JP2000138713A - Cluster system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the takeover of an IP address without needing client application remodeling or further name service server setting by mounting a filter driver. SOLUTION: When an Ethernet (registered trademark) trailer which is transmitted from a client computer 10C via a network 11 is received by the network interface 108 of a server computer 10A and the matching of destination MAC addresses is detected, an IP(Internet protocol) trailer in the Ethernet trailer is transferred from an interface layer 101 to a filter driver 100. When a flag 100a capable of setting state switching is turned on, the filter driver 100 does not filter the IP trailer but filters the IP trailer according to whether or not a destination IP address is an IPS, when it is turned off and annuls the IP trailer as long as it is an IPS.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cluster system in which services are taken over between server computers, and more particularly to a cluster system having a driver (filter driver) for filtering a network trailer in received data. Cluster system with

[0002]

2. Description of the Related Art Conventionally, a plurality of server computers (nodes) are connected via a network, and even if a failure occurs in a certain server computer, the service stopped by the failure is taken over by another server computer, so that the entire system is obtained. Various cluster systems that can maintain availability have been developed.

In this type of cluster system, takeover of an IP (Internet Protocol) address as a network address is required to take over services between computers. Therefore, for example, if a cluster system in which two server computers A and B are connected by a network is described, the computers A and B have unique IP addresses IPA and IP, respectively.
In addition to B (not limited to one type), a specific IP address IPS to be taken over is set.

[0004]

However, in the conventional cluster system, in order to take over the IP address,
It was not possible to dynamically set or release the IP address. Also, a logical IP address cannot be dynamically activated or deactivated,
There has been a problem that an OS (operating system) cannot take over an IP address.

Therefore, conventionally, in order to realize takeover of an IP address, an application (client application) operating on a client computer is modified to introduce a special mechanism for switching a communication partner, or a name service (host name and IP address) is required. It is necessary to set up a server (name service server) that manages the service that associates the address with the address, and switch the correspondence between the host name and the IP address in the name service.

In order to balance the load of the entire system by distributing the load in a conventional cluster system, it is realized by switching a server computer to be provided with a service by a client application, or a layer 4 is used. It was implemented using a special hardware mechanism called a switch. That is, in order to perform load distribution in the conventional class system, a dedicated application (application program) or a dedicated hardware mechanism is required.

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to implement a filter driver even in a server computer having an OS on which conventional network address takeover has been impossible.
An object of the present invention is to provide a cluster system that can realize takeover of a network address without remodeling a client application and setting a name service server.

Another object of the present invention is to implement a filter driver in a server computer so that load distribution can be performed in the same manner as when a layer 4 switch is used without using a dedicated application or a dedicated hardware mechanism. It is to provide a cluster system that can be realized.

[0009]

SUMMARY OF THE INVENTION The present invention provides a cluster system in which a service is taken over between server computers by communication using communication data including a network trailer in which a specific network address to be taken over is set as a destination network address. In each of the server computers, a flag information holding unit that holds flag information that can be arbitrarily set to be switched to one of the first and second states, and, when receiving communication data, refer to the flag information. In the case of the first state, the filtering of the network trailer in the communication data is not performed.
In the case of the state, filtering of the network trailer is performed depending on whether the destination network address in the network trailer is the specific network address, and only when the destination network address is the specific network address,
And a filter driver for discarding the network trailer.

In such a configuration, the flag information held in each server computer to which a specific network address (taken over) is set indicates validity / invalidity of the specific network address in the computer.
Therefore, in each of the above-mentioned computers, the state of the flag information (the first flag information) is dynamically determined by a user operation or communication between the computers using a predetermined command (flag operation command).
Or the second state), and the filter driver determines to discard the network trailer based on the state of the flag information and the destination network address of the received data in the network trailer.
Takeover of an important network address (for example, an IP address) in a cluster system can be realized.

The present invention also provides a cluster system having a plurality of server computers on which a plurality of specific network addresses to be taken over are set, each of the server computers being provided corresponding to each of the plurality of specific network addresses. Flag information holding means for holding flag information that can be set to be arbitrarily and independently switched to one of the first and second states; and In the case of the state, the filtering of the network trailer in the communication data is not performed. In the other cases, the destination network address in the network trailer is set to the specific network address corresponding to the flag information in the second state. A filter that discards the network trailer if it matches one Characterized in that it also comprises a filter driver to perform grayed.

