps. 
       101 . After receiving a message of live migration that a virtual machine migrates from a source physical host to a target physical host sent by a virtual machine management server, a switching control apparatus acquires an identifier of a source forwarding switch of the virtual machine and an identifier of a target forwarding switch of the virtual machine. 
     After the virtual machine migrates from the source physical host to the target physical host, the virtual machine management server detects a live migration event through communication interfaces between the virtual machine management server and the physical hosts, where the communication interfaces between the virtual machine management server and the physical hosts may be H1 interfaces. After detecting that live migration occurs to the virtual machine, the virtual machine management server sends a message of the live migration of the virtual machine to the switching control apparatus through a communication interface between the virtual machine management server and the switching control apparatus, where the communication interface between the virtual machine management server and the switching control apparatus may be an I1 interface. 
       102 . The switching control apparatus sends prestored configuration information to the target forwarding switch corresponding to the identifier of the target forwarding switch, so that the target forwarding switch stores the configuration information. 
     After the virtual machine migrates to the target physical host in a live manner, the virtual machine can normally access a network only when a target forwarding switch that controls the target physical host needs to have configuration information that is required for the virtual machine to access the network. Therefore, the switching control apparatus needs to send the configuration information that is required for the virtual machine to access the network to the target forwarding switch, so that the target forwarding switch stores the configuration information and the virtual machine normally accesses the network. 
       103 . The switching control apparatus sends a configuration information deletion instruction to the source forwarding switch corresponding to the identifier of the source forwarding switch, so that the source forwarding switch deletes the prestored configuration information. 
     After the live migration occurs to the virtual machine, if the source forwarding switch of the virtual machine still stores the configuration information of the virtual machine, a network anomaly is caused. Therefore, the switching control apparatus may send the configuration information deletion instruction to the source forwarding switch corresponding to the identifier of the source forwarding switch, so that the source forwarding switch deletes the prestored configuration information. 
     The configuration information may include: a media access control (MAC) address, an Internet protocol (IP) address, and the like. Specific content of the configuration information may be shown in the form of a dynamic host configuration protocol snooping (DHCP SNOOPING) binding table. Content in the DHCP SNOOPING binding table may be sent when the configuration information is sent. 
     In this embodiment of the present disclosure, after a message of live migration that a virtual machine migrates from a source physical host to a target physical host sent by a virtual machine management server is received, an identifier of a source forwarding switch of the virtual machine and an identifier of a target forwarding switch of the virtual machine are acquired. Prestored configuration information is sent to the target forwarding switch corresponding to the identifier of the target forwarding switch, so that the target forwarding switch stores the configuration information. A configuration information deletion instruction is sent to the source forwarding switch corresponding to the identifier of the source forwarding switch, so that the source forwarding switch deletes the prestored configuration information. Compared with the prior art in which configuration information is not migrated synchronously after live migration of a virtual machine, with the method for migrating configuration information during live migration of a virtual machine provided in this embodiment of the present disclosure, configuration information of a virtual machine can be migrated synchronously during live migration of the virtual machine. In this way, when the virtual machine is online on a new physical host, it is not identified as an Internet protocol/media access control address forgery attack, thereby enabling the virtual machine to access a network successfully after the live migration. 
     Optionally, based on the embodiment corresponding to  FIG. 1 , in another embodiment of the method for migrating configuration information during live migration of a virtual machine provided. In this embodiment of the present disclosure, the message of the live migration carries an identifier of the virtual machine to which the live migration occurs and an identifier of the target physical host to which the virtual machine migrates. The acquiring an identifier of a source forwarding switch of the virtual machine and an identifier of a target forwarding switch of the virtual machine specifically includes: determining the identifier of the source forwarding switch according to the identifier of the virtual machine; and determining the identifier of the target forwarding switch according to the identifier of the target physical host. 
     In this embodiment of the present disclosure, the switching control apparatus may store a mapping table of the identifier of the virtual machine and the identifier of the source forwarding switch and a mapping table of the identifier of the target physical host and the identifier of the target forwarding switch, and correspondence may be determined through the mapping tables. 
