目錄
- 一、docker-squash 安裝
- 二、使用介紹
- 2.1、部分壓縮指定層數
- 2.2、完全壓縮
- 三、總結
- 參考文檔
docker build 通過Dockerfile 制作鏡像會根據命令形成一層層layer,這樣造成文件重復，鏡像體積比較大；為了縮小層的數量及其大小，能夠像壓縮git commit一樣壓縮layer層，docker-squash能夠執行此操作。Docker squash將壓縮多個鏡像layer層，以便刪除存儲在兩頭步驟中的所有數據，即刪除掉重復數據。本文就docker-squash 使用效果展開討論。
一、docker-squash 安裝
pip install docker-squash
docker-squash --help usage: docker-squash [-h] [-v] [--version] [-d] [-f FROM_LAYER] [-t TAG] ? ? ? ? ? ? ? ? ? ? ?[-m MESSAGE] [-c] [--tmp-dir TMP_DIR] ? ? ? ? ? ? ? ? ? ? ?[--output-path OUTPUT_PATH] ? ? ? ? ? ? ? ? ? ? ?image Docker layer squashing tool positional arguments: ? image ? ? ? ? ? ? ? ? Image to be squashed optional arguments: ? -h, --help ? ? ? ? ? ?show this help message and exit ? -v, --verbose ? ? ? ? Verbose output ? --version ? ? ? ? ? ? Show version and exit ? -d, --development ? ? Does not clean up after failure for easier debugging ? -f FROM_LAYER, --from-layer FROM_LAYER ? ? ? ? ? ? ? ? ? ? ? ? Number of layers to squash or ID of the layer (or ? ? ? ? ? ? ? ? ? ? ? ? image ID or image name) to squash from. In case the ? ? ? ? ? ? ? ? ? ? ? ? provided value is an integer, specified number of ? ? ? ? ? ? ? ? ? ? ? ? layers will be squashed. Every layer in the image will ? ? ? ? ? ? ? ? ? ? ? ? be squashed if the parameter is not provided. ? -t TAG, --tag TAG ? ? Specify the tag to be used for the new image. If not ? ? ? ? ? ? ? ? ? ? ? ? specified no tag will be applied ? -m MESSAGE, --message MESSAGE ? ? ? ? ? ? ? ? ? ? ? ? Specify a commit message (comment) for the new image. ? -c, --cleanup ? ? ? ? Remove source image from Docker after squashing ? --tmp-dir TMP_DIR ? ? Temporary directory to be created and used ? --output-path OUTPUT_PATH ? ? ? ? ? ? ? ? ? ? ? ? Path where the image should be stored after squashing. ? ? ? ? ? ? ? ? ? ? ? ? If not provided, image will be loaded into Docker ? ? ? ? ? ? ? ? ? ? ? ? daemon
二、使用介紹
2.1、部分壓縮指定層數
首先docker history查看鏡像層數
docker history java:3.0 IMAGE CREATED CREATED BY SIZE COMMENT 63a1b1edb376 4 weeks ago /bin/sh -c #(nop) LABEL ImageName=reg.docke… 0B <missing> 4 weeks ago /bin/sh -c #(nop) LABEL BaseRootfsLayerCoun… 0B <missing> 4 weeks ago /bin/sh -c #(nop) LABEL BaseLayerCount=25 0B <missing> 4 weeks ago /bin/sh -c #(nop) LABEL baseOS=reg.docker.a… 0B <missing> 4 weeks ago /bin/sh -c #(nop) VOLUME [/home/admin/logs] 0B <missing> 4 weeks ago /bin/sh -c #(nop) ENTRYPOINT ["/bin/sh" "-c… 0B <missing> 4 weeks ago /bin/sh -c #(nop) ENV JVM_Xms= JVM_Xmx= JVM… 0B <missing> 4 weeks ago /bin/sh -c #(nop) ENV JAVA_HOME=/opt/taobao… 0B <missing> 4 weeks ago /bin/sh -c #(nop) ENV LANG=zh_CN.utf8 0B <missing> 4 weeks ago /bin/sh -c [[ $(uname -p) != "sw_64" ]] && r… 97MB <missing> 4 weeks ago /bin/sh -c yum clean --enablerepo=* all; … 628MB <missing> 4 weeks ago /bin/sh -c #(nop) COPY file:cbad11e2b6b88c38… 19.9MB <missing> 4 weeks ago /bin/sh -c #(nop) COPY file:fd3bca1e9167d639… 21MB <missing> 4 weeks ago /bin/sh -c #(nop) COPY dir:2761dc242787e3ab8… 39.2MB <missing> 4 weeks ago /bin/sh -c #(nop) COPY dir:8a9faa49606db326b… 8.49MB <missing> 4 weeks ago /bin/sh -c #(nop) LABEL ImageName=reg.docke… 0B <missing> 4 weeks ago /bin/sh -c #(nop) LABEL BaseRootfsLayerCoun… 0B <missing> 4 weeks ago /bin/sh -c #(nop) LABEL BaseLayerCount=10 0B <missing> 4 weeks ago /bin/sh -c #(nop) LABEL baseOS=reg.docker.a… 0B <missing> 4 weeks ago /bin/sh -c #(nop) ENTRYPOINT [""] 0B <missing> 4 weeks ago /bin/sh -c #(nop) CMD ["/sbin/init"] 0B <missing> 4 weeks ago /bin/sh -c #(nop) COPY dir:61a850de6501dac7b… 3.03kB <missing> 4 weeks ago /bin/sh -c sed -i -e 's/root:[^:]*:/root:*:/… 94.6MB <missing> 4 weeks ago /bin/sh -c #(nop) COPY dir:ca4e72cff3459ccab… 395B <missing> 16 months ago 282MB Imported from -
使用dive 工具查看鏡像效率參數
CI=true dive java:3.0
Using default CI config
Image Source: docker://java:3.0
Fetching image... (this can take a while for large images)
Analyzing image...
efficiency: 78.5919 %
UserSizeByes: 90775433100 bytes (908 MB)
SizeByes: 118928447300 bytes (1.2 GB)
wastedBytes: 381696817 bytes (382 MB)
userWastedPercent: 42.0485 %
Inefficient Files:
Count Wasted Space File Path
2 119 MB /usr/lib/locale/locale-archive
...
2 0 B /usr/lib/systemd/system/runlevel0.target
Results:
FAIL: highestUserWastedPercent: too many bytes wasted, relative to the user bytes added (%-user-wasted-bytes=0.4204847104166557 > threshold=0.1)
SKIP: highestWastedBytes: rule disabled
FAIL: lowestEfficiency: image efficiency is too low (efficiency=0.7859187397531037 < threshold=0.9)
Result:FAIL [Total:3] [Passed:0] [Failed:2] [Warn:0] [Skipped:1
命令格式
docker-squash -f <層數，依據docker history> -t 新鏡像名稱 原鏡像名稱
如下：
docker-squash -f 11 -t java-squash-11:1.0 java:3.0 2023-01-20 13:41:43,978 root INFO docker-squash version 1.0.10, Docker 5138787, API 1.39... 2023-01-20 13:41:43,978 root INFO Using v2 image format 2023-01-20 13:41:43,982 root INFO Old image has 25 layers 2023-01-20 13:41:43,982 root INFO Checking if squashing is necessary... 2023-01-20 13:41:43,982 root INFO Attempting to squash last 11 layers... 2023-01-20 13:41:43,982 root INFO Saving image sha256:63a1b1edb376fb12838dbbef7749effc1e8e6a973d33a47aee194eff6a173edd to /tmp/docker-squash-OlTnlF/old directory... 2023-01-20 13:42:03,134 root INFO Image saved! 2023-01-20 13:42:03,135 root INFO Squashing image 'java:3.0'... 2023-01-20 13:42:03,136 root INFO Starting squashing... 2023-01-20 13:42:03,870 root INFO Squashing file '/tmp/docker-squash-OlTnlF/old/ddf4a6e4ea15a7ca3825c70e116e40f3a01f25b7df008d4517c826ef78c03dc8/layer.tar'... 2023-01-20 13:42:06,729 root INFO Squashing file '/tmp/docker-squash-OlTnlF/old/7be6dcb4742458db7e2c77fb1ad9fd66555e6f08d28c74592a9b973740356919/layer.tar'... 2023-01-20 13:42:19,510 root INFO Squashing finished! 2023-01-20 13:42:22,736 root INFO Original image size: 1166.43 MB 2023-01-20 13:42:22,736 root INFO Squashed image size: 1153.64 MB 2023-01-20 13:42:22,736 root INFO Image size decreased by 1.10 % 2023-01-20 13:42:22,736 root INFO New squashed image ID is 794121cd589230285a51d969aac97c5e936d732b0feefe5c05e78b027e850312 2023-01-20 13:42:30,244 root INFO Image registered in Docker daemon as java-squash-11:1.0 2023-01-20 13:42:30,369 root INFO Done
壓縮后體積如下：
docker images | grep java java-squash-11 1.0 794121cd5892 About a minute ago 1.17GB java 3.0 63a1b1edb376 4 weeks ago 1.19GB