In such a configuration, in each of the server computers, the state of a plurality of pieces of flag information (first or second state) is dynamically changed by a user operation or communication between the computers using a predetermined command. ) Is switched, and the filter driver decides to discard the network trailer based on the status of the plurality of flag information and the destination network address in the network trailer of the received data. A plurality of takeovers can be realized.

Further, the present invention receives communication data from a client computer including a network trailer in which a specific network address designating a server computer which provides a service is set as a destination network address, and receives the communication data from a plurality of server computers. In a cluster system in which one of the server computers to which a specific network address is set communicates with the client computer, each of the server computers is activated when receiving communication data having the specific network address as a destination network address, and Based on the information on the source computer in the data, the own computer determines whether or not the service should be provided, and sets a corresponding flag information. To the destination physical address inside The network trailer in the communication data is taken out of the relationship, the destination network address is checked, and the destination network address matches the specific network address, and the determination means indicates that the computer should not provide the service. A filter driver that discards the network trailer only when the flag information is set, and otherwise passes the network trailer to the network layer.

In such a configuration, even if a plurality of server computers to which a specific network address is set, that is, a plurality of server computers designated as computers providing a service, exist simultaneously, the information about the transmission source computer in the communication data. (That is, information about the client computer that has requested the service),
Only one can communicate with the requesting client computer as a server computer that actually provides the service, and it is possible to achieve load distribution.

Here, as the information on the source computer in the communication data, any one of the information of the source network address, the source physical address, and the source port number in the communication data is used. If information combining at least two of the source physical address and the source port number is used, load distribution can be easily realized. In this case, when the state of the flag information is determined based on whether or not a predetermined portion of the information matches a predetermined value, that is, when it is determined whether the host computer should actually provide a service, Good. If the difference in the capability of each server computer is reflected in the determination of the state of the flag information, effective load distribution can be realized.

It is preferable that the determination means of each server computer to which a specific network address is set determine the only server computer that provides a service by communicating with each other for each communication.

In this case, a server computer that provides a service can be dynamically determined for each communication, so that more effective load distribution can be realized.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment] FIG. 1 is a block diagram showing a configuration of a cluster system according to a first embodiment of the present invention.

In FIG. 1, a plurality of server computers, for example, server computers 10A and 10B and a client computer 10C are connected by a network 11. Server computers 10A and 10B and client computer 10
C is TCP / IP (transmission
ntrol protocol / internetpr
(autocol) program.

The server computers 10A and 10B have IP addresses IPA and IPB (as network addresses) unique to the server computers 10A and 10B, respectively.
(Not limited to one type) and MAC addresses MACA and MACB (as physical addresses) are set, and a common takeover IP address IPS is set for the server computers 10A and 10B.

A filter driver 100 directly related to the present invention is mounted on the server computer 10A. The filter driver 100 includes an interface layer 10 applied for communication between computers via a network 11.
1, network layer 102, transport layer 103,
And the application layer 104 between the interface layer 101 and the network layer 102. Interface layer 101, network layer 102,
The transport layer 103 is realized by the communication driver 105.

The filter driver 100 performs filtering of a destination IP address, and has a flag 100a (F) for designating ON / OFF of the IP address IPS. This flag 10
0a is dynamically turned on / off when the flag operation mechanism 106 realized by the command execution function of the server computer 10A executes a predetermined flag operation command 107.

In this embodiment, the filter driver 10
0 indicates that if the flag 100a is on, the IP trailer (network trailer) 23 (see FIG. 2) sent from the interface
02. When the flag 100a is off, the filter driver 100 sets the destination IP address 24 in the IP trailer 23 (see FIG. 2).
The IP trailer 23 is configured to be discarded or passed to the network layer 102 depending on whether or not the IP trailer matches the IPS.

A network interface 108 for interfacing with the network 11 is provided before the interface layer 101. This network interface 108 constitutes a physical layer.

The above configuration is the same for server computers other than the server computer 10A, for example, the server computer 10B. Therefore, taking the flag 100a of the filter driver 100 as an example, the server computer 10B sets the flag 100a to o according to the flag operation command 107.
n / off operation is possible. This operation may be performed by communicating with each other between the server computers 10A and 10B. However, in FIG. 1, the configuration of the server computer 10B is omitted.

FIG. 2 shows an Ethernet (Eth) as communication data (communication packet) transferred through the network 11.
1 shows a schematic format of an ernet® trailer 20.

