CN104754033B - The method that virtual machine migrates online is realized based on two-way pipe method under NDN - Google Patents

Abstract

The present invention relates to a method for realizing online migration of a virtual machine based on a two-way pipeline under NDN, comprising the following steps: (1) Name space design step in NDN: defining three name spaces for naming data packets; (2) two-way Pipeline communication steps: data packets are communicated between the data requester and the data sender through a two-way pipeline; the two-way pipeline communication steps include reverse order and packet loss processing: set a buffer area for storing data that arrives in advance or is generated in advance due to reverse order, and uses The timeout retransmission mechanism is used to re-acquire the Data. When the timeout is repeated multiple times, the request is re-requested in the form of sub-packages; (3) Performance test steps. Compared with the prior art, the present invention realizes the online migration of the virtual machine in the local area network and the wide area network under the NDN network, keeps the application on the virtual machine in the process of virtual machine migration, realizes the seamless migration of the virtual machine, and The dynamic self-adaptation mechanism is used to ensure that the network is smooth after the migration is completed.

Description

Method of Realizing Online Migration of Virtual Machine Based on Two-way Pipeline under NDN

technical field

The present invention relates to the field of network communication technology and cloud computing technology, and in particular to a method for realizing online migration of a virtual machine based on a bidirectional pipeline under NDN (Named Data Networking).

Background technique

With the development of the network, more and more limitations have appeared in the TCP/IP structure, including scalability, stability, security and mobility. These shortcomings have led the academic community to start research on future networks. FIA-NP currently has three main projects: MobilityFirst-NP, Named Data Networking-NP, and eXpressive Internet Architecture (XIA). Among them, the core concept of NDN is that the network does not focus on location (Where), but data (What). This transformation not only greatly improves the flexibility, scalability and mobility of the network, but also the built-in security strategy Improve the security of the network and its applications.

As a representative of data-oriented networks, NDN has launched research and deployed test platforms around the world. At present, NDN research has entered the next stage, mainly focusing on the design of NDN applications, security, routing and forwarding strategies, scalable forwarding, library and tool development, social and economic impact, etc. NDN only contains two kinds of data packets, Interest and Data. It is a network driven by the receiver. The data requester in NDN is called the consumer, and the data sender is called the producer. Communication network architecture. In order to receive data, a consumer sends an Interest message, which carries a name, and the name identifies the desired data. After the NDN node receives the Interest message, it will record the interface where the Interest message enters the node, and then forward it through the naming-based routing and forwarding protocol. Once the Interest message reaches a node that owns the requested data, a Data message is sent back, which carries the name and content of the data, and a signature of the producer key. This Data message reaches the consumer through the reverse path generated by the Interest message.

With the rapid development of computer technology, cloud computing has entered the stage of history in line with the requirements of the times. Virtual machine migration is one of the important technologies of virtualization and efficient allocation of resources in cloud computing technology. Virtual machine migration is divided into online migration and offline migration. Online migration has become the main research point of virtual machine migration because it can ensure uninterrupted migration process. Virtual machines are also necessary in the future network, because virtual machines are not only conducive to the efficient use of host resources, but also play an important role in the isolation of users. Virtual machine migration is beneficial to network performance optimization strategies in terms of load balancing, disaster backup, and user proximity. Therefore, online migration of virtual machines is also required.

In terms of future networks, there have been some studies on online migration of virtual machines, but there are still some problems, such as relatively long total migration time and downtime.

Contents of the invention

The purpose of the present invention is to provide a method for realizing online migration of virtual machines under NDN based on a two-way pipeline in order to overcome the above-mentioned defects in the prior art, research on the communication model of NDN and the implementation of online migration of virtual machines in the future network Research plays an important role in promoting.

