How to modify the internal files of the container

There are three methods for Docker to modify internal files in containers, and the following will be introduced one by one.

1. Enter the container to modify it

Use the following commands to enter the inside of the container to modify the file in the form of a command line.

docker exec-it container ID /bin/bash

However, there is no vim in it, so you need to install it yourself. The installation code is as follows. However, this form is not recommended, because the files inside are temporary. After the container is deleted, the configuration will be invalid and need to be configured again.

apt-get update
apt-get install vim

2. Modify through docker cp copy

You can copy the file that needs to be modified through the following code, and then copy it back after the modification is completed. This method is actually similar to the first one, except that you don’t need to install vim, but after the container is deleted, the modified content will also become invalid. And the container needs to be restarted to take effect (it seems to be)

#Copy the files in the container
sudo docker cpContainer ID:/etc/mysql/ /home/tom/#Copy the files in the container back
sudo docker cp/home/tom/ Container ID:/etc/mysql/

3. Use -v to mount the folder (recommended)

The last method is to use -v to mount (map) the folder inside the container to a local path when starting. In the future, you can directly modify it locally without entering the container.

#Before the colon, the local path (absolute path is required), and after the colon, the path in the container
$ docker run --name mytomcat -v /home/www/webapps:/usr/local/tomcat/webapps -d tomcat