As shown in FIG. 1, the Ethernet trailer 20 has a destination MAC (MediaAccess Con).
(Troll) address 21 and an IP trailer 23. The IP trailer 23 has a header (IP header) 26 including a destination IP address 24 and a source IP address 25.
have.

Next, the operation of the system shown in FIG. 1 will be described with reference to a flowchart shown in FIG. 3, taking a takeover of an IP address when taking over a service from the server computer 10B to the server computer 10A as an example.

First, an Ethernet trailer (communication packet) 20 whose destination IP address 24 of the IP trailer 23 is IPS, that is, an Ethernet trailer 20 including the IP trailer 23 addressed to the IPS is transmitted from the client computer 10C onto the network 11. Shall be.
The Ethernet trailer 20 transmitted from the client computer 10C onto the network 11 is guided to each computer connected to the network 11 and received by the network interface of the computer. For example, the Ethernet trailer 20 from the client computer 10C is guided to the server computer 10A through the path indicated by reference numeral 12 in FIG.
A is received by the network interface 108 of A.

The data is received by the network interface 108 of the server computer 10A (the client computer 10A).
The Ethernet trailer 20 (from C) is passed to the interface layer 101 of the server computer 10A.

Interface layer 1 of server computer 10A
01, the destination MAC address 21 in the header section 22 of the Ethernet trailer 20 is checked (Step S).
1).

As a result of the MAC address check in step S1, if the destination MAC address 21 matches the MACA (step S2), the interface layer 101 determines that the Ethernet trailer 20 is addressed to itself, and The IP trailer 23 is taken out from the server and passed to the filter driver 100 (step S3). On the other hand, if the destination MAC address 21
If it does not match A (step S2), the interface layer 101 determines that the Ethernet trailer 20 is not addressed to itself, and
Is discarded (step S4).

Upon receiving the IP trailer 23 from the interface layer 101, the filter driver 100 refers to the state of the flag (F) 100a and determines whether or not the flag 100a is on (step S5).

If the flag 100a is on, that is, if the flag 100a is turned on by the operation of the flag operating mechanism 106 in the server computer 10A in accordance with the flag operation command 107, the filter driver 100 performs special filtering. The operation is not performed, and the IP trailer 23 passed from the interface layer 101 is passed to the network layer 102 as it is (step S6).

Therefore, when the destination IP address 24 matching the IPS is set in the IP trailer 23 as in the present embodiment, the IP trailer 23 is transferred to the network layer 102 in the same server computer 10A. Thus, takeover of the IP address in the server computer 10A becomes possible.

On the other hand, if the flag 100a is in the off state, that is, if the flag 100a is turned off by the operation of the flag operation mechanism 106 in the server computer 10A according to the flag operation command 107, the filter driver 100 The filtering operation described below is performed.

First, the filter driver 100 checks the destination IP address 24 in the IP trailer 23 passed from the interface layer 101, and determines whether or not the destination IP address 24 matches the IPS (step S).
7, S8).

If the destination IP address 24 in the IP trailer 23 matches the IPS, that is, if it is the IP trailer 23 addressed to the IPS, the flag 100a is set to o.
In the state of ff, since the own computer 10A is not a target of the takeover of the IP address IPS, the filter driver 100 discards the IP trailer 23 (step S9). Therefore, it is possible to prevent the IP address takeover from being performed in the server computer 10A in which the flag 100a is in the off state.

On the other hand, the destination I in the IP trailer 23
If the P address 24 does not match the IPS,
If it is not the IP trailer 23 addressed to the PS, it is not related to the takeover of the IP address IPS.
00a is off, the filter driver 1
00 passes the IP trailer 23 to the network layer 102 (step S6).

[Second Embodiment] FIG. 4 is a block diagram showing the configuration of a cluster system according to a second embodiment of the present invention, and the same parts as those in FIG. 1 are denoted by the same reference numerals.

In FIG. 4, the server computer 10 shown in FIG.
Server computers 40A and 40B corresponding to A and 10B and a client computer 40C corresponding to the client computer 10C are connected by a network 11. Each of the server computers 40A and 40B has an IP address unique to the server computer 40A and 40B.
A and IPB (not limited to one type) are set, and a plurality of IP addresses for takeover common to the server computers 10A and 10B, for example, two IP addresses IPS1 and IPS2 are set.