The purpose of the present invention can be achieved through the following technical solutions:

A method for realizing online migration of a virtual machine based on a two-way pipeline under NDN, comprising the following steps:

(1) Namespace design steps in NDN: build NDN for data migration, data packets in NDN are divided into Interest and Data, define three namespaces for naming data packets:

The first name space is used to identify the data package in the migration process;

The second name space is used to identify the last data packet at the end of the migration;

The third name space, when the data packet is lost due to the large data packet during the data migration process, the data packet is divided into several, and the third name space is used for identification;

(2) Two-way pipeline communication step: The data requester and the data sender communicate data packets through a two-way pipeline, specifically: the data requester sends Interest to the data sender in the form of a pipeline, and the data sender generates the corresponding Data after receiving , and send Data to the data requester in the form of a pipeline, and the data requester generates a new Interest after receiving the returned Data. After the data packet transmission ends, the data migration ends;

The two-way pipeline communication steps include reverse order and packet loss processing. The reverse order processing is to set a buffer area for saving the data that arrives in advance or is generated in advance due to the reverse order respectively on the data requester and the data sender. Transfer mechanism to re-acquire Data. When the timeout is Q times, the Interest is divided into several small data blocks in the form of subcontracting to request the Data. The subcontracted data packets are named after the third namespace, and Q is the number of timeouts threshold;

(3) Performance testing steps: run an application prefixed with a location-independent name in a virtual machine, verify the onlineness of virtual machine migration by accessing the application, and use the NDN ping program to measure the downtime of the virtual machine.

The format of the first name space is /ndn/location/vm/migration/live/version/data/sequence, where /ndn is the root component shared by the name space in NDN, and /location indicates the device where the data sender is located Or the name of the gateway, /vm indicates that the name belongs to the name related to the virtual machine, /migration indicates that the name is the name used by the migration application, /live indicates that the name is online migration, /version indicates the version of the online migration namespace number, /data indicates that the name is the name that identifies the migrated data, and /sequence indicates the sequence number of the migrated data, which is used to uniquely identify the data blocks that are migrated online by different virtual machines.

The format of the second namespace is /ndn/location/vm/migration/live/version/data/end/last, where /end indicates that the migration data has ended, and /last indicates the last serial number of the migration data block, and The value of sequence is not greater than the value of last.

The format of the third namespace is /ndn/location/vm/migration/live/version/data/sequence/frag/nums/seq, where /frag indicates that the name is a subcontracted name, and the component of /nums Indicates that a data packet is divided into several, /seq indicates the sequence number of the sub-packet with the name.

The two-way pipeline communication data packet includes two phases: a start-up phase and a stable phase;

Start-up phase: the data requester initially sends 2N Interests, and the data sender generates and returns N data;

Stable stage: the data requester receives a Data and generates a new Interest at the same time;

After the startup phase, it enters the stable phase. During the stable phase, the transmission of Data and Interest constitutes two opposite pipelines, forming a data flow ring, where N=BD/L, and N is the maximum number of Data being transmitted in the network. B is the network bandwidth, D is the network delay, and L is the length of Data.

The length Len of the cache array in the cache area is determined by the maximum number N of data being transmitted in the network, the timeout threshold Q, the timeout time T and the network delay D.

The processing of the reverse order is specifically as follows: the first Data buffer is set in the data requester to save the Data that arrives in advance, and the second Data buffer is set in the data sender to save the Data that is generated in advance, and the data requester will The received Data with the correct sequence number is written to the virtual machine at the same time as the cached and early-arriving Data.

In the performance test step, the ping program using NDN sends Interest to the virtual machine to request a Data response every Pms. According to the number M of packet loss in the ping program during the shutdown process, the downtime of the online migration of the virtual machine is obtained. The value range of the downtime is [ (M-1)×P, (M+1)×P]ms, the error range is ±Pms, where P≥300.

Compared with the prior art, the present invention proposes the design of the NDN name, the communication model of the two-way pipeline, and the processing method for reverse sequence and packet loss, which has the following advantages:

1) The design of the name in NDN is a key issue. The present invention is based on the framework of NDN, designs the name space, and proposes name spaces in three cases, which are used to identify the process of migrating data, when the end of the migration, and Data packets when there are too many packet loss ensure the feasibility of virtual machine online migration under NDN, and have the security and convenience of NDN network communication.

2) Establish a two-way pipeline communication model, regard the network as a cache area, and Interest and Data form a ring to ensure that there is always data packet processing in the consumer and producer. Compared with the existing research on online migration of virtual machines under NDN, the speed of online migration is improved and the total migration time of online migration is reduced.