     Optionally, based on the embodiment corresponding to  FIG. 1 , in another embodiment of the method for migrating configuration information during live migration of a virtual machine provided in this embodiment of the present disclosure, the message of the live migration carries an identifier of the virtual machine to which the live migration occurs and an identifier of a target forwarding switch corresponding to the target physical host to which the virtual machine migrates. The acquiring an identifier of a source forwarding switch of the virtual machine and an identifier of a target forwarding switch of the virtual machine specifically includes: determining the identifier of the source forwarding switch according to the identifier of the virtual machine. 
     Optionally, based on the embodiment corresponding to  FIG. 1  and the optional embodiments corresponding to  FIG. 1 , in another embodiment of the method for migrating configuration information during live migration of a virtual machine provided in this embodiment of the present disclosure: before the step of receiving a message of live migration that a virtual machine migrates from a source physical host to a target physical host sent by a virtual machine management server, the method further includes: creating and storing configuration information; and sending the configuration information to the source forwarding switch. 
     Optionally, based on the embodiment corresponding to  FIG. 1  and the optional embodiments corresponding to  FIG. 1 , in another embodiment of the method for migrating configuration information during live migration of a virtual machine provided in this embodiment of the present disclosure: before the step of receiving a message of live migration that a virtual machine migrates from a source physical host to a target physical host sent by a virtual machine management server, the method further includes: receiving and storing configuration information created by the source forwarding switch. 
     Optionally, based on the embodiment corresponding to  FIG. 1  and the optional embodiments corresponding to  FIG. 1 , in another embodiment of the method for migrating configuration information during live migration of a virtual machine provided in this embodiment of the present disclosure, before the step of receiving a message of live migration that a virtual machine migrates from a source physical host to a target physical host sent by a virtual machine management server, the method further includes: receiving configuration information of the virtual machine sent by the virtual machine management server, and sending the configuration information of the virtual machine to the source forwarding switch. After the step of receiving a message of live migration that a virtual machine migrates from a source physical host to a target physical host sent by a virtual machine management server, the method further includes: receiving and storing updated configuration information that is sent by the virtual machine management server after the live migration of the virtual machine. The sending prestored configuration information to the target forwarding switch corresponding to the identifier of the target forwarding switch specifically includes: sending the updated configuration information to the target forwarding switch. 
     For ease of understanding, the method for migrating configuration information during live migration of a virtual machine according to this embodiment of the present disclosure is described in detail by taking several specific application scenarios as examples in the following. 
     Referring to  FIG. 2 , a first virtual machine  610  and a second virtual machine  620  run on a first physical host  60 , a third virtual machine  710  runs on a second physical host  70 , a first forwarding switch  40  stores configuration information that is required for the first virtual machine  610  and the second virtual machine  620  to access a network, a second forwarding switch  50  stores configuration information that is required for the third virtual machine  710  to access a network, a virtual machine management server  30  communicates with the first physical host  60  and the second physical host  70  through H1 interfaces and monitors a live migration situation of a virtual machine through the H1 interfaces, the virtual machine management server  30  communicates with a switching control apparatus  20  through an I1 interface, the virtual machine management server  30  notifies, through the I1 interface, the switching control apparatus  20  of a message indicating that live migration occurs to a virtual machine, and the switching control apparatus  20  communicates with the first forwarding switch  40  and the second forwarding switch  50  through C1 interfaces. 
     In this embodiment of the present disclosure, it is assumed that live migration occurs to the first virtual machine  610 . After detecting a live migration event, the virtual machine management server  30  sends, to the switching control apparatus  20 , a message indicating that live migration occurs to the virtual machine  610 , and carries an identifier of the virtual machine  610  and an identifier of a target physical host in the message of the live migration. When the target physical host is the second physical host, an identifier of the second physical host  70  is carried. If the virtual machine management server  30  stores a mapping table of a physical host and a forwarding switch, the message of the live migration may directly carry the identifier of the virtual machine  610  and an identifier of a target forwarding switch. The target forwarding switch in this embodiment is the second forwarding switch, and an identifier of the second forwarding switch  50  is carried. After receiving the message of the live migration, the switching control apparatus  20  determines a source forwarding switch as the first forwarding switch and an identifier of the source forwarding switch as an identifier of the first forwarding switch  40  according to the identifier of the virtual machine  610 ; and determines the identifier of the target forwarding switch as the identifier of the second forwarding switch  50  according to an identifier of the target physical host, that is, the identifier of the second physical host  70 . To understand specific procedures of determining the source forwarding switch and the target forwarding switch, reference may be made to Table 1 and Table 2: 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Description of C1 interface parameters stored in a switching control apparatus 
               
