Docker operation in Centos7

1. Download Nginx

[[Email protected] my. shells]# Docker imagesrepository          TAG                 IMAGE ID            CREATED             sizedocker.io/redis     latest              1E70071F4AF4        6 weeks ago         106.7 Mb[[email protected] my. shells]# Docker Pull Nginx  //download nginxusing default tag:latesttrying to pull repository docker.io/library/nginx ... lat Est:pulling from Docker.io/library/nginxe7bb522d92ff:pull complete 6edc05228666:pull complete Cd866a17e81f:pull compl Ete Digest:sha256:285b49d42c703fdf257d1e2422765c4ba9d3e37768d6ea83d7fe2043dad6e63d[[email protected] my. shells]# Docker imagesrepository          TAG                 IMAGE ID            CREATED             sizedocker.io/nginx     latest              3f8a4339aadd        3 weeks ago         108.5 mbdocker.io/redis     latest              1e70071f4af4        6 weeks ago         106.7 MB

2. Run

[[Email protected] my. shells]# Docker run-p 8080:80-d Docker.io/nginx  //80 port is mapped to 8080, or 80:80 or the original 80 port, can not be written. C0462d5e18783e20f9515108fa62ab0f2ac808ea85370a7c82aee9407abf4672[[email protected] My. shells]# NETSTAT-ANP | grep 8080  //port already open tcp6       0      0::: 8080                 :::*                    LISTEN      2529/docker-proxy-c [[email protected] my. shells]# Docker PS  //nginx is already running the container ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                  namesc0462d5e1878        docker.io/nginx     "nginx-g ' daemon Off"   4 minutes ago up       4 minutes        0.0.0.0:8080->80/tcp   Angry_mccarthy

3. Run Results

[[Email protected] my. shells]#./openfirewallport.sh  //First open a port on the fire wall enter the Port:8080success

---openfirewallport.sh-------

echo "Enter the port:"
Read Port
Firewall-cmd--add-port= $port/tcp

has successfully accessed the

Note: When Docker runs Nginx, the outside access is the same IP address as the Docker, which is equivalent to the nginx running on that machine. But for the machine where Docker is located, Nginx is a mirror attached to Docker. If the operation Nginx or Docker login Nginx container, to operate. The login Nginx container is a Linux system, but only Nginx, Nginx installed according to the Linux default path. For example [email protected]:/usr/share/nginx/html# ls This path is the default static page storage path 50x.html  Index.htmlbash commands are the same, but VI in my machine is not available, but can use CP, MV and other commands, because Nginx are configured well, can not be changed.

1) You can write the required files before you log in to the Nignx container, and then copy them to the specified directory:[[email protected] my. shells]# Docker CP hello.html C0462d5e1878://usr/share/nginx/html[[email protected] my. shells]# Docker exec-it c0462d5e1878 bash[email protected]:/usr/share/nginx/html# ls50x.html  hello.html  Index.html
2)

2) mapping to containers via host directory

Docker.io/nginx

-V $PWD/html:usr/share/nginx/html indicates that the current path under the HTML directory is mapped to usr/share/nginx/html

This means that the HTML under the host is the usr/share/nginx/html under the container.

File modifications and additions in HTML are equivalent to container usr/share/nginx/html file operations

Network access can be accessed, you do not have to log into the container operation files

4. Stop Service

[[Email protected] my. shells]# Docker pscontainer ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                  namesc0462d5e1878        Docker.io/nginx     "nginx-g ' daemon off"   minutes ago up,      minutes       0.0.0.0:8080->80/tcp   Angry_mccarthy[[email protected] My. shells]# Docker stop c0462d5e1878 c0462d5e1878[[email protected] my. shells]# Docker pscontainer ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES

5. Restart Service

[[Email protected] my. shells]# Docker pscontainer ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               names[[email protected] My. shells]# Docker start c0462d5e1878 c0462d5e1878[[email protected] my. shells]# Docker pscontainer ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                  namesc0462d5e1878        docker.io/nginx     "nginx-g ' daemon off"   minutes ago up      seconds       0.0.0.0:8080->80/tcp   Angry_mccarthy

6. and start a similar service.

[[Email protected] my. shells]# Docker run-p 8081:80-d Docker.io/nginx//Start a service again, Port is 80811fd8a0b5d138203150f1cdbfb9690235159159881785a4654abb04c7c96c5b18[[email protected] my. shells]# Docker PS//There will be two processes, one 8080, one 8081CONTAINER ID        IMAGE               COMMAND                  CREATED              STATUS              PORTS                  names1fd8a0b5d138        docker.io/nginx     "nginx-g ' daemon Off"   4 seconds ago up        3 seconds        0.0.0.0:8081 ->80/tcp   suspicious_hypatiac0462d5e1878        docker.io/nginx     "nginx-g ' daemon Off" about an   hour Ago up    4 minutes        0.0.0.0:8080->80/tcp   angry_mccarthy

Access to the newly opened 8081 service
Note: The newly started service and the original service are two containers, the original hello.html is not in the new service

