Load Balancing Method, Apparatus, and System

A load balancing method, applied to a load balancing system comprising a load balancer and at least one service node, wherein a virtual switch and at least one backend server are configured to run on the at least one service node, wherein an Internet Protocol (IP) address of a logical interface of the at least one backend server comprises an IP address of the load balancer, and wherein the method comprises:

• receiving, by the load balancer, an access request from a client;
• selecting, by the load balancer, a destination backend server for the client;
• changing, by the load balancer, a destination address of the access request to an IP address of a virtual network interface card of the destination backend server;
• sending, by the load balancer, the access request to a destination service node on which the destination backend server is located;
• receiving, by a virtual switch on the destination service node, the access request;
• changing, by the virtual switch on the destination service node, the destination address of the access request to the IP address of the load balancer;
• sending, by the virtual switch on the destination service node, the access request to the destination backend server;
• receiving and processing, by the destination backend server, the access request;
• and
• returning, by the destination backend server, an access response to the client, wherein a source address of the access response comprises the IP address of the load balancer.

A service node, comprising:

• at least one backend server;
• and
• a virtual switch coupled to the at least one backend server and configured to:
• receive an access request of a client from a load balancer, wherein the at least one backend server is allocated by the load balancer to the client to provide a service, wherein an Internet Protocol (IP) address of a logical interface of the at least one backend server comprises an IP address of the load balancer, and wherein a destination address of the access request comprises an IP address of a virtual network interface card of the at least one backend server;
• change the destination address of the access request to the IP address of the load balancer;
• and
• send the access request to the at least one backend server, and
• wherein the at least one backend server is configured to:
• receive and process the access request;
• and
• return an access response to the client, wherein a source address of the access response comprises the IP address of the load balancer.

A load balancing method, wherein the method is executed on a service node, wherein a virtual switch and at least one backend server are configured to run on the service node, wherein the at least one backend server is allocated by a load balancer to a client to provide a service, wherein an Internet Protocol (IP) address of a logical interface of the at least one backend server comprises an IP address of the load balancer, and wherein the method comprises:

• receiving, by the virtual switch, an access request of the client from the load balancer, wherein a destination address of the access request comprises an IP address of a virtual network interface card of the at least one backend server;
• changing, by the virtual switch, the destination address of the access request to the IP address of the load balancer;
• sending, by the virtual switch, the access request to the at least one backend server;
• receiving and processing, by the at least one backend server, the access request;
• and
• returning, by the at least one backend server, an access response to the client, wherein a source address of the access response comprises the IP address of the load balancer.

A load balancing system in a virtualization environment, comprising:

• a load balancer;
• and
• at least one service node coupled to the load balancer,
• wherein a virtual switch, a virtual router, and at least one backend server are configured to run on the at least one service node,
• wherein the load balancer and the at least one backend server are located on a same tenant network,
• wherein an Internet Protocol (IP) address of a logical interface of the at least one backend server comprises a virtual IP address of the load balancer,
• wherein the load balancer is configured to:
• receive an access request from a client;
• select a destination backend server for the client;
• change a destination address of the access request to a local area network IP address of the destination backend server;
• and
• send the access request to a destination service node on which the destination backend server is located,
• wherein a virtual router on the destination service node is configured to:
• receive the access request;
• change the destination address of the access request from the local area network IP address of the destination backend server to an IP address of a virtual network interface card of the destination backend server according to a first flow table;
• and
• send the access request to a virtual switch on the destination service node, wherein the virtual switch on the destination service node is configured to:
• change the destination address of the access request to an IP address of a logical interface of the destination backend server according to a second flow table;
• and
• send the access request to the destination backend server,
• wherein the destination backend server is configured to:
• receive and process the access request;
• and
• return an access response, wherein a source address of the access response is changed to the virtual IP address of the load balancer, and
• wherein the virtual router on the destination service node is further configured to change the source address of the access response to a public IP address of the load balancer according to a third flow table.