Linux and Docker: How to persist and back up container data?

Linux and Docker: How to perform container data persistence and backup?

With the rapid development of cloud computing and container technology, Docker has become one of the most popular and widely used containerization platforms today. In the process of using Docker for application development and deployment, data persistence and backup is a very important task. This article will introduce how to perform container data persistence and backup in Linux and Docker, and give corresponding code examples.

1. Data persistence

In Docker, the data in the container is stored inside the image by default, which means that when the container is deleted, the data will also be deleted. lost. In order to achieve data persistence, data volumes can be used to associate the data inside the container with the host.

The following is an example of a Dockerfile using a data volume:

FROM ubuntu:latest
VOLUME /data
COPY myapp /data

In this example, we first define a data volume /data, and then # inside the container ##myappThe file is copied to the data volume. In this way, when we run this container, we can access the data in the container by mounting a directory on the host to /data in the container.

Use the following command to run this container and perform data persistence:

$ docker run -v /path/to/host/dir:/data myimage

In the above command,

/path/to/host/dir is on the host A directory that will be mounted into the container at /data. In this way, the data on the host will be synchronized with the data in the container, achieving data persistence.

Data backup

For the data in the container, we usually need to perform regular backups to prevent data loss. In Linux, there are many ways to back up data, such as using the cp command, rsync command, and tar command. The following is an example of using the rsync command for backup:

$ rsync -avz --delete /path/to/source/dir /path/to/backup/dir

In this example, we use the rsync command to synchronize the data in

/path/to/source/dir to /path/to/backup/dir. Among them, the -avz option means performing archive mode, retaining file permissions and recursive backup, and the --delete option means deleting source directory files that do not exist in the backup directory.

In order to achieve automated data backup, we can add the above command to the Cron task. Cron is a service in Linux that is used to perform tasks regularly. You can add scheduled triggers for backup tasks by editing the

/etc/crontab file. The following is a simple example:

# 每天凌晨3点进行数据备份
0 3 * * * root rsync -avz --delete /path/to/source/dir /path/to/backup/dir

In the above example, we set the data backup task to be executed once every day at 3 am.

To sum up, by using data volumes and regular backup methods, we can achieve container data persistence and backup in Linux and Docker. This approach can ensure the reliability and continuity of application data and improve data security and availability.

References:

Docker Documentations. https://docs.docker.com/storage/volumes/
1. Linux Handbook. https://linuxhandbook. com/understand-crontab-syntax/

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