A filter driver 400 located between the interface layer 101 and the network layer 102 is mounted on the server computer 40A. The filter driver 400 filters the destination IP address, and turns on / off the IP addresses IPS1 and IPS2.
flags 400a (F1), 400 for designating ff
b (F2). This flag 400a (F
1) and 400b (F2) are dynamically and independently turned on / off by the flag operation mechanism 106 executing a predetermined flag operation command 407. Filter driver 40
If the flag (F1) and the flag 400b (F2) are all on, 0 indicates that the IP trailer 23 passed from the interface layer 101 is passed to the network layer 102 as it is. In addition, the filter driver 400 sets the flags (F1), 400
If at least one of b (F2) is off, IP
The destination IP address 24 in the trailer 23 is
IP address IP corresponding to the state flag (Fi)
The IP trailer 23 is discarded or the network layer 102
Let through.

The above configuration is the same for server computers other than the server computer 40A, for example, the server computer 40B.

Next, the operation of the system shown in FIG. 4 will be described with reference to a flowchart shown in FIG. 5, taking an example of takeover of an IP address when a service is taken over from the server computer 40B to the server computer 40A.

First, it is assumed that the Ethernet trailer 20 whose destination IP address 24 of the IP trailer 23 is IPS1 or IPS2 is transmitted from the client computer 40C onto the network 11. The Ethernet trailer 20 is guided to, for example, the server computer 40A via a path indicated by reference numeral 42 in FIG. 4, and is received by the network interface 108 of the server computer 40A.

The data is received by the network interface 108 of the server computer 40A (the client computer 40A).
The Ethernet trailer 20 (from C) is passed to the interface layer 101 of the server computer 40A. In the interface layer 101, steps S11 to S1 corresponding to steps S1 to S3 in the first embodiment are performed.
3, or steps S11, S12, and S14 corresponding to steps S1, S2, and S4 are performed.

If steps S11 to S13 have been executed, the filter driver 400 receives the IP trailer 23 in the Ethernet trailer 20 from the interface layer 101. In this case, the filter driver 400 outputs the flags 400a (F1) and 400b (F
With reference to the state of 2), the flags F1 and F2 are all on.
It is determined whether it is in the state (step S15).

If the flags F1 and F2 are all on, the filter driver 400 does not perform a special filtering operation, and passes the IP trailer 23 received from the interface layer 101 as it is to the network layer 10
2 (step S16).

Therefore, when the destination IP address 24 corresponding to IPS1 or IPS2 is set in the IP trailer 23, the IP trailer 23 is transferred to the network layer 102 in the same server computer 40A, and the server The takeover of the IP address in the computer 40A becomes possible.

On the other hand, if at least one of the flags F1 and F2 is in the off state, the filter driver 400
Performs the filtering operation described below.

First, the filter driver 400 detects the flag Fi (i is at least one of 0 and 1) in the off state (step S17). Next, the filter driver 400 receives the I
The destination IP address 24 in the P trailer 23 is checked, and it is determined whether or not the destination IP address 24 matches the IP address IPSi corresponding to the flag Fi detected in step S17 (steps S18, S19).

If the destination IP address 24 in the IP trailer 23 matches the IPSi,
If the destination is the IP trailer 23, the flag Fi is set to o.
In the state of ff, the own computer 10A receives the IP address IPSi
The filter driver 400 discards the IP trailer 23 because it is not the target of takeover (step S20). Therefore, the takeover of the IP address IPSi can be prevented from being performed in the server computer 40A in which the flag Fi is in the off state.

On the other hand, the destination I in the IP trailer 23
If the P address 24 does not match the IPSi, that is, if it is not the IP trailer 23 destined for the IPSi, the filter driver 400 does not affect the takeover of the IP address IPSi even if the flag Fi is off. Trailer 23 to network layer 102
(Step S16).

[Third Embodiment] FIG. 6 is a block diagram showing a configuration of a cluster system according to a third embodiment of the present invention, and the same parts as those in FIG. 1 are denoted by the same reference numerals.

In FIG. 6, for example, the server computer 60
A, 60B and the client computer 60C are connected by a network 11. Server computer 60A,
60B executes a TCP / IP server program, and client server computer 60C executes a TCP / IP client program.

Each of the server computers 60A and 60B has an IP address IPA and IPB (not limited to one type) unique to the server computers 60A and 60B, and a MAC.
Addresses MACA and MACB are set, and an IP address IPS (indicating a server computer) that provides a common service to the server computers 60A and 60B is set.

