Docker client
Docker The client is very simple , We can enter it directly Docker Command to view all command options of Docker client.
xxx@xxx:~# docker
You can use the command docker command --help Learn more about the use of the specified Docker command.
For example, we want to view docker stats Specific use of instructions:
xxx@xxx:~# docker stats --help
Container use
Get image
If we do not have a ubuntu image locally, we can use the docker pull command to load the ubuntu image:
$ docker pull ubuntu
Start container
The following command uses ubuntu image to start a container. The parameter is to enter the container in command line mode:
$ docker run -it ubuntu /bin/bash
Parameter Description:
- -i: Interactive operation.
- -t: Terminal.
- ubuntu: ubuntu image.
- /bin/bash: after the image name is the command. Here we want an interactive Shell, so we use / bin/bash.
To exit the terminal, enter exit:
root@ed09e4490c57:/# exit
Start a container that has stopped running
View all container commands as follows:
$ docker ps -a
Click the picture to view the larger picture:
Start a stopped container using docker start:
$ docker start b750bbbcfd88
Background operation
In most scenarios, we want the docker service to run in the background. We can - d Specifies the operating mode of the container.
$ docker run -itd --name ubuntu-test ubuntu /bin/bash
Note: added - d The parameter will not enter the container by default. If you want to enter the container, you need to use the instruction docker exec (described below).
Stop a container
The command to stop the container is as follows:
$ docker stop <container ID>
Stopped containers can be restarted through docker restart:
$ docker restart <container ID>
Enter container
in use - d Parameter, the container will enter the background after starting. If you want to enter the container at this time, you can enter it through the following instructions:
-
docker attach
-
Docker exec: it is recommended that you use the docker exec command, because exiting the container terminal will not cause the container to stop.
attach command
The following demonstrates using the docker attach command.
$ docker attach 1e560fca3906
be careful: Exiting from this container will cause the container to stop.
exec command
The following demonstrates using the docker exec command.
docker exec -it 243c32535da7 /bin/bash
be careful: If you exit from this container, the container will not stop, which is why it is recommended docker exec The reason for this.
For more parameter descriptions, please use docker exec --help Command view.
Export and import containers
Export container
If you want to export a local container, you can use docker export Command.
$ docker export 1e560fca3906 > ubuntu.tar
Export the container 1e560fca3906 snapshot to the local file ubuntu.tar.
This exports the container snapshot to a local file.
Import container snapshot
You can use docker import to import from the container snapshot file as an image. The following example imports the snapshot file ubuntu.tar into the image test/ubuntu:v1:
$ cat docker/ubuntu.tar | docker import - test/ubuntu:v1
In addition, you can also import by specifying a URL or a directory, for example:
$ docker import http://example.com/exampleimage.tgz example/imagerepo
Delete container
Delete container usage docker rm Command:
$ docker rm -f 1e560fca3906
The following command can clean up all containers in the terminated state.
$ docker container prune
Run a web application
The container we ran earlier is of no particular use.
Next, let's try to build a web application using docker.
We will run a Python Flask application in the docker container to run a web application.
xxx@xxx:~# docker pull training/webapp # Load image xxx@xxx:~# docker run -d -P training/webapp python app.py
Parameter Description:
-
-d: Let the container run in the background.
-
-P: Randomly map the network ports used inside the container to the hosts we use.
View WEB application container
use docker ps To view the containers we are running:
xxx@xxx:~# docker ps CONTAINER ID IMAGE COMMAND ... PORTS d3d5e39ed9d3 training/webapp "python app.py" ... 0.0.0.0:32769->5000/tcp
There is more port information here.
PORTS0.0.0.0:32769->5000/tcp
Docker opens 5000 ports (the default Python Flask port) to map to host port 32769.
At this time, we can access the WEB application through the browser
We can also pass - p Parameter to set different ports:
xxx@xxx:~$ docker run -d -p 5000:5000 training/webapp python app.py
docker ps view running containers
xxx@xxx:~# docker ps CONTAINER ID IMAGE PORTS NAMES bf08b7f2cd89 training/webapp ... 0.0.0.0:5000->5000/tcp wizardly_chandrasekhar d3d5e39ed9d3 training/webapp ... 0.0.0.0:32769->5000/tcp xenodochial_hoov
The 5000 port inside the container is mapped to the 5000 port of our local host.
Shortcuts to network ports
adopt docker ps Command to view the port mapping to the container, docker Another shortcut is also provided Docker port, using docker port You can view the port number of the host mapped to a certain port of the specified (ID or name) container.
The web application container ID we created above is bf08b7f2cd89 Name is wizardly_chandrasekhar.
I can use docker port bf08b7f2cd89 or docker port wizardly_chandrasekhar To view the mapping of container ports.
xxx@xxx:~$ docker port bf08b7f2cd895000/tcp -> 0.0.0.0:5000 xxx@xxx:~$ docker port wizardly_chandrasekhar5000/tcp -> 0.0.0.0:5000
View WEB application log
docker logs [ID or name] can view the standard output inside the container.
xxx@xxx:~$ docker logs -f bf08b7f2cd89 * Running on (Press CTRL+C to quit)192.168.239.1 - - [09/May/2016 16:30:37] "GET / HTTP/1.1" 200 -192.168.239.1 - - [09/May/2016 16:30:37] "GET /favicon.ico HTTP/1.1" 404 -
-f: Give Way docker logs Like use tail -f Output the standard output inside the container.
From the above, we can see that the application uses port 5000 and can view the access log of the application.
View the process of WEB application container
We can also use docker top To view the processes running inside the container
xxx@xxx:~$ docker top wizardly_chandrasekhar UID PID PPID ... TIME CMD root 23245 23228 ... 00:00:00 python app.py
Check WEB application
use docker inspect To view the underlying information of Docker. It will return a JSON file that records the configuration and status information of the Docker container.
xxx@xxx:~$ docker inspect wizardly_chandrasekhar[
{
"Id": "bf08b7f2cd897b5964943134aa6d373e355c286db9b9885b1f60b6e8f82b2b85",
"Created": "2018-09-17T01:41:26.174228707Z",
"Path": "python",
"Args": [
"app.py"
],
"State": {
"Status": "running",
"Running": true,
"Paused": false,
"Restarting": false,
"OOMKilled": false,
"Dead": false,
"Pid": 23245,
"ExitCode": 0,
"Error": "",
"StartedAt": "2018-09-17T01:41:26.494185806Z",
"FinishedAt": "0001-01-01T00:00:00Z"
},......
stop it WEB Application container
xxx@xxx:~$ docker stop wizardly_chandrasekhar
wizardly_chandrasekhar
restart WEB Application container
For containers that have been stopped, we can use the command docker start To start.
xxx@xxx:~$ docker start wizardly_chandrasekhar
wizardly_chandrasekhardocker ps -l Query last created container:
# docker ps -l CONTAINER ID IMAGE PORTS NAMES bf08b7f2cd89 training/webapp ... 0.0.0.0:5000->5000/tcp wizardly_chandrasekhar
Running container, we can use docker restart Command to restart.
Remove WEB application container
We can use docker rm Command to delete unnecessary containers
xxx@xxx:~$ docker rm wizardly_chandrasekhar wizardly_chandrasekhar
When deleting a container, the container must be stopped, otherwise the following error will be reported
xxx@xxx:~$ docker rm wizardly_chandrasekharError response from daemon: You cannot remove a running container bf08b7f2cd897b5964943134aa6d373e355c286db9b9885b1f60b6e8f82b2b85. Stop the container before attempting removal or force remove