Docker save Command
docker saveThe command is used to save one or more Docker images to a tar archive file for distribution or backup in other environments.
Syntax
docker save [OPTIONS] IMAGE [IMAGE...]
IMAGE: One or more image names or IDs to save.
OPTIONS description:
-o, --output: Specify the path of the output file.
1. Save a single image to a file.
docker save -o myimage.tar myimage:latest
This saves the myimage:latest image as the myimage.tar file.
2. Save multiple images to the same file.
docker save -o multiple_images.tar myimage:latest anotherimage:latest
This saves the myimage:latest and anotherimage:latest images to the multiple_images.tar file.
Example
Build a sample image.
1. Create a Dockerfile:
# 使用 Ubuntu 作为基础镜像 FROM ubuntu:20.04 # 添加维护者信息 LABEL maintainer="yourname@example.com" # 更新包列表并安装 Nginx RUN apt-get update && apt-get install -y nginx # 复制自定义网页到 Nginx 的默认网页目录 COPY index.html /var/www/html/ # 设置启动时的默认命令 CMD ["nginx", "-g", "daemon off;"]
Build image:
docker build -t mynginx:latest .
2. Save the image to a file.
docker save -o mynginx.tar mynginx:latest
This saves the mynginx:latest image as the mynginx.tar file.
3. Verify the saved file.
ls -lh mynginx.tar
Output example:
-rw-r--r-- 1 user user 200M Jul 24 14:00 mynginx.tar
4. Load the saved image.
To load the saved images into another Docker environment, you can use the docker load command:
docker load -i mynginx.tar
Notes
- When saving an image, all layers of the image are included, so the resulting tar file can be very large.
- If saving multiple images to the same file, use
docker loadThe command will load all contained images. - To reduce the file size, you can use the following before saving:
docker image pruneThe command cleans up unused images and layers.
docker saveThe command is a convenient tool for saving Docker images as tar files for backup, distribution, and migration. By combiningdocker loadcommand, you can easily restore and use saved images in different environments.
other extensions