A filter driver 600 is mounted on each of the server computers 60A and 60B. This filter driver 600 is located between the network interface 108 and the network layer 102. In the present embodiment, the filter driver 600 has the function of the interface layer. For this reason, the server computers 60A, 60
In B, unlike the first and second embodiments, there is no independent interface layer. Therefore, in the present embodiment, the server computers 60A, 60A
The configuration of the Ethernet trailer 20 received by the network interface 108 of B is passed to the filter driver 600 as it is.

The first feature of the filter driver 600 is as follows.
This is different from a normal interface layer (for example, the interface layer 101 in FIG. 1) in that the destination MAC address is not checked while having the function of the interface layer.

The second feature of the filter driver 600 is as follows.
The destination IP address included in the IP trailer 23 in the Ethernet trailer 20 received by the network interface 108 is checked, and if “off” is returned by the IPS and from the determination device 601 described later, the IP The configuration is such that the trailer 23 is discarded, and otherwise the IP trailer 23 is passed to the network layer 102.

The server computers 60A and 60B are also provided with a judgment device 601. This server computer 60
A, 60B determines the destination I included in the IP trailer 23 in the reception Ethernet trailer 20.
When the P address is IPS, it is started by the filter driver 600, and based on the transmission source IP address 25 in the IP trailer 23, "on" or "of" indicating whether or not the own server computers 60A and 60B should provide a service.
The flag information “f” is returned to the filter driver 600.

The network layer 102 and the transport layer 103 which is an upper layer of the network layer 102
Is realized by the communication driver 605.

Next, the operation of the system shown in FIG. 6 will be described by taking, as an example, the case where the Ethernet trailer 20 addressed to the IPS is transmitted from the client computer 60C onto the network 11.
This will be described with reference to the flowcharts of FIGS.

First, the Ethernet trailer (communication packet) 20 whose destination IP address 24 of the IP trailer 23 is IPS, that is, the Ethernet trailer 20 including the IP trailer 23 addressed to the IPS is transmitted from the client computer 60C onto the network 11. Shall be.
The Ethernet trailer 20 transmitted from the client computer 60C onto the network 11 is guided to each computer connected to the network 11, and received by the network interface of the computer. For example, the Ethernet trailer 20 from the client computer 60C is guided to the server computers 60A and 60B via a path indicated by reference numeral 62 in FIG. 6, and the network interface 10 of the server computers 60A and 60B is connected.
8 is received.

The Ethernet trailer 20 (from the client computer 60C) received by the network interface 108 of the server computers 60A and 60B is passed to the filter driver 600 as it is (step S2).
1).

The filter drivers 600 of the server computers 60A and 60B receive the received Ethernet trailer 2
0 of the destination MAC address 21 in the header portion 22 (different from the normal interface layer), and the destination MAC address 21
A, regardless of whether it matches MACB), the IP trailer 23 is taken out from the Ethernet trailer 20 (step S22).

Next, each of the filter drivers 600 of the server computers 60A and 60B checks the destination IP address 24 in the extracted IP trailer 23 and determines whether or not the destination IP address 24 matches the IPS (step). S23, S24).

If the destination IP address 24 in the IP trailer 23 does not match the IPS, that is, if the destination IP address 24 is not the IP trailer 23 addressed to the IPS, the filter driver 600 stores the IP trailer 23 in the network layer 102.
To the processing in the network layer 102 (step S6).

On the other hand, as in the present embodiment, if the destination IP address 24 in the IP trailer 23 matches the IPS, that is, if the IP trailer 23 is addressed to the IPS, the filter driver 600 sets the IP trailer 23 to It passes to the judgment device 601 of the same server computer 60A, 60B, and waits for the judgment result from the judgment device 601 (step S26).

Each of the judging devices 601 of the server computers 60A and 60B checks the source IP address 25 in the IP trailer 23 passed from the filter driver 600 (steps S31A and 31B), and finds that the IP address is an odd address (odd). ) Or even addresses (even
n) is determined (step S32A,
32B). This determination is made, for example, by checking whether the least significant bit of the IP address is “1” or “0”.

When the transmission source IP address 25 is an odd address, the judgment device 601 of the server computer 60A sets “on”
Of the flag information of the server computer 60B
Indicates the flag information of “off”,
The determination result is returned to the filter driver 600 of A, 60B (steps S33A, 33B).

