How to read nginx logs

There are two main types of nginx logs: access logs and error logs. The access log mainly records every request of the client to access nginx, and the format can be customized; the error log mainly records the log when the client accesses nginx and an error occurs, and the format does not support customization. Both logs can be optionally turned off.

Through the access log, you can get relevant information such as the user’s geographical origin, jump source, usage terminal, number of visits to a certain URL; through the error log, you can You can get the performance bottleneck of a certain service or server in the system. Therefore, by making good use of logs, you can get a lot of valuable information.

Access Log

[Access.log]

log_format main '$remote_addr $remote_user [$time_local] "$request" $http_host ' '$status $upstream_status $body_bytes_sent "$http_referer" ' '"$http_user_agent" $ssl_protocol $ssl_cipher $upstream_addr ' '$request_time $upstream_response_time';

Description:

##$time_local 18/Jul/ 2012:17:00:01 0800 ##$request and $http_host or domain name ) User Terminal Agent ##SSL TLSv1 ##$ssl_cipher $upstream_addr , that is, the address of the host that actually provides the service ##$request_time

#Variable name	Variable description	Example
$remote_addr	Client address	##113.140. 15.90
##$remote_user Client user name		-
Access time and time zone
Requested URI	HTTPProtocol "GET /pa/img/home/logo-alipay-t.png HTTP/1.1"
The request address is the address you enter in the browser ( IP	img.alipay.com	##10.253.70.103 ##$status
HTTPRequest Status	200	$upstream_status
##upstreamstatus	200
$body_bytes_sent	The size of the file content sent to the client	547
#$http_referer	Jump source	"https://cashier.alipay.com.../"
##$http_user_agent		"Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1 ; Trident/4.0; SV1; GTB7.0; .NET4.0C;
##$ssl_protocol	Protocol Version
Algorithm in exchange data	RC4-SHA
The address of the background upstream	10.228.35.247:80
The total time of the entire request	0.205	##$upstream_response_time
During the request ,upstreamResponse time	##0.002	Note:The value of $http_host is related to the value you enter in the browser. Error log ( When the user is connecting, if the backend When the user reads data after a successful connection, if the user encounters a backend ##"(111: Connection refused) while sending request to upstream " When Nginx and "(110: Connection timed out) while connecting to upstream" nginx timed out when connecting to the subsequent " (110: Connection timed out) while reading upstream" nginx timed out while reading the response from "(110: Connection timed out) while reading response header from upstream" nginx timed out while reading response headers from "(110: Connection timed out) while reading upstream" nginx timed out while reading the response from "(104: Connection reset by peer) while connecting to upstream" upstream sent "upstream sent invalid header while reading response header from upstream" The response header sent by upstream is invalid "upstream sent no valid HTTP/1.0 header while reading response header from upstream" The response header sent by upstream is invalid "client intended to send too large body" 1M, the ##"reopening logs" ##"could not add new SSL session to the session cache while SSL handshaking" ssl_session_cache large and small, etc. Cause creation "send() failed (111 : Connection refused)" ##Error message Error description "upstream prematurely (premature)closed connection" The exception that occurs when requesting uri is caused by the user disconnecting whenupstream has not returned a response to the user. It has no impact on the system and can be ignored ##"recv() failed (104: Connection reset by peer)" 1) The number of concurrent connections of the server exceeds its capacity, and the server will Down some of the connections;( 2) The client closed the browser, but the server is still sending data to the client; ( 3) The browser clicked Stop "(111: Connection refused) while connecting to upstream" upstream hangs or is blocked, the user will receive this error "(111: Connection refused) while reading response header from upstream" Upstream hangs up or is unavailable, you will receive this error upstream are successfully connected and sending data, if the backend upstream hangs or is unavailable, you will receive this Error upstream upstream upstream upstream RST to reset the connection is used to set the client requests that are allowed to be accepted. The maximum value of the content, the default value is body sent by the client exceeds the set value User sends kill -USR1 command "gracefully shutting down", USEkill -WINCH instruction "no servers are inside upstream" upstream Deploymentserver ##"no live upstreams while connecting to upstream" upstream下下server全都挂了 "SSL_do_handshake() failed" SSL handshake failed "SSL_write( ) failed (SSL:) while sending to client" ## "(13: Permission denied) while reading upstream" "(98: Address already in use) while connecting to upstream" "(99: Cannot assign requested address) while connecting to upstream" "ngx_slab_alloc() failed: no memory in SSL session shared cache" ssl_session_cache large and small, etc. cause creation ##

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