3) Aiming at the problems of reverse order and packet loss in the actual online migration process, set up a buffer area for saving the data that arrives in advance or is generated in advance due to the reverse order, so as to solve the reverse order. At the same time, the timeout retransmission mechanism is adopted when the number of packet loss is small. However, if packet loss still occurs after repeated overtime retransmissions, an Interest requesting a large data block is divided into several Interests requesting a small data block. From the perspective of reducing the size of the data block, the problem of excessive packet loss is solved and online The stability of migration and the reliability of data transmission.

4) Propose a method for evaluating the performance of the virtual machine online migration method of the present invention, run the application prefixed with a location-independent name in the virtual machine, wherein the location-independent name has good versatility, and can be obtained from different test terminals You can access the application of the virtual machine, which is convenient to verify the online migration of the virtual machine by accessing the application. At the same time, use the ping program of NDN to measure the downtime of the virtual machine, which can be used for comparative experiment verification in experiments, etc., in the laboratory The performance comparison between NDN and TCP/IP virtual machine online migration under ideal environment and real network environment can prove that TCP/IP cannot inherently support virtual machine online migration, but NDN can inherently support virtual machine online migration . At the same time, the total time of NDN is less than the total time of TCP/IP, indicating that the migration program under NDN is better than TCP/IP in terms of packet loss, delay, and reverse sequence processing.

5) The method of the present invention can realize the online migration of the virtual machine in both the local area network and the wide area network. The dynamic self-adaptation mechanism ensures that the network is smooth after the migration is completed.

Description of drawings

Fig. 1 is the schematic diagram of the communication model of two-way pipeline of the present invention;

Fig. 2 is a schematic diagram of a virtual machine online migration experiment test bed in an ideal environment;

FIG. 3 is a schematic diagram of a virtual machine online migration experiment test bed in a real environment.

In the figure: HOST_A is the source host, HOST_B is the destination host, and HOST_VM is the virtual machine to be migrated.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is carried out on the premise of the technical solution of the present invention, and detailed implementation and specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments.

A method for realizing online migration of a virtual machine based on a two-way pipeline under NDN includes the following steps:

(1) Name space design steps in NDN: build NDN for data migration, data packets in NDN are divided into Interest and Data, and names in NDN are independent of the NDN forwarding program (NFD) but a very important part, so the virtual machine During live migration, three namespaces are defined for naming packages:

The first name space is used to identify the data package in the migration process;

The second name space is used to identify the last data packet at the end of the migration;

The third name space, when the data packet is lost due to the large data packet during the data migration process, the data packet is divided into several, and then identified with the third name space; the specific settings of the components in each name space are as follows:

The format of the first namespace is /ndn/location/vm/migration/live/version/data/sequence, where /ndn is the root component shared by namespaces in NDN, and /location indicates the device or gateway where the data sender is located /vm indicates that the name belongs to the name related to the virtual machine, /migration indicates that the name is the name used by the migration application, /live indicates that the name is online migration, /version indicates the version number of the online migration name space, /data indicates that the name is the name that identifies the migration data, and /sequence indicates the sequence number of the migration data, which is used to uniquely identify the data blocks that are migrated online by different virtual machines.

The format of the second namespace is /ndn/location/vm/migration/live/version/data/end/last, where /end indicates that the migration data has ended, /last indicates the last serial number of the migration data block, and the sequence The value is not greater than the value of last.

The format of the third namespace is /ndn/location/vm/migration/live/version/data/sequence/frag/nums/seq, where /frag indicates that the name is a subcontracted name, and the component of /nums indicates a The data packet is divided into several, and /seq indicates the sequence number of the sub-packet with the name.

(2) Two-way pipeline communication steps: The data requester (consumer) and the data sender (producer) communicate data packets through a two-way pipeline. The two-way pipeline communication means: the data requester continuously sends Interest to the data sender in the form of a pipeline , the data sender generates the corresponding Data after receiving it, and continuously sends Data to the data requester in the form of a pipeline, and the data requester generates a new Interest after receiving the returned Data. In the two-way pipeline communication, the data in the process of data migration The package is named in the first name space, and the data migration ends when the transmission of the data package named in the second name space ends.

The two-way pipeline communication packet includes two phases: startup phase and stabilization phase;

Start-up phase: the data requester initially sends 2N Interests, and the data sender generates and returns N data;

Stable stage: The data requester receives a piece of data and generates a new interest at the same time. If and only when the consumer continuously sends interest and the producer continuously generates data, the online migration of the virtual machine can be transmitted at a faster speed.