再次查看history
docker history java-squash-11:1.0 IMAGE CREATED CREATED BY SIZE COMMENT 794121cd5892 5 minutes ago 703MB <missing> 4 weeks ago /bin/sh -c #(nop) COPY file:cbad11e2b6b88c38… 19.9MB <missing> 4 weeks ago /bin/sh -c #(nop) COPY file:fd3bca1e9167d639… 21MB <missing> 4 weeks ago /bin/sh -c #(nop) COPY dir:2761dc242787e3ab8… 39.2MB <missing> 4 weeks ago /bin/sh -c #(nop) COPY dir:8a9faa49606db326b… 8.49MB <missing> 4 weeks ago /bin/sh -c #(nop) LABEL ImageName=reg.docke… 0B <missing> 4 weeks ago /bin/sh -c #(nop) LABEL BaseRootfsLayerCoun… 0B <missing> 4 weeks ago /bin/sh -c #(nop) LABEL BaseLayerCount=10 0B <missing> 4 weeks ago /bin/sh -c #(nop) LABEL baseOS=reg.docker.a… 0B <missing> 4 weeks ago /bin/sh -c #(nop) ENTRYPOINT [""] 0B <missing> 4 weeks ago /bin/sh -c #(nop) CMD ["/sbin/init"] 0B <missing> 4 weeks ago /bin/sh -c #(nop) COPY dir:61a850de6501dac7b… 3.03kB <missing> 4 weeks ago /bin/sh -c sed -i -e 's/root:[^:]*:/root:*:/… 94.6MB <missing> 4 weeks ago /bin/sh -c #(nop) COPY dir:ca4e72cff3459ccab… 395B <missing> 16 months ago 282MB Imported from -
再次dive 分析,鏡像效率參數有些許改觀
CI=true dive java-squash-11:1.0
Using default CI config
Image Source: docker://java-squash-11:1.0
Fetching image... (this can take a while for large images)
Analyzing image...
efficiency: 79.9717 %
UserSizeByes: 88655803400 bytes (887 MB)
SizeByes: 116808817600 bytes (1.2 GB)
wastedBytes: 360500520 bytes (360 MB)
userWastedPercent: 40.6629 %
Inefficient Files:
Count Wasted Space File Path
2 119 MB /usr/lib/locale/locale-archive
...
2 0 B /usr/lib/systemd/system/sysinit.target.wants/cryptsetup.target
Results:
FAIL: highestUserWastedPercent: too many bytes wasted, relative to the user bytes added (%-user-wasted-bytes=0.40662935326803434 > threshold=0.1)
SKIP: highestWastedBytes: rule disabled
FAIL: lowestEfficiency: image efficiency is too low (efficiency=0.7997167019774828 < threshold=0.9)
Result:FAIL [Total:3] [Passed:0] [Failed:2] [Warn:0] [Skipped:1]
2.2、完全壓縮
即壓縮成一層
docker-squash -f 25 -t java-squash-all:1.0 java:3.0 2023-01-20 13:53:47,397 root INFO docker-squash version 1.0.10, Docker 5138787, API 1.39... 2023-01-20 13:53:47,397 root INFO Using v2 image format 2023-01-20 13:53:47,401 root INFO Old image has 25 layers 2023-01-20 13:53:47,401 root INFO Checking if squashing is necessary... 2023-01-20 13:53:47,401 root INFO Attempting to squash last 25 layers... 2023-01-20 13:53:47,401 root INFO Saving image sha256:63a1b1edb376fb12838dbbef7749effc1e8e6a973d33a47aee194eff6a173edd to /tmp/docker-squash-23fgk8/old directory... 2023-01-20 13:54:06,767 root INFO Image saved! 2023-01-20 13:54:06,767 root INFO Squashing image 'java:3.0'... 2023-01-20 13:54:06,768 root INFO Starting squashing... 2023-01-20 13:54:06,768 root INFO Squashing file '/tmp/docker-squash-23fgk8/old/ddf4a6e4ea15a7ca3825c70e116e40f3a01f25b7df008d4517c826ef78c03dc8/layer.tar'... 2023-01-20 13:54:09,616 root INFO Squashing file '/tmp/docker-squash-23fgk8/old/7be6dcb4742458db7e2c77fb1ad9fd66555e6f08d28c74592a9b973740356919/layer.tar'... 2023-01-20 13:54:20,751 root INFO Squashing file '/tmp/docker-squash-23fgk8/old/57be802a5ecce1545d1fef09e3f0b04cef12386e3995b8f98b827c1fa690f2dc/layer.tar'... 