On the other hand, when the transmission source IP address 25 is an even address, the judging device 601 of the server computer 60A sends the “off” flag information to the server computer 60A.
The determination device 601 of B returns the flag information of “on” as the determination result to the filter drivers 600 of the own computers 60A and 60B (steps S34A and 34B).

When each of the filter drivers 600 of the server computers 60A and 60B returns the flag information as the determination result from the determination device 601, the flag information is turned on / off.
ff is checked (step S27). If the flag information (judgment result) is “on”, the filter driver 600 passes the IP trailer 23 to the network layer 102 of the own computer (Step S25). On the other hand, if the flag information (determination result) is “off”, the filter driver 600 discards the IP trailer 23 (Step S28).

As described above, if the source IP address 25 included in the IP trailer 23 of the Ethernet trailer 20 from the client computer 60C, that is, the IP address set in the client computer 60C is an odd address, the server Judgment device 6 of computer 60A
01 is “on”, and the determination result of the determination device 601 of the server computer 60B is “off”, so that the IP trailer 2 (from the client computer 60C)
3 is processed by the server computer 60A, and communication is performed between the client computer 60C and the server computer 60A.

On the contrary, the client computer 60C
If the source IP address 25 included in the IP trailer 23 of the Ethernet trailer 20 is an even address, the determination result of the determination device 601 of the server computer 60A is “off”, and the determination device 601 of the server computer 60B. Is "on", the IP trailer 23 (from the client computer 60C) is processed by the server computer 60B, and the client computer 60
Communication is performed between C and the server computer 60B.

As described above, the server computers 60A and 60A
B, the IP trailer 23 (in the Ethernet trailer 20) addressed to the IPS from the client computer 60C is processed by only one of the server computers. Communication is performed only with the computer 60C. That is, only one of the server computers 60A and 60B is the client computer 60C of the request source.
To provide services.

Therefore, when there are a plurality of client computers 60C and the IP addresses set in each of the client computers 60C are almost the same as the even addresses and the odd addresses, half of all the client computers 60C receive the service from the server computer 60A. After receiving the service, the other half can receive the service from the server computer 60B, and the load distribution (load balancing) is achieved.

If the number of server computers is three or more, and the number is N, the i-th (i = 1 to N) server computer has an Ethernet trailer 2 addressed to the IPS.
When the source IP address 25 of 0 is N · n + (i−1) (where n = 0, 1, 2,...), “On” is returned from the determination device 601 to the filter driver 600. , Can cope.

When the capacity of each server computer is different, more efficient load distribution can be realized by taking the capacity into account. For example, in the case of two server computers 60A and 60B as in the system of FIG. 6, assuming that the capacity ratio between the server computers 60A and 60B is 3: 1, the server computer 60B has an IP address of 4 Only when the Ethernet trailer 20 addressed to the IPS is received from the client computer which is a multiple (that is, the lower 2 bits of the IP address is “00”), the server computer 60
In A, the Ethernet trailer 20 addressed to the IPS from the client computer whose IP address is not a multiple of 4
, The determination device 601 may return “on” to the filter driver 600 only when the filter device 600 receives the “.

In the above embodiment, when there are a plurality of server computers to which a service is provided (indicating a server computer) and an IP address IPS is set, it is determined which of the server computers provides the service by the transmission source. (Requesting Source) The case where the determination is made based on the IP address (source IP address) unique to the client computer has been described, but the present invention is not limited to this. For example, instead of the source IP address, a MAC address unique to the source (request source) client computer, that is, the source MAC address may be used. If necessary, change the “source IP address” in the flowchart of FIG.
C address ".

The above-described method of determining the service providing server computer based on the source IP address or the source MAC address can be said to be a determination method based on the source (request source) client computer. Is also applicable.

For example, the communication addressed to the IPS is based on the source IP address.
It can be specified by the address and the source port number unique to the process of the application (application program) on the source client computer side which needs to provide the service from the destination IPS (the server computer indicated by the communication). Therefore, when the server computer receives the Ethernet trailer 20 addressed to the IPS, any of the server computers to which the IP address IPS is set provides a service to the client computer (communicates with the client computer). ) Can be determined based on the IP address (that is, the source IP address) unique to the source (request source) client computer and the source port number. In this case, the IP requested by the application of the same client computer
In the communication addressed to S, if the process is different, communication with a different server computer is performed, and the load can be distributed. It is also possible to determine based on only the source port number.