After the migration starts, it enters the stable stage from the startup stage. In the stable stage, the transmission of Data and Interest constitutes two opposite pipelines, forming a data flow ring. This bidirectional pipeline model enables the migration data to be continuously sent from the producer to the consumer. Among them, N=BD/L, N is the maximum number of Data being transmitted in the network, B is the network bandwidth, D is the network delay, and L is the length of Data. The communication model of the two-way pipeline is shown in Figure 1. The dotted line indicates the steps currently in progress, and the solid line indicates the completed steps, which can be divided into the following steps:

Step S1: The consumer initially sends 2N Interests;

Step S2: Producer generates x data continuously after receiving Interest, x<N;

Step S3: Producer generates and returns N data, consumer receives Data and generates new Interest;

Step S4: Repeat steps S2 and S3, transition from the start-up phase to the stable phase, the consumer receives a Data and generates a new Interest at the same time, X represents the sequence number of the Data currently processed by the producer.

The two-way pipeline communication steps include reverse sequence and packet loss processing. The reverse sequence processing is to set a buffer area for saving the data that arrives in advance or is generated in advance due to the reverse sequence, respectively, on the data requester and the data sender. Specifically: the first Data buffer is set in the data requester to save the Data that arrives in advance due to the reverse order, and the second Data buffer is set in the data sender to save the Data that is generated in advance due to the reverse order, and the data requester Write the received Data with the correct serial number together with the cached early-arriving Data to the virtual machine at the same time.

The processing of packet loss is to use the timeout retransmission mechanism to reacquire the Data. When the timeout is Q times, the Interest is divided into several small data blocks to request the Data, and the corresponding Data will be correspondingly divided into several Data of small data blocks are returned, and the subpackaged data packets are named after the third name space, and Q is the timeout threshold.

The length Len of the cache array in the cache area is determined by the maximum number N of data being transmitted in the network, the timeout threshold Q, the timeout time T (the default value of the timeout retransmission mechanism), and the network delay D. In the extreme case, when the data with the serial number X has not been received, but the data after the serial number X can always be received, at this time, it must wait for the timeout Q times, and the data corresponding to X is divided into several small data for transmission. The consumer can retrieve the Data. Therefore, Len must be greater than which is

(3) Performance testing steps: NDN uses names as identifiers, which have nothing to do with location. Therefore, when a virtual machine is migrated to a new location, using a location-independent name as a prefix can ensure that communication can be naturally restored after the migration . Run an application prefixed with a location-independent name (for example, using a broadcast name prefix as a common name prefix) in the virtual machine, verify the onlineness of the virtual machine migration by accessing the application, and use the NDN ping program every Pms sends Interest to the virtual machine to request a Data response, and according to the number M of packet loss in the ping program during the shutdown process, the downtime of the online migration of the virtual machine is obtained. The value range of the downtime is [(M-1)×P, (M+1 )×P]ms, the error range is ±Pms, wherein, P≥300, in the experimental test, the three cases of P=200ms, 250ms, and 300ms were tested respectively, and it was found that when P=200ms and 250ms, the packet sending rate was too high It is too fast to measure M, and when P=300ms, the measured M can more accurately reflect the packet loss situation. Generally, the smaller the P, the better, but considering the actual test results, so P can be selected to be greater than or equal to 300. At the same time, it is the best choice when P=300ms.

Experiment of the present invention is divided into two parts: the online migration of virtual machine under ideal environment (local area network) and the online migration of virtual machine under real network environment (wide area network), Fig. 2 is the experimental test bed of online migration of virtual machine under ideal environment, Fig. 3 Experimental test bed for online migration of virtual machines in a real environment.