            
           
           
               
               
            
               
                 Parameter Name 
                 Function Description 
               
               
                   
               
               
                 MAC address 
                 Multimedia access control address of a virtual machine: This 
               
               
                   
                 address may be configured when a user uses the virtual machine or 
               
               
                   
                 specified when an administrator creates the virtual machine. If it is 
               
               
                   
                 inconsistent with a received packet on a network, MAC address 
               
               
                   
                 spoofing is identified. 
               
               
                 IP address 
                 Internet protocol address of the virtual machine: It is dynamically 
               
               
                   
                 assigned by a DHCP server or statically assigned by a virtual 
               
               
                   
                 machine management server. If it is inconsistent with a received 
               
               
                   
                 packet on a network, IP address spoofing is identified. 
               
               
                 Lease 
                 The DHCP server allocates a subscription duration of an IP address. 
               
               
                   
                 This entry is automatically released/deleted in the case of timeout. 
               
               
                 Type 
                 It identifies whether the IP address is dynamically assigned by the 
               
               
                   
                 DHCP server or statically configured by a virtual management 
               
               
                   
                 platform. 
               
               
                 VLAN 
                 A label of a virtual local area network to which a specified virtual 
               
               
                   
                 machine belongs 
               
               
                 Port 
                 A number of an interface through which a forwarding switch 
               
               
                   
                 communicates with a specified virtual machine 
               
               
                 VM ID 
                 An identifier of the virtual machine: In the case in which the MAC 
               
               
                   
                 address of the virtual machine is changeable, an ID of the virtual 
               
               
                   
                 machine may replace the MAC address. 
               
               
                 Forwarding switch ID 
                 An identifier of a forwarding switch: It identifies a forwarding 
               
               
                   
                 switch corresponding to a physical host where a specified virtual 
               
               
                   
                 machine is located (A switching control apparatus determines the 
               
               
                   
                 forwarding switch ID according to an ID of the physical host.) 
               
               
                 Port status 
                 Interface status: UP/DOWN/DISABLE. It identifies that a specified 
               
               
                   
                 interface is in an “up”, “down”, or “disable” state. 
               
               
                 Port security 
                 TRUST/UNTRUST. It indicates an interface security attribute 
               
               
                   
                 defined in DHCP snooping. 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Description of I1 interface parameters 
               
            
           
           
               
               
            
               
                 Parameter Name 
                 Function Description 
               
               
                   
               
               
                 VM ID 
                 An identifier of a virtual machine: In the case in which a MAC 
               
               
                   
                 address of the virtual machine is changeable, the VM ID replaces 
               
               
                   
                 the MAC address. 
               
               
                 MAC address 
                 The MAC address of the virtual machine: This address may be 
               
               
                   
                 configured when a user uses the virtual machine or specified when 
               
               
                   
                 an administrator creates the virtual machine. 
               
               
                 IP address 
                 IP address of the virtual machine: It is dynamically assigned by a 
               
               
                   
                 DHCP server or statically assigned by a virtual management 
               
               
                   
                 platform. 
               
               
                 ID of a source physical 
                 It identifies which host from which a specified virtual machine 
               
               
                 host 
                 migrates. An entry built in a switching control apparatus identifies a 
               
               
                   
                 mapping between an ID of a source physical host and an ID of a 
               
               
                   
                 source forwarding switch. 
               
               
                 ID of a target physical 
                 It is used to identify which target host into which a specified virtual 
               
               
                 host 
                 machine is embedded. An entry built in the switching control 
               
               
                   
                 apparatus identifies a mapping between an ID of a target physical 
               
               
                   
                 host and an ID of a target forwarding switch. 
               