In order to easily determine the server computer that provides the service based on the source IP address and the source port number, the server computer in which the IPS is set must be configured by the server computer 60A as in the above embodiment. And 60B, it is only necessary to determine whether the added value of the source IP address and the source port number is an odd number or an even number. That is, in the above embodiment, the transmission source I
Instead of determining the odd / even P address, the source I
The odd / even number of the sum of the P address and the source port number may be determined.

By the way, the load state of a plurality of server computers to which the IPS is set fluctuates. Therefore, the Ethernet trailer 2 addressed to the IPS from the client computer
If the server computer communicates with the plurality of server computers when it receives 0, and the server computer that communicates with the client computer is determined, the server computer with a small load at that time should provide the service. Becomes possible. This will be described using the system of FIG. 6 as an example.

In the system shown in FIG. 6, the server computer 6
0A and 60B are IPs from the client computer 60C.
It is assumed that the Ethernet trailer 20 addressed to S has been received. In this case, each server computer 60 started by the filter driver 600 (at step S26 in FIG. 7)
The communication 90 is performed between the determination devices 601 of A and 60B via the network 11 as shown in FIG. 9 to determine which one processes the Ethernet trailer 20 (the IP trailer 23 therein), that is, of the server computers 60A and 60B. It is determined which provides the service to the transmission source client computer 60C.

The server computer determining device 601 that has decided to provide the service returns “on” to the filter driver 600, and the server computer determining device 601 that has decided not to provide the service sends the filter driver 60.
Returns "off" for 0. This state may be maintained for a certain period of time by, for example, timer management.

In this way, the server computer providing the service can be dynamically determined for each communication.

[0088]

As described above in detail, according to the present invention, by installing a filter driver in the former stage of the network layer, it is not necessary to remodel a client application and further to set a name service server, without having to set a name service server. According to the present invention, a takeover can be realized, and according to the present invention, a filter driver is mounted in a stage preceding the network layer, so that a dedicated application or a dedicated hardware mechanism is not used and a layer 4 switch is used. Load distribution can be realized

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a cluster system according to a first embodiment of the present invention.

FIG. 2 is a schematic format of an Ethernet trailer.

FIG. 3 is a flowchart for explaining the operation in the embodiment.

FIG. 4 is a block diagram showing a configuration of a cluster system according to a second embodiment of the present invention.

FIG. 5 is a flowchart for explaining the operation in the embodiment.

FIG. 6 is a block diagram showing a configuration of a cluster system according to a third embodiment of the present invention.

FIG. 7 is a flowchart for explaining the operation in the embodiment.

FIG. 8 is a flowchart for explaining the operation in the embodiment.

FIG. 9 is a diagram illustrating a determination device 601 of the server computers 60A and 60B.
FIG. 4 is a diagram for explaining a method of determining a computer that provides a service by communication between the computers.

[Explanation of symbols]

10A, 10B, 40A, 40B, 60A, 60B ... server computers 10C, 40C, 60C ... client computers 11 ... network 100, 400, 600 ... filter drivers 100a, 400a, 400b ... flags 101 ... interface layer 102 ... network layer 105, 605: communication driver 106: flag operation mechanism 107, 407: flag operation command 108: network interface 601: judgment device

Claims (10)

