Redis03 - network configuration and heartbeat mechanism of redis

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The article brief introduction ： Introduce Redis Network configuration and heartbeat mechanism

Redis Network configuration and heartbeat mechanism

Redis Under the installation root directory of redis.conf The configuration file ,Redis This configuration file will be loaded at startup , Work according to the configuration at run time . Sometimes we take out this document , Store in a separate location , When starting, you must specify which configuration file to use , This document will take effect .Redis The network related configuration of is as follows .

bind： binding IP Address , Other machines can use this IP visit Redis, The default binding 127.0.0.1, That is, any host ip Address , In order to facilitate safety control , We generally recommend changing it to fixed IP Address .
port： To configure Redis Ports occupied , The default is 6379.
tcp-keepalive：TCP Connect the survival strategy , Can pass tcp-keepalive Configuration item to set , The unit is in seconds , If set to 60 second , be server End meeting every 60 Second to connect idle clients once ACK request , To check if the client has hung up , For unresponsive clients, the connection is closed . If set to 0, No life preservation test will be carried out .

Demo Next , Execute the following command , Modify the bound ip Address .

/opt/redis-5.0.2$ sudo vim redis.conf

start-up redis The server .

redis-server redis.conf &

At this time, if there is no ip Executing client startup cannot start

redis-cli

An error is as follows .

Could not connect to Redis at 127.0.0.1:6379: Connection refused
not connected> 

here ctrl Add C Back to the command line interface , Appoint ip And port startup .

[email protected]:/opt/redis-5.0.2$ redis-cli -h 192.168.199.213 -p 6379
192.168.199.213:6379> 

If you need to close redis The server also needs to specify ip And port number , Because the closing operation is essentially a request sent by the client to the server .

 redis-cli -h 192.168.199.213 -p 6379 shutdown

If you execute the above command, the following error message appears .

This is because of your redis-server Is it through root User initiated , and shutdown The operation needs to save the data , You need write permission to the file ( Local users may not ). At this point, we first shut down the server brutally redis-server

$ ps -ef|grep redis
wangzhou    7155    6648  0 16:39 pts/0    00:00:04 redis-server 192.168.199.213:6379
wangzhou    7877    6648  0 17:15 pts/0    00:00:00 grep --color=auto redis

$ kill -9 7155

Bring it with you when you restart the service sudo

sudo redis-server redis.conf &

Connect the client later , You can use the client to shut down the server normally .

TIPS：
Using the server is recommended in root Start or use under the user sudo Command

Now please think about a question , The number of clients that the server can keep connected is limited , If the client does not actively disconnect after connecting , Is the connection always maintained ？ Won't this waste our resources ？ therefore ,redis The developers of provide a mechanism to deal with this situation . The server will send requests to the client regularly , If the client is still actually using the server , It will return " Activate " The state of . Parameters in the above configuration tcp-keepalive It is used to set the time interval for the server to send requests .

In development , We generally recommend setting this time to 60s, Specifically, adjust according to the performance of the server .