               
                   
               
            
           
         
       
     
     After the source forwarding switch and the target forwarding switch are determined, the stored configuration information is sent to the target forwarding switch, that is, the second forwarding switch  50 , so that the second forwarding switch  50  stores the configuration information, and a configuration information deletion instruction is sent to the source forwarding switch, that is, the first forwarding switch  40 , so that the first forwarding switch  40  deletes the stored configuration information. 
     Referring to  FIG. 3 , the method for migrating configuration information during live migration of a virtual machine in this embodiment of the present disclosure is described in detail, which is specifically as follows. 
     S 100 . A virtual machine sends a dynamic host configuration protocol DHCP request to a first forwarding switch. 
     S 105 . The first forwarding switch receives a DHCP response from a DHCP server after forwarding the DHCP request to the DHCP server. 
     S 110 . The first forwarding switch synchronizes response time of the DHCP request to a switching control apparatus. 
     S 115 . The switching control apparatus generates configuration information of the virtual machine. 
     S 120 . The switching control apparatus sends the configuration information to the first forwarding switch for the first forwarding switch to maintain normal running of the virtual machine. 
     S 125 . A virtual machine management server detects that live migration occurs to the virtual machine. 
     S 130 . The virtual machine management server sends a message of the live migration to the switching control apparatus, where the message of the live migration carries an identifier of the virtual machine and an identifier of a second forwarding switch. 
     S 135 . The switching control apparatus sends the configuration information of the virtual machine to the second forwarding switch. 
     S 140 . The switching control apparatus sends a configuration information deletion instruction to the first forwarding switch, so as to save memory of the first forwarding switch. 
     Referring to  FIG. 4 , the method for migrating configuration information during live migration of a virtual machine in this embodiment of the present disclosure is described in detail, which is specifically as follows. 
     S 200 . A virtual machine sends a dynamic host configuration protocol DHCP request to a first forwarding switch, and the first forwarding switch returns a DHCP response to the virtual machine. 
     S 205 . The first forwarding switch generates configuration information of the virtual machine. 
     S 210 . The first forwarding switch sends the configuration information of the virtual machine to a switching control apparatus. 
     S 215 . A virtual machine management server detects that live migration occurs to the virtual machine. 
     S 220 . The virtual machine management server sends a message of the live migration to the switching control apparatus, where the message of the live migration carries an identifier of the virtual machine and an identifier of a second forwarding switch. 
     S 225 . The switching control apparatus sends the configuration information of the virtual machine to the second forwarding switch. 
     S 230 . The switching control apparatus sends a configuration information deletion instruction to the first forwarding switch, so as to save memory of the first forwarding switch. 
     Referring to  FIG. 5 , the method for migrating configuration information during live migration of a virtual machine in this embodiment of the present disclosure is described in detail, which is specifically as follows: 
     S 300 . A virtual machine management server creates a virtual machine. 
     S 305 . The virtual machine management server starts the virtual machine. 
     S 310 . The virtual machine management server sends configuration information of the virtual machine to a switching control apparatus. 
     S 315 . The switching control apparatus sends the configuration information of the virtual machine to a first forwarding switch. 
     S 320 . The virtual machine is online on the first forwarding switch. 
     S 325 . The virtual machine management server detects that live migration occurs to the virtual machine. 
     S 330 . The virtual machine management server sends updated configuration information of the virtual machine to the switching control apparatus. 
     S 335 . The switching control apparatus sends the updated configuration information of the virtual machine to a second forwarding switch. 
     S 340 . The switching control apparatus sends a configuration information deletion instruction to the first forwarding switch. 
     S 345 . The virtual machine is online on the second forwarding switch. 
     S 350 . The virtual machine is offline from the first forwarding switch. 
     With the method for migrating configuration information during live migration of a virtual machine provided in the foregoing multiple embodiments of the present disclosure, configuration information of a virtual machine can be migrated synchronously during live migration of the virtual machine, thereby enabling the virtual machine to access a network successfully after the live migration. 
     Referring to  FIG. 6 , an embodiment of a switching control apparatus provided in an embodiment of the present disclosure. The apparatus includes a receiving unit  201 , configured to receive a message of live migration that a virtual machine migrates from a source physical host to a target physical host sent by a virtual machine management server. Also included is an acquiring unit  202 , configured to acquire an identifier of a source forwarding switch of the virtual machine and an identifier of a target forwarding switch of the virtual machine after the receiving unit  201  receives the message of the live migration of the virtual machine. Also included is a sending unit  203 , configured to send prestored configuration information to the target forwarding switch corresponding to the identifier of the target forwarding switch, where the identifier of the target forwarding switch is acquired by the acquiring unit  202 , so that the target forwarding switch stores the configuration information; and send a configuration information deletion instruction to the source forwarding switch corresponding to the identifier of the source forwarding switch, so that the source forwarding switch deletes the prestored configuration information. 