7. Uninstall Service

[[email protected] My.             shells]# Docker PS//at this time 8080 and 8081 are running container ID IMAGE COMMAND CREATED STATUS PORTS names1fd8a0b5d138 docker.io/nginx "nginx-g ' daemon off" 4 minute  S ago up 4 minutes 0.0.0.0:8081->80/tcp suspicious_hypatiac0462d5e1878 Docker.io/nginx "Nginx  -G ' daemon off ' about a hour ago up 8 minutes 0.0.0.0:8080->80/tcp angry_mccarthy[[email protected] My. shells]# Docker Stop 1fd8a0b5d138//stop 80811fd8a0b5d138[[email protected] my. shells]# Docker PS//left 8080 still running container ID IMAGE COMMAND CREATED statu S PORTS namesc0462d5e1878 docker.io/nginx "nginx-g ' daemon Off" about an hour ago up 9 minutes 0.0.0.0:8080->80/tcp angry_mccarthy[[email protected] my. shells]# Docker ps-a//Can see 8080 running, 8081 already Exitedcontainer ID       IMAGE COMMAND CREATED STATUS PORTS                          names1fd8a0b5d138 docker.io/nginx "nginx-g ' daemon off" 5 minutes ago Exited (0) 7 seconds ago suspicious_hypatiac0462d5e1878 docker.io/nginx "nginx-g ' daemon off" about a hour ago U P 9 minutes 0.0.0.0:8080->80/tcp angry_mccarthy[[email protected] my. shells]# [[email protected] My. shells]# Docker RM 1fd8a0b5d138//Remove this process is done, note that the process of operation is not RM, first stop1fd8a0b5d138

Category: 4 ways to enter Linux docker containers

After using Docker to create a container, people are more concerned about how to enter the container, in fact, there are several ways to enter the Docker container, here we talk about several common ways to enter the Docker container.

There are several common ways to enter Docker containers:

• Using Docker attach
• Using SSH
• Using Nsenter
• Using the Exec

First, use Docker attach to enter the Docker container

Docker provides the attach command to enter the Docker container.

Next we create a Daemon Docker container and then use the Docker Attach command to enter the container.

1. $ sudo docker run-itd Ubuntu:14.04/bin/bash

We then use Docker PS to view the container information and then use Docker attach to enter the container

1. $ sudo docker attach 44fc0f0582d9

You can see that we have entered the container.

However, there is a problem with using the command. When multiple Windows use the command to enter the container at the same time, all windows are displayed synchronously. If one of the Windows is blocked, other windows can no longer operate.

For this reason, the Docker attach command is not suitable for production environments and can be used when developing your own applications.

Second, use SSH to enter the Docker container

After the use of the Docker attach command to enter the container in the production environment, it is believed that SSH is the first thought of everyone. Install SSH Server in the mirror (or container) so that multiple people can enter

Containers and are not disturbed by each other, I believe you in the current production environment (not using Docker) is also done. However, it is not recommended to use SSH to enter the Docker content after using the Docker container.

Inside the device. Please refer to the following article for the reasons why it is not recommended:

Why don't you need to run sshd in a Docker container

Third, use Nsenter to enter the Docker container

In the case where neither of the above is appropriate, there is a more convenient way to use Nsenter to enter the Docker container. For what is Nsenter please refer to the following article:

Https://github.com/jpetazzo/nsenter

After knowing what Nsenter is, the system defaults to installing the nsenter we need into the host.

If not installed, follow the steps below (note that the host is not a container or mirror)

The specific installation commands are as follows:

1. $ wget https://www.kernel.org/pub/linux/utils/util-linux/v2.24/util-linux-2.24.tar.gz
2. $ TAR-XZVF util-linux-2.24.tar.gz
3. $ CD util-linux-2.24/
4. $./configure--without-ncurses
5. $ make Nsenter
6. $ sudo cp nsenter/usr/local/bin

After installing Nsenter, you can check the use of the command.

Nsenter can access the namespace of another process. So in order to connect to a container we also need to get the PID of the first process of the container. You can use the Docker inspect command to get the PID.

The Docker inspect command is used as follows:

1. $ sudo docker inspect--help

The inspect command displays information for a mirror or container hierarchically. For example, we currently have a running container

You can use Docker inspect to view the details of the container.

1. $ sudo docker inspect 44FC0F0582D9

This information is very much, and only a portion of it is captured here for presentation. If you want to display the first PID of the container, you can use the following method

1. $ sudo docker inspect-f {{. State.pid}} 44fc0f0582d9

After we get the PID of the process, we can use the Nsenter command to access the container.

1. $ sudo nsenter--target 3326--mount--uts--ipc--net--pid

1. $ sudo nsenter--target 3326--mount--uts--ipc--net--pid

3326 of which is the PID of the process just got

Of course, if you think it is too cumbersome to input so many parameters every time, there are many good scripts available on the web for everyone to use.

The address is as follows:

Http://yeasy.gitbooks.io/docker_practice/content/container/enter.html

Http://www.tuicool.com/articles/eYnUBrR

Iv. using Docker exec to enter the Docker container

In addition to the above, Docker provides a new command exec to enter the container after the 1.3.X version, which is relatively simpler, so let's take a look at the use of the command:

1. $ sudo docker exec--help

Next we use this command to enter a container that is already running

1. $ sudo docker PS
2. $ sudo docker exec-it 775c7c9ee1e1/bin/bash

Reference: https://www.cnblogs.com/xhyan/p/6593075.htmlhttps://www.cnblogs.com/wwzyy/p/8337965.html

Docker operation in Centos7