Alibaba Cloud's load balancing supports TCP, UDP and HTTP, etc., because my website is the HTTP protocol.
"Alibaba Cloud provides load balancing services at four layers (TCP and UDP) and seven layers (HTTP and HTTPS). The network layer is the reference model for open system interconnection proposed by the International Organization for Standardization (ISO) in 1978, which is the famous OSI/RM model (Open System Interconnection/Reference Model). It divides the communication protocol of computer network architecture into seven layers, from bottom to top: Physics Layer, Data Link Layer, Network Layer, Transport Layer, Session Layer, Presentation Layer, and Application Layer）。 The fourth layer completes the data transmission service, and the upper three layers are user-oriented. ”
Configure health checks that always prompt for exceptions!!!
Let's take a look at how HTTP health checks work:
The health check in HTTP mode detects the head request, and the Tengine node server sends an HTTP header request and then compares the return code parameters to verify whether the backend service is abnormal.
In fact, it is to send an http request and check the status code of the return request header, at first, I thought it was a problem with my security group settings
Finally, one thing that comes to mind, I nginx filters requests without user-agent, is this the issue?
It is estimated that Alibaba Cloud monitoring checks that there is no user-agent in the http request, and my server directly returns the 403 status code, and the solution is as follows:
Check the http_4xx http_5xx in the normal status code to solve the problem!!
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Posted on 7/25/2017 10:16:50 PM
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