Knowledge supplement: basic usage of redis based on docker

Redis brief introduction

Redis（Remote Dictionary Server） By Salvatore Sanfilippo Developed key-value（ Key value pair ） The storage system .

Compare traditional databases with NoSQL database

	Traditional database （ Relational database ）	NoSQL
representative	MySQL、Oracle、SQL Server	Redis、MongoDB
data structure	With “ surface ” In the form of （ The table structure has strict data schema constraints ）	Use a relatively simple data structure （ such as Redis Key value pairs are used ）
physical position	Stored on a hard disk （ Routine situation ）	Stored in memory （ Supports persistence to disk ）
Applicable scenario	Store large-scale data	Small amount of data but certain performance requirements

According to the project practice experience in the industry ,Redis The main advantages are as follows ：

1. Because the data is stored in memory , Therefore, the speed of searching data is faster .
2. More data types are supported , For example, support string 、 Lists and hash tables .
3. Can support transactions , At the same time, it supports data persistence , That is, the data in the memory can be stored in the hard disk .

however ,Redis There are also some disadvantages ：

1. Redis It is difficult to support online capacity expansion , Especially in the cluster scenario , When the storage capacity reaches the upper limit , Online capacity expansion will be very difficult .
2. Redis It's memory based , If a large amount of data is stored in a short time , May cause memory problems , For example, there will be OOM（ out of memory ） abnormal .
3. Redis The working time is based on single thread , So we can't make full use of the CPU.

In the project , be based on Redis Advantages and disadvantages , It is usually used for caching 、 seckill 、 Counters, leaderboards and other scenarios closely related to performance （ And it is more suitable to provide services in the form of distributed clusters ）.

Docker brief introduction

Docker Three concepts of ： Warehouse 、 Mirror image 、 Containers

• Warehouse ： Code Center , Can be locally , It can also be remotely , The ability to store images .
• Mirror image ： Static .
• Containers ： Mirror runtime entities （ Objects instantiated by classes ）.

In the sense of development Docker contain Docker Software and Docker command .

Docker Official website ：https://www.docker.com/

Check the installed version （ Command line ）：docker version

View local image ：docker images

Download mirroring ：docker pull Mirror name : label （ If you don't specify a label , The default is latest, The latest version ）

delete mirror ：docker rmi Mirror name : label   or   docker rmi  Mirror image ID

Running the mirror ：docker run -it  Mirror name : label /bin/bash

（-it Means interactive operation at the terminal ,/bin/bash Indicates the command to be executed after the container is started , Here is the start shell）

View all current containers ：docker ps -a（ By default, only those in Up The container of state , With parameters -a To display all ）

Delete container ：docker rm  Containers ID

function Redis Mirror image ：docker run -itd --name myFirstRedis -p 6379:6379 redis:lastest

-it Interactive operation at the terminal

d Means running in the background

--name Specify the name of the container

-p Of the specified container 6379 Port mapping to host （ function Docker Machine ） Of 6379 port （ This allows you to host outside the container ip:6379 The way to access Redis service ）

（ be known as myFirstRedis The container of is in Up state , And through 6379 The port provides external services ）

see Redis Activation effect ：docker logs myFirstRedis

adopt docker exec Get into Redis Containers ：docker exec -it myFirstRedis /bin/bash

（docker exec Indicates that the command is executed in the run container ,/bin/bash Indicates the specific command to be executed , Here is the opening shell）

 （ Enter the file named myFirstRedis The container of , The container is based on Linux operating system . Re pass redis-cli Command to create a client —— Connected to the container Redis The server , Subsequently passed set The command creates a value of Hugo Of name Variable , Re pass get Command to get name The value of the variable ）

 （ Pass twice exit go back to Windows Command line . The first time you quit is with redis-cli Entering Redis Run window , The second time you quit is with docker exec Order to enter Linux Containers ）

Stop container ：docker stop myFirstRedis（ Be careful ： What stops is the container , instead of Redis service ）

Restart container ：docker start myFirstRedis or  docker restart myFirstRedis

（ difference ： direct docker restart The file system associated with the container will not be mounted , In other words, the changed configuration item parameters may not be loaded . So it is suggested to docker stop, Again docker start）

see Redis Version of

Open the container , Into the container shell

see Redis Server version ：redis-server --version

see Redis Client version ：redis-cli --version

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The whole process is sorted out ：

1. install Docker Software
2. Enter... On the command line docker pull redis Download the latest Redis Mirror image
3. Input docker images To confirm the image
4. Input docker run -itd --name myFirstRedis -p 6379:6379 redis:latest, Create and run a container based on the image
5. Input docker ps -a Check the corresponding created container
6. Input docker stop myFirstRedis Let the container enter Exited state
7. Input docker rm myFtrstRedis Delete container （ Before deleting, you must ensure Exited state ）
8. Input docker start myFirstRedis Start in Exited The container of state
9. After the container is created and started , Can pass docker logs myFirstRedis Check the container Redis Start up of the server
10. It can also be done through docker exec -it myFirstRedis /bin/bash Enter the container and start shell
11. start-up shell And then you can go through redis-cli Create a connection to Redis The client side of the server （ Then, various Redis command , such as exit Exit command ）
12. If you need to restart the container , First of all docker stop myFirstRedis, Again docker start myFirstRedis To achieve
13. Need to stop Redis Server , Through the first redis-cli Command to connect to the server , Input again shutdown To achieve

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Inductive graph

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