The specific implementation process of the first part of the ideal environment is as follows:

Step 1: Run the NDN forwarding routine NFD of the source host host HOST_A and the destination host host HOST_B. The specific command is: nfd-start. Register FIB entries on HOST_B, the specific command is: nfdc register/ndn/cn/edu/tongji/vm udp4://10.0.2.1;

Step 2: Start the virtual machine HOST_VM on the source host host HOST_A, the startup parameters are: -m 640-smp 1-drive file=/var/lib/libvirt/images/ubuntu.img,if=virtio,format=raw-netnic ,vlan=0,macaddr=52:54:00:6d:82:f9-net tap,vlan=0,ifname=tap0,script=no, where, the size of /var/lib/libvirt/images/ubuntu.img is 4G;

Step 3: Start the service ndnpingserver in the virtual machine that responds to the echo request in HOST_VM. The specific command is: ndnpingserver/ndn/broadcast/tongji/hostVM. Start the NDN ping client on HOST_A, the specific command is: ndnping–i 300/ndn/broadcast/tongji/hostVM.

Step 4: Start the receiving process of the virtual machine HOST_VM online migration on the destination host HOST_B. The starting method is to add the exec method of QEMU-KVM to receive the migration data after the source host host HOST_A starts the virtual machine startup parameters in step 2:- Incoming testconsumer, where testconsumer is the migration data receiving process.

Step 5: Enter the migration startup command in the QEMU control window of the source host host HOST_A, the command is: migrate–b exec:testproducer, where the parameter indicates that the migration method is block migration, and testproducer is the process name for sending the migration data.

Step 6: After the migration is complete, check whether the Ping client used for performance testing of the source host host HOST_A can still continue to run, and check the time difference between the response packet received and the request packet sent during the shutdown process.

The specific implementation process of the second part of the real environment is the same except that step 1 is different from the ideal environment above, and the rest of the steps are the same. In the real environment, the virtual machine between Tongji University and Wayne State University (WSU) is online. Taking migration as an example, step 1 of the specific implementation process in the real environment is as follows:

Step 1: Run the NDN forwarding routine NFD of the source host host HOST_A and the destination host host HOST_B. The specific command is: nfd-start. Register the FIB entry on HOST_A, the specific command is: nfdc register/ndn udp4://10.0.2.2. Register the FIB entry on HOST_B, the specific command is: nfdc register/ndn udp4://192.168.0.1. Register the FIB entry on the Tongji testbed node. The specific command is: nfdc register/ndn/cn/edu/tongji/vm/migration udp4://10.0.2.1. To register the FIB entry on the WSU gateway, the specific command is: nfdc register/ndn/cn/edu/tongji udp4://202.120.188.176.

Simultaneously test the performance of the virtual machine online migration under the laboratory ideal environment and the real network environment (identical with the experimental environment of the above-mentioned inventive method) TCP/IP, wherein the virtual machine under the laboratory ideal environment TCP/IP is online UDP communication technology is used for migration, and TCP communication technology is used for online migration of virtual machines under TCP/IP in the real network environment. Finally, the total time and downtime of online migration of virtual machines under NDN and TCP/IP under ideal environment and real environment are obtained Time Downtime value comparison table, as shown in Table 1 and Table 2.

Table 1 Total time and Downtime of online migration of virtual machines under NDN and TCP/IP in an ideal environment

Table 2 Total time and Downtime of virtual machine online migration under NDN and TCP/IP in real environment

Network Architecture total time Downtime NDN 7min21sec 1.5sec TCP/IP 10min10sec NP

Note: NP means no measurement result.

It can be found from Table 1 that the total time of virtual machine online migration under NDN is close to the total time of migration under TCP/IP, and the downtime of both is the same. Table 2 shows that the online migration of virtual machines cannot be inherently supported under TCP/IP, but NDN can inherently support online migration of virtual machines. At the same time, the total time of NDN is less than the total time of TCP/IP. Experiments show that the migration program under NDN is better than TCP/IP in terms of packet loss, delay, and reverse order processing. In summary, the present invention completes the virtual machine online migration and its performance measurement under the future network architecture NDN, and verifies the feasibility and advantages of the present invention through comparative experiments. It is an important exploration for online migration in data networks.

