Shulou(Shulou.com)05/31 Report--

Today, I will talk to you about what the server status monitoring keepalived is like. Many people may not know much about it. In order to make you understand better, the editor has summarized the following contents for you. I hope you can get something according to this article.

Introduction to keepalived:

Keepalived is a software similar to layer3, 4-5 switching mechanism, which is what we usually call layer 3, layer 4 and layer 5 switching. The role of Keepalived is to detect the status of the web server. If a web server crashes or fails, Keepalived will detect and remove the malfunctioning web server from the system. When the web server works normally, Keepalived automatically adds the web server to the server farm. All these tasks are completed automatically, without human intervention, and all you need to do is to repair the faulty web server.

How keepalived theory works:

Layer3,4&5 works in the IP layer, TCP layer, and application layer of the IP/TCP protocol stack. The principles are as follows:

When Layer3:Keepalived works in the Layer3 way, Keepalived periodically reports to the servers in the server farm

Send an ICMP packet (that is, the Ping program we usually use). If the IP address of a service is not activated, Keepalived reports that the server is invalid and removes it from the server farm. A typical example of this situation is that a server has been illegally shut down. The way of Layer3 is to take the validity of the IP address of the server as the standard of whether the server is working properly or not. This approach will be used in this article.

Layer4: if you understand the way Layer3 works, Layer4 is easy. Layer4 mainly determines whether the server is working properly or not based on the status of the TCP port. For example, the service port of web server is generally 80. If Keepalived detects that port 80 is not started, Keepalived will remove the server from the server farm.

Layer5:Layer5 works in a specific application layer, which is a little more complex than Layer3,Layer4 and takes up more bandwidth on the network. Keepalived will check whether the server program is running properly according to the user's settings, and if it does not match the user's settings, Keepalived will remove the server from the server farm.

Keepalived function:

With the growth of your website business, the server of your website is under more and more pressure? Need a load balancing solution! Commercial hardware such as F5 is too expensive, and you are entrepreneurial interconnected companies. How can you effectively save costs and unnecessary waste? At the same time to achieve the same high-performance and high-availability functions as commercial hardware? Is there a good extensible solution for load balancing?

After reading the above, do you have any further understanding of the server health monitoring keepalived? If you want to know more knowledge or related content, please follow the industry information channel, thank you for your support.

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.