docker basic commands

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1. Check docker version

docker version

2. View docker details

docker info

3. View the docker help command

docker help

If you forget how to use the specific parameters of a command, follow it with – help

• give an example

How to use the parameters of query ps

docker ps --help

4. Start docker

systemctl start docker 

5. Close docker

systemctl stop docker

6. Restart docker

systemctl restart docker

7. Self starting docker

systemctl enable docker

8. Check docker running status

Green indicates that it is currently running

systemctl status docker

docker image command

1. View the current image

docker images

2. Search image

Parameter Description:

Filter query results according to the provided parameters
-f , --filter filter Filter output based on conditions provided

# Search command
docker search Image name
# For example, search jenkins
docker search jenkins 
# For example, search jenkins to download more than 5000 image files
docker search -f

• Search jenkins image file
  
• Search jenkins image files with start more than 5000
  

3. Pull the image file

Without tag (version number), the latest version of the image in the docker warehouse is pulled. Latest plus: tag is the specified version

docker pull Image name
# Pull MySQL
docker pull mysql

• When pulling mysql, it should be noted that if the mirrored version information is not added, the latest version is pulled by default
  
• View the new mysql image file
  

Let's try to pull an image file with version information

docker official image search

Official website

Version information

• Pull the mysql image and the version is 5.7.37

docker pull mysql:5.7.37

4. Run the image file

# Pull tomcat image
docker pull tomcat
# Start tomcat directly without any operation
docker run tomcat

After starting the tomcat image, you will find that the cursor disappears and nothing can be done. You can use ctrl+c to jump out (Note: Although this method can exit the container, this command is wrong. See the container command below for details)

5. Delete the image file

The precondition is that the current image file is not used by any container, just like someone in the house. You can't directly open the excavator for demolition

#Delete a single mirror file
docker rmi -f Image name/image id
# Delete the latest mysql image file
docker rmi -f 5b4c624c7fe1
# You can try the following by yourself
#Delete multiple image ID s or separate images with spaces 
docker rmi -f Image name/image ID Image name/image ID Image name/image ID
#Delete all images - a means to display all and - q means to display only ID s
docker rmi -f $(docker images -aq)

• Force deletion of mirrored files

docker images rm  Image name/image ID

That's all for the basic command of the image. A more complex docker run command will be used below to start the container according to the image

6. Save the image file

Save our image as a tar compressed file to facilitate image transfer and saving, and then load the image on any server with docker installed

Syntax:

docker save Image name/image ID -o Where and by what name is the image saved
# Back up our jenkins image
docker save 55860ee0cd73 -o /tmp/jenkinsbeifen.tar

• Backup jenkins
  
• View backup files

7. Load the image file tar

Load image files migrated from other places

grammar

docker load -i Image save file location

# Load jenkins container
docker load -i /tmp/jenkinsbeifen.tar

• Load container
  

docker container command

1. View the list of currently running containers

docker ps

2. View all containers - including running and stopped containers

docker ps -a

3. Run a container

grammar

# -it means interactive startup with the container, - d means that the container can be run in the background (daemon)  
# --Name name of the container to run / bin/bash interaction path
docker run -it -d --name Alias image name to be taken:Tag /bin/bash 

Let's take redis as an example to pull and run the redis container

• Create and run containers

#1. Pull the redis image
docker pull redis:5.0.5
#2. Command start
docker run -it -d --name redis001 redis:5.0.5 /bin/bash

• View container
  

This time we see
redis uses port 6379. Can we access it when we turn off the firewall or turn on the security group?

# netstat is a console command. It is a very useful tool for monitoring TCP/IP network. It can display routing table, actual network connection and status information of each network interface device
netstat -untlp

• Check the port and no 6379 is found
  

Use the redis desktop manger connection to test

Why not? It has been confirmed that the redis container in docker is running and occupies port 6379?

Because: the occupied 6379 port is only the internal port in the container and has no connection with the 6379 port of the host. We can access this redis example through the host Ip:6379, which is naturally not found!

By default, we cannot directly access the container through the port of the host (the server where docker is installed), because the port opened by the docker container has no connection with the port of the host

If the external wants to access the container, the port in the container must be bound with the port of the host. This formal concept is called container port mapping

With port mapping, we can bind the host port to the container port. For example, we can bind the 6379 port of the host to the redis 6379 port of the container, and then access the host Ip:6379 to access the corresponding container!

4. Container port mapping

Next, we will demonstrate the container port mapping

Stop the container first

docke stop container id/Container name
# Stop redis
docker stop redis001

Then delete the container

# Delete container
docker rm -f fb4e089b9a67

Port mapping syntax

-p host port: container port

Still use the redis image in front to try to map port 6379 to 8888 of the server. If it is successful, we will access the container redis002 in our docker when we access port 8888 of the server

-p 8888:6379 parsing
Map port 6379 inside the container to port 8888 of docker host (the server where docker is installed is its array machine)
Then you can access port 6379 of docker container through external access to port 8888 of host computer

docker run -itd --name redis002 -p 8888:6379 redis:5.0.5 /bin/bash

Then we'll reconnect and find it successful

So are there any restrictions on container port mapping?

Yes, although the environment between each container is isolated, each port of the host machine is one. Port 8888 is bound by redis002 container, so all other containers can't use port 8888!!!

5. Enter the container

Mode 1:

# grammar
docker exec -it Container name/container ID /bin/bash

#Enter the redis001 container in front   
docker exec -it redis001 /bin/bash

• Enter container
  

Mode 2:

docker attach Container name/container ID
# Enter redis
docker attach redis001

• Enter container
  

6. Exit the container

#-----When you exit directly without adding - D (persistent running container), the container will be closed  
exit
# Elegant proposal - the container will not be closed whether the - d parameter is added or not
Ctrl + p + q

• immediate withdrawal
  
• Graceful exit
  

7. Stop the container

docker stop container ID/Container name
# Stop redis001
docker stop redis001

8. Restart the container

docker restart container ID/Container name
# Restart redis001
docker restart redis001

9.kill container

docker kill Container name/container id

# Kill redis002 container
docker kill redis002