     In this embodiment of the present disclosure, a receiving unit  201  receives a message of live migration that a virtual machine migrates from a source physical host to a target physical host sent by a virtual machine management server; an acquiring unit  202  acquires an identifier of a source forwarding switch of the virtual machine and an identifier of a target forwarding switch of the virtual machine after the receiving unit  201  receives the message of the live migration of the virtual machine. A sending unit  203  sends prestored configuration information to the target forwarding switch corresponding to the identifier of the target forwarding switch, where the identifier of the target forwarding switch is acquired by the acquiring unit  202 , so that the target forwarding switch stores the configuration information; and sends a configuration information deletion instruction to the source forwarding switch corresponding to the identifier of the source forwarding switch, so that the source forwarding switch deletes the prestored configuration information. Compared with the prior art, the switching control apparatus provided in this embodiment of the present disclosure can synchronously migrate configuration information of a virtual machine during live migration of the virtual machine. In this way, when the virtual machine is online on a new physical host, it is not identified as an Internet protocol/media access control address forgery attack, thereby enabling the virtual machine to access a network successfully after the live migration. 
     Optionally, based on the embodiment corresponding to  FIG. 6 , in another embodiment of the switching control apparatus provided in this embodiment of the present disclosure, the message of the live migration carries an identifier of the virtual machine to which the live migration occurs and an identifier of the target physical host to which the virtual machine migrates, and the acquiring unit  202  is specifically configured to determine the identifier of the source forwarding switch according to the identifier of the virtual machine and determine the identifier of the target forwarding switch according to the identifier of the target physical host. 
     Optionally, based on the embodiment corresponding to  FIG. 6 , in another embodiment of the switching control apparatus provided in this embodiment of the present disclosure, the message of the live migration carries an identifier of the virtual machine to which the live migration occurs and an identifier of a target forwarding switch corresponding to the target physical host to which the virtual machine migrates, and the acquiring unit is specifically configured to determine the identifier of the source forwarding switch according to the identifier of the virtual machine. 
     Optionally, based on the embodiment corresponding to  FIG. 6 , referring to  FIG. 7 , another embodiment of the switching control apparatus provided in this embodiment of the present disclosure further includes: a creating unit  204  and a first storing unit  205 , where: the creating unit  204  is configured to create configuration information; the first storing unit  205  is configured to store the configuration information created by the creating unit  204 ; and the sending unit  203  is further configured to send, to the source forwarding switch, the configuration information stored by the first storing unit  205 . 
     Optionally, based on the embodiment corresponding to  FIG. 6 , referring to  FIG. 8 , another embodiment of the switching control apparatus provided in this embodiment of the present disclosure further includes: a second storing unit  206 , where: the receiving unit  201  is further configured to receive configuration information created by the source forwarding switch; and the second storing unit  206  is configured to store the configuration information received by the receiving unit  201 . 
     Optionally, based on the embodiment shown in  FIG. 6 , referring to  FIG. 9 , in another embodiment of the switching control apparatus provided in this embodiment of the present disclosure: the receiving unit  201  is further configured to receive configuration information of the virtual machine sent by the virtual machine management server; and the sending unit  203  is further configured to send, to the source forwarding switch, the configuration information of the virtual machine received by the receiving unit  201 . 
     An embodiment of the present disclosure further provides a computer storage medium, where the computer storage medium stores a program, and when the program is executed, a part or all of the steps in the method for migrating configuration information during live migration of a virtual machine are performed. 
     Referring to  FIG. 10 , an embodiment of the present disclosure further provides a switching control device. The device includes an input apparatus  400 , an output apparatus  500 , a memory  600 , and a processor  700 . The input apparatus  400 , the output apparatus  500 , the memory  600 , and the processor  700  are connected through a bus or in another manner. The input apparatus  400  is configured to receive a message of live migration that a virtual machine migrates from a source physical host to a target physical host sent by a virtual machine management server. The processor  700  is configured to acquire an identifier of a source forwarding switch of the virtual machine and an identifier of a target forwarding switch of the virtual machine; and the output apparatus  500  is configured to send prestored configuration information to the target forwarding switch corresponding to the identifier of the target forwarding switch, so that the target forwarding switch stores the configuration information; and send a configuration information deletion instruction to the source forwarding switch corresponding to the identifier of the source forwarding switch, so that the source forwarding switch deletes the prestored configuration information. 
