Shulou(Shulou.com)06/03 Report--

The following brings you a detailed introduction of the meaning, classification and working mode of LVS load balancing cluster, hoping to bring some help to you in practical application. Load balancing involves more things, there are not many theories, and there are many books on the Internet. Today, we will use the accumulated experience in the industry to do an answer.

Enterprise Cluster Application Overview the meaning of cluster Cluster, cluster, cluster consists of multiple hosts, but only as a whole in Internet applications, as the site has higher and higher requirements for hardware performance, response speed, service stability, data reliability and so on. According to the target difference of the cluster, it can be divided into three types: load balancing cluster, high availability cluster, high performance computing cluster, load balancing cluster (Load Balance Cluster), to improve the impact of the application system, to handle as many access requests as possible, and to reduce latency. Achieving high concurrency and high load (LB) overall performance LB load distribution depends on the shunting algorithm of the master node High availability Cluster (High Availability Cluster) aims to improve the reliability of the application system, minimize downtime and ensure service continuity To achieve high availability (HA) fault tolerance, the working mode of HA includes duplex mode and master-slave mode High performance Computing Cluster (High Performance Computer Cluster) aims to improve the CPU computing speed of application systems, expand hardware resources and analytical capabilities, and obtain high performance computing (HPC) capabilities equivalent to large and supercomputers. The high performance of high performance computing clusters depends on "distributed computing" and "parallel computing". The CPU, memory and other resources of multiple servers are integrated through dedicated hardware and software to realize the computing power load balancing cluster work mode that only large and supercomputers have; load balancing cluster is the most widely used cluster scheduling technology in enterprises at present. There are three working modes, address translation, IP tunnel, direct routing, NAT mode, address translation (Network Address Translation), or NAT mode. Similar to the private network structure of the firewall, the load scheduler acts as the gateway of all server nodes, that is, as the access entrance of the client and the access exit of each node responding to the client. The server node uses a private IP address, which is located in the same physical network as the load scheduler. The security is better than the other two modes: TUN mode, IP tunnel (IP Tunnel) referred to as TUN mode, using an open network structure. The load scheduler only acts as the access entrance for the client, and each node responds directly to the client through its own Internet connection, instead of going through the load scheduler server nodes scattered in different locations in the Internet, and has independent public network IP addresses. It communicates with the load scheduler through a private IP tunnel, DR mode direct routing (Direct Routing) is referred to as DR mode, and adopts a semi-open network structure, which is similar to the structure of TUN mode. However, each node is not scattered everywhere, but is located in the same physical network load scheduler and connects with each node server through the local network. There is no need to establish a dedicated IP tunnel load balancing cluster architecture, layer 1, load scheduler (Load Balancer or Director) layer 2, server pool (Server Pool) layer 3, shared storage (Share Storage).

On the load balancing solution of LVS Virtual Server Linux Virtual Server for Linux Kernel May 1998 [root@localhost] # modprobe ip_vs / / confirm kernel support for LVS created by Dr. Zhang Wensong of our country [root@localhost ~] # cat / proc/net/ip_vsIP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Scheduler Flags- > RemoteAddress:Port Forward Weight ActiveConn InActConnLVS load scheduling algorithm polling (Round Robin) distributes the received access requests to each node in the cluster (real server) in turn. ) treat each server equally Regardless of the actual number of connections of the server and the system load weighted polling (Weighted Round Robin), the scheduler can automatically query the load of each node according to the processing capacity of the real server, and dynamically adjust its weight to ensure that the server with strong processing capacity undertakes more access traffic and minimum connections (Least Connections) according to the number of connections established by the real server. Priority is given to the node with the least number of connections to receive access requests.

Weighted least connection (Weighted L east Connections)

In the case of large differences in the performance of server nodes, you can automatically adjust the weights for real servers. Nodes with higher weights will bear a larger proportion of active connection loads. Use ipvsadm tools LVS cluster creation and management to create virtual servers to add, delete server nodes to view clusters and save load distribution policies.

After reading the above detailed introduction of the meaning, classification and working mode of LVS load balancing cluster, if there is anything else you need to know, you can find what you are interested in in the industry information or find our professional and technical engineer to answer, the technical engineer has more than ten years of experience in the industry.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.