[Claims] 1. A cluster system in which a service is taken over between server computers by communication using communication data including a network trailer in which a specific network address to be taken over is set as a destination network address, wherein each of the server computers A flag information holding means for holding flag information which can be set to be arbitrarily switched to one of a first state and a second state; and Does not perform filtering of the network trailer in the communication data, and in the case of the second state, performs filtering of the network trailer based on whether a destination network address in the network trailer is the specific network address. Perform the specific net A cluster system comprising: a filter driver for discarding the network trailer only when the address is a work address. 2. A cluster system in which a service is taken over between server computers by communication using communication data including a network trailer in which one of a plurality of specific network addresses to be taken over is set as a destination network address, Flag information, wherein each of the server computers is provided in correspondence with each of the plurality of specific network addresses, and holds flag information which can be arbitrarily and independently switched and set in any one of a first state and a second state. Holding means, when receiving communication data, referring to each of the flag information; if all are in the first state, filtering of a network trailer in the communication data is not performed; The destination network address in the trailer is in the second state And a filter driver that performs filtering for discarding the network trailer when the address matches one of the specific network addresses corresponding to the flag information. 3. Receiving communication data from a client computer including a network trailer in which a specific network address designating a server computer that provides a service is set as a destination network address, among the plurality of server computers, the specific network address. Is a cluster system that communicates with the client computer, wherein each of the server computers is activated when receiving communication data having the specific network address as a destination network address, and A determination unit that determines whether the own computer should provide a service based on the information about the source computer in the communication source, and sets corresponding flag information. Regardless of the destination physical address of the The network trailer in the communication data is taken out, the destination network address is checked, and the flag information indicating that the destination network address matches the specific network address and that the own computer should not provide the service is determined by the determination means. A cluster system comprising: a filter driver that discards the network trailer only when set, and otherwise passes the network trailer to a network layer. 4. The method according to claim 1, wherein the determining unit determines whether or not a predetermined part of a source network address, a source physical address, or a source port number in the communication data matches a predetermined value. The class system according to claim 3, wherein a state of the information is determined. 5. The method according to claim 1, wherein the determining unit determines that a predetermined portion of information obtained by combining at least two of the source network address, the source physical address, and the source port number in the communication data matches a predetermined value. The class system according to claim 3, wherein a state of the flag information is determined based on whether or not to perform the operation. 6. Upon receiving communication data from a client computer including a network trailer in which a specific network address designating a server computer that provides a service is set as a destination network address, said specific network address among a plurality of server computers. Is a cluster system that communicates with the client computer, wherein each of the server computers is activated when receiving communication data having the specific network address as the destination network address, and Means for determining whether a service should be provided and setting corresponding flag information; and, upon receiving the communication data, a network trailer in the communication data regardless of a destination physical address in the communication data. Take out and address The network trailer is checked only when the destination network address matches the specific network address and flag information indicating that the computer should not provide a service is set by the determination means. And a filter driver for passing the network trailer to the network layer in other cases, wherein each of the determination means communicates with each other to communicate with the only server computer which provides the service for each communication. A cluster system characterized in that: 7. A server computer applied to a cluster system in which a service is taken over between server computers by communication using communication data including a network trailer in which a specific network address to be taken over is set as a destination network address. A flag information holding unit that holds flag information that can be set to be arbitrarily switched to one of the first state and the second state; and refers to the flag information at the time of receiving communication data. In the case, the filtering of the network trailer in the communication data is not performed, and in the case of the second state, the filtering of the network trailer is performed based on whether a destination network address of the network trailer is the specific network address. The specific network Only if a work address, server computer, characterized by comprising discarding filter driver the network trailer. 8. Upon receiving communication data from a client computer including a network trailer in which a specific network address designating a server computer that provides a service is set as a destination network address, the specific network address among a plurality of server computers is specified. Is a server computer applied to a cluster system that communicates with the client computer, the server computer being activated when receiving communication data having the specific network address as a destination network address, A determination unit that determines whether the own computer should provide a service based on the information about the source computer in the communication source, and sets corresponding flag information. Regardless of the destination physical address of the The network trailer in the communication data is taken out, the destination network address is checked, and the flag information indicating that the destination network address matches the specific network address and that the own computer should not provide the service is determined by the determination means. A server driver that discards the network trailer only when set, and otherwise passes the network trailer to a network layer. 9. A network address takeover method in a cluster system in which a service is taken over between server computers by communication using communication data including a network trailer in which a specific network address to be taken over is set as a destination network address. In each of the server computers, flag information that can be arbitrarily set in one of the first and second states is held, and is disposed between the interface layer and the network layer when communication data is received. The filter driver refers to the flag information, does not perform filtering of the network trailer in the communication data in the first state, and does not perform filtering of the network trailer in the second state in the second state. If the destination network address is Performs filtering of the network trailer by whether a network address, the only if a particular network address, takeover method of network addresses, characterized in that so as to discard the network trailer. 10. Upon receiving communication data from a client computer including a network trailer in which a specific network address designating a server computer providing a service is set as a destination network address, the specific network address of a plurality of server computers Is a load balancing method applied to a cluster system in which one of the server computers configured to communicate with the client computer comprises: receiving communication data having the specific network address as a destination network address; On the basis of the information on the source computer of the above, determines whether or not the own computer should provide the service, and sets the flag information of the value corresponding to the determination result. With the filter driver placed between The network trailer in the communication data is taken out irrespective of the destination physical address in the communication data, and the destination network address is checked. This destination network address matches the specific network address. A load distribution method, wherein the network trailer is discarded only when it is indicated that the service should not be provided, and otherwise, the network trailer is passed to a network layer.