     In some embodiments of the present disclosure, the message of the live migration carries an identifier of the virtual machine to which the live migration occurs and an identifier of the target physical host to which the virtual machine migrates, and the processor  700  is configured to determine the identifier of the source forwarding switch according to the identifier of the virtual machine and determine the identifier of the target forwarding switch according to the identifier of the target physical host. 
     In some embodiments of the present disclosure, the message of the live migration carries an identifier of the virtual machine to which the live migration occurs and an identifier of a target forwarding switch corresponding to the target physical host to which the virtual machine migrates, and the processor  700  is configured to determine the identifier of the source forwarding switch according to the identifier of the virtual machine. 
     In some embodiments of the present disclosure, the processor  700  is further configured to create configuration information; the memory  600  is further configured to store the configuration information; and the output apparatus  500  is further configured to send the configuration information to the source forwarding switch. 
     In some embodiments of the present disclosure, the input apparatus  400  is further configured to receive configuration information created by the source forwarding switch; and the memory  600  is further configured to store the configuration information. 
     In some embodiments of the present disclosure, the input apparatus  400  is further configured to receive configuration information of the virtual machine sent by the virtual machine management server; and the output apparatus  500  is further configured to send the configuration information of the virtual machine to the source forwarding switch. 
     In some embodiments of the present disclosure, the input apparatus  400  is further configured to receive updated configuration information that is sent by the virtual machine management server after the live migration of the virtual machine; and the output apparatus  500  is further configured to send the updated configuration information to the target forwarding switch. 
     Referring to  FIG. 11 , an embodiment of a virtual network system provided in an embodiment of the present disclosure includes: a virtual machine  910 , a physical host  90 , a forwarding switch  80 , a virtual machine management server  30 , and a switching control apparatus  20 , where the physical host  90  communicates with the virtual machine management server  30  through an H1 interface, the forwarding switch  80  communicates with the switching control apparatus  20  through a C1 interface, and the virtual machine management server  30  communicates with the switching control apparatus  20  through an I1 interface; the virtual machine  910  runs on the physical host  90 , the virtual machine management server  30  manages the virtual machine  910 , and the forwarding switch  80  supports running of the virtual machine; and the switching control apparatus  20  is configured to receive a message of live migration that the virtual machine migrates from a source physical host to a target physical host sent by the virtual machine management server, and acquire an identifier of a source forwarding switch of the virtual machine and an identifier of a target forwarding switch of the virtual machine; send prestored configuration information to the target forwarding switch corresponding to the identifier of the target forwarding switch, so that the target forwarding switch stores the configuration information; and send a configuration information deletion instruction to the source forwarding switch corresponding to the identifier of the source forwarding switch, so that the source forwarding switch deletes the prestored configuration information. 
     With the system provided in this embodiment of the present disclosure, configuration information of a virtual machine can be migrated synchronously during live migration of the virtual machine. In this way, when the virtual machine is online on a new physical host, it is not identified as an Internet protocol/media access control address forgery attack, thereby enabling the virtual machine to access a network successfully after the live migration. 
     Persons of ordinary skill in the art may understand that all or a part of the steps of the methods in the foregoing embodiments may be implemented by a program instructing relevant hardware. The program may be stored in a computer readable storage medium. The storage medium may include a ROM, a RAM, a magnetic disk, or an optical disk. 
     The method, apparatus, and system for migrating configuration information during live migration of a virtual machine provided in the embodiments of the present disclosure are described in detail in the foregoing. Specific examples are used for describing principles and implementation manners of the present disclosure in this specification. The foregoing description about the embodiments is merely for helping understand the methods and core ideas of the present disclosure. Meanwhile, persons skilled in the art may make variations to the specific implementation manners and application scopes according to the ideas of the present disclosure. In conclusion, the content of this specification shall not be construed as a limitation on the present disclosure. 
     While this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description. It is therefore intended that the appended claims encompass any such modifications or embodiments.