Claims (8)

1. a kind of realize the method that virtual machine migrates online under NDN based on two-way pipe method, it is characterised in that including following Step：

(1) name space design procedure in NDN：Build NDN and carry out Data Migration, in NDN data packet be divided into Interest and Data, definition are used for three name spaces for naming data packet：

First name space, for identifying the data packet in transition process；

Second name space, last data packet terminated for identifying migration；

Third word space, in data migration process because data packet is excessive and during packet loss, after which is divided into several, use Third word space is identified；

(2) two-way pipeline communication step：By two-way pipeline communication data packet between request of data side and data sender, specifically For：Request of data side sends Interest in a manner of pipeline to data sender, and data sender produces corresponding after receiving Data, and Data is sent to request of data side in a manner of pipeline, request of data side produces newly after receiving the Data of return Interest, the data packet in data migration process is named with the first name space, when what is named with the second name space After the data packet end of transmission, Data Migration terminates；

Two-way pipeline communication step includes backward and packet loss is handled, and the processing of backward is in request of data side and data sender point Not She Zhi one be used to preserve because backward advances to the buffer area of the Data for reaching or producing in advance, the processing of packet loss is using super When retransmission mechanism reacquire Data, when Q times overtime after, by the way of subpackage Interest is divided into several small datas The Interest of block asks the Data, and the data packet after subpackage is named with third word space, and Q is overtime time threshold value；

(3) performance test step：Application of the operation using the name unrelated with position as prefix in virtual machine, should be answered by accessing With verifying virtual machines migration in downtime that is linear, while using the ping utility measurement virtual machine of NDN.

2. according to claim 1 realize the method that virtual machine migrates online under NDN based on two-way pipe method, it is special Sign is that the form of first name space is /ndn/location/vm/migration/live/version/data/ Sequence, wherein ,/ndn is the root components common to name space in NDN, and/location is represented where data sender Equipment or gateway name ,/vm shows that the name belongs to and shows the name with the relevant name of virtual machine ,/migration It is that used name is applied in migration ,/live shows that the name is to migrate online, and/version shows that the online migration name is empty Between version number ,/data shows that the name is to identify the name of migrating data, and/sequence shows the sequence number of migrating data, uses In the data block that the different virtual machine of unique mark migrates online.

3. according to claim 2 realize the method that virtual machine migrates online under NDN based on two-way pipe method, it is special Sign is that the form of second name space is /ndn/location/vm/migration/live/version/data/ End/last, wherein ,/end shows that migrating data is over, and/last identifies last sequence number of migrating data block, and The numerical value of sequence is not more than the numerical value of last.

4. according to claim 2 realize the method that virtual machine migrates online under NDN based on two-way pipe method, it is special Sign is that the form of the third word space is /ndn/location/vm/migration/live/version/data/ Sequence/frag/nums/seq, wherein ,/frag shows that the name is the name of a subpackage, and the component of/nums shows one A data coating divide into several, and/seq shows the sequence number of the name subpackage.

5. according to claim 1 realize the method that virtual machine migrates online under NDN based on two-way pipe method, it is special Sign is that the two-way pipeline communication data packet includes two stages：Startup stage and stabilization sub stage；

Startup stage：Request of data side sends 2N Interest, and data sender produces and returns to N number of data；

Stabilization sub stage：Request of data side receives a Data and produces a new Interest at the same time；

Entering the stabilization sub stage after startup stage, during the stabilization sub stage, the transmission of Data and Interest form two opposite pipelines, A data flow ring is formed, wherein, N=BD/L, N are the maximum number of Data transmitted in network, and B is network bandwidth, D It is network delay, L is the length of Data.

6. according to claim 1 realize the method that virtual machine migrates online under NDN based on two-way pipe method, it is special Sign is, maximum number N by the Data that is being transmitted in network of the length Len of array, time-out time are cached in the buffer area Number threshold value Q, time-out time T and network delay D are determined.

7. according to claim 1 realize the method that virtual machine migrates online under NDN based on two-way pipe method, it is special Sign is that the processing of the backward is specially：First Data buffering areas are set in request of data side, advance to what is reached for preserving Data, the 2nd Data buffering areas are set in data sender, and for preserving the Data produced in advance, request of data side will be received The Data of correct sequence number is written to virtual machine at the same time together with the Data that advanceing to of caching thereafter reaches.

8. according to claim 1 realize the method that virtual machine migrates online under NDN based on two-way pipe method, it is special Sign is, in performance test step, sends Interest every Pms using the ping utility of NDN and is rung to virtual machine request Data Should, according to number of dropped packets M in ping utility in stopping process, obtain the downtime that virtual machine migrates online, the number of downtime Value scope is [(M-1) × P, (M+1) × P] ms, and error range is ± Pms, wherein, P >=300.