2023-01-20 13:54:20,778 root INFO Squashing file '/tmp/docker-squash-23fgk8/old/e113fadd42d1969d71a6d30cf402938436e9aba0de9af3ed2cdacec9e1842103/layer.tar'... 2023-01-20 13:54:20,799 root INFO Squashing file '/tmp/docker-squash-23fgk8/old/eca237f8359a3c25227be27fd27ebff05b510f06b9768639e3484741d9995073/layer.tar'... 2023-01-20 13:54:20,809 root INFO Squashing file '/tmp/docker-squash-23fgk8/old/2a47dbd3a252894e057a55d676f92625d24bfc8ad10a28b008e8b87638480ee6/layer.tar'... 2023-01-20 13:54:20,871 root INFO Squashing file '/tmp/docker-squash-23fgk8/old/bb207541a62d1cf5aa5dc13e971301949a22d2c3016e317d2190f1b51bde0167/layer.tar'... 2023-01-20 13:54:20,876 root INFO Squashing file '/tmp/docker-squash-23fgk8/old/354eb0981c6f10dcf5744386501d61c670f5bfbf77063c778b26e5c0450543f3/layer.tar'... 2023-01-20 13:54:22,489 root INFO Squashing file '/tmp/docker-squash-23fgk8/old/e31074992543d56a24b7da3457af34c7df7439ced6d9c0bf72ce4122fc380d81/layer.tar'... 2023-01-20 13:54:22,492 root INFO Squashing file '/tmp/docker-squash-23fgk8/old/1641651324846664fa3c233e4459767551e4ab9f081a718085216d30687e0877/layer.tar'... 2023-01-20 13:54:52,084 root INFO Squashing finished! 2023-01-20 13:54:54,922 root INFO Original image size: 1166.43 MB 2023-01-20 13:54:54,922 root INFO Squashed image size: 981.28 MB 2023-01-20 13:54:54,922 root INFO Image size decreased by 15.87 % 2023-01-20 13:54:54,923 root INFO New squashed image ID is f508f38322ae8950e49bd8cbcf140356dd236654ecd6bf303440d93081f6f7c9 2023-01-20 13:55:04,532 root INFO Image registered in Docker daemon as java-squash-all:1.0 2023-01-20 13:55:04,624 root INFO Done
docker history 查看
docker history java-squash-all:1.0 IMAGE CREATED CREATED BY SIZE COMMENT f508f38322ae About a minute ago 989MB
docker images 比較一下大小
docker images | grep java java-squash-all 1.0 f508f38322ae 30 minutes ago 989MB java-squash-11 1.0 794121cd5892 42 minutes ago 1.17GB java 3.0 63a1b1edb376 4 weeks ago 1.19GB
dive 分析
CI=true dive java-squash-all:1.0 Using default CI config Image Source: docker://java-squash-all:1.0 Fetching image... (this can take a while for large images) Analyzing image... efficiency: 100.0000 % UserSizeByes: 0 bytes (0 B) SizeByes: 98904607400 bytes (989 MB) wastedBytes: 0 bytes (0 B) userWastedPercent: NaN % Inefficient Files: Count Wasted Space File Path None Results: PASS: highestUserWastedPercent SKIP: highestWastedBytes: rule disabled PASS: lowestEfficiency Result:PASS [Total:3] [Passed:2] [Failed:0] [Warn:0] [Skipped:1]
三、總結
1、docker-squash 根據docker history 層數對鏡像進行壓縮
2、-f 指定的層數越大，壓縮效率越好
3、結合dive 工具，更直觀展示壓縮效率
4、壓縮后的圖像可以加載回Docker守護進程，即可以通過docker images 查看
5、使用docker-squash 也存在缺點，壓縮為一層時無法根據docker history查看鏡像構建歷史。
參考文檔
1、https://lequ7.com/guan-yu-docker-chuang-jian-zui-xiao-hua-de-rong-qi-jing-xiang-er.html
2、https://mp.weixin.qq.com/s/S1Ib08SpQbf1SCbCutUoqQ
3、https://blog.csdn.net/j_starry/article/details/125185506
4、https://github.com/jwilder/docker-squash
5、https://bbs.huaweicloud.com/blogs/336684
6、https://github.com/dive/
7、https://www.cnpython.com/pypi/docker-squash
8、https://cloud.tencent.com/developer/article/1444954
