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| docker-squash | ||
| ============= | ||
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| Squash docker images to make them smaller | ||
| Squash docker images to make them smaller. | ||
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| Status: Experimental | ||
| docker-squash is a utility to squash multiple docker layers into one in order to create an image | ||
| with fewer layers as well as smaller ones. It retains Dockerfile commands such as PORT, | ||
| ENV, etc.. so that squash images work the same as they were originally built. In addition, deleted | ||
| files in layer layers are actually purged from the image when squashed. | ||
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| It's designed to support a workflow where you would squash the image just before pushing it | ||
| to a registry. Before squashing the image, you would remove any build time dependencies, extra | ||
| files (apt caches, logs, private keys, etc..) that you would not want to deploy. The defaults also | ||
| preseve your base image so that it's contents are not repeatedly transferred when pushing and pulling | ||
| images. | ||
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| Typical workflow is: | ||
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| * Build image from Dockerfile (or other) | ||
| * Run clean up commands in container (apt-get purge, rm /path, etc..) | ||
| * Commit container | ||
| * Squash the image | ||
| * Push squashed image to registry | ||
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| See [Squashing Docker Images](http://jasonwilder.com/blog/2014/08/19/squashing-docker-images/) | ||
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| ## Sample Output | ||
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| ``` | ||
| $ docker save 49b5a7a88d5 | sudo docker-squash -t squash -verbose | docker load | ||
| Loading export from STDIN using /tmp/docker-squash683466637 for tempdir | ||
| Loaded image w/ 15 layers | ||
| Extracting layers... | ||
| - /tmp/docker-squash683466637/49b5a7a88d5353fe77204ad5591a3ef100fc2807a9d6dce979fd1b17a73a68d6/layer.tar | ||
| - /tmp/docker-squash683466637/651626d6e364ccc22ac990ba95cd0aab9256c56055087cc9a5a1790cea5250b9/layer.tar | ||
| - /tmp/docker-squash683466637/c50f2b65cab3b74f9bdb6f616b36f132b9a182ed883d03f11173e32fa39ab599/layer.tar | ||
| - /tmp/docker-squash683466637/d92c3c92fa73ba974eb409217bb86d8317b0727f42b73ef5a05153b729aaf96b/layer.tar | ||
| - /tmp/docker-squash683466637/511136ea3c5a64f264b78b5433614aec563103b4d4702f3ba7d4d2698e22c158/layer.tar | ||
| - /tmp/docker-squash683466637/1c9383292a8ff4c4196ff4ffa36e5ff24cb217606a8d1f471f4ad27c4690e290/layer.tar | ||
| - /tmp/docker-squash683466637/589338fba5eb5cc32a25a036975a5e0938f12eff0dc70b661363c13ef1a192a5/layer.tar | ||
| - /tmp/docker-squash683466637/63e174c2ca3d53e2b7639a440940e16e15c1970e6ad16f740ffdcc60e59e0324/layer.tar | ||
| - /tmp/docker-squash683466637/9942dd43ff211ba917d03637006a83934e847c003bef900e4808be8021dca7bd/layer.tar | ||
| - /tmp/docker-squash683466637/0ea0d582fd9027540c1f50c7f0149b237ed483d2b95ac8d107f9db5a912b4240/layer.tar | ||
| - /tmp/docker-squash683466637/8dfc0bb00563dab615dfcc28ab3e338089f5b1d71d82d731c18cbe9f7667435f/layer.tar | ||
| - /tmp/docker-squash683466637/c4ff7513909dedf4ddf3a450aea68cd817c42e698ebccf54755973576525c416/layer.tar | ||
| - /tmp/docker-squash683466637/cc58e55aa5a53b572f3b9009eb07e50989553b95a1545a27dcec830939892dba/layer.tar | ||
| - /tmp/docker-squash683466637/e4eea4411c0065f8b0c7cf6be31dd58daa5ac04d8c64d54537cbfce2eb8e3413/layer.tar | ||
| - /tmp/docker-squash683466637/fc294d2b22cb53cb2440ff6fece18813ee7363f5198f5e20346abfcf7cce54fe/layer.tar | ||
| Inserted new layer 27935276f797 after 1c9383292a8f | ||
| - 511136ea3c5a | ||
| - 1c9383292a8f /bin/sh -c #(nop) ADD file:c1472c26527df28498744f9e9e8a8304c | ||
| -> 27935276f797 /bin/sh -c #(squash) from 1c9383292a8f | ||
| - 9942dd43ff21 /bin/sh -c echo '#!/bin/sh' > /usr/sbin/policy-rc.d && echo | ||
| - d92c3c92fa73 /bin/sh -c rm -rf /var/lib/apt/lists/* | ||
| - 0ea0d582fd90 /bin/sh -c sed -i 's/^#\s*\(deb.*universe\)$/\1/g' /etc/apt/ | ||
| - cc58e55aa5a5 /bin/sh -c apt-get update && apt-get dist-upgrade -y && rm - | ||
| - c4ff7513909d /bin/sh -c #(nop) CMD [/bin/bash] | ||
| - fc294d2b22cb /bin/sh -c apt-get update && apt-get install -y golang-go | ||
| - 8dfc0bb00563 /bin/sh -c #(nop) ADD dir:78239d85b32dd28e4cb1d81ace7ffd32b8 | ||
| - 651626d6e364 /bin/sh -c #(nop) WORKDIR /app | ||
| - 589338fba5eb /bin/sh -c go build -o http | ||
| - c50f2b65cab3 /bin/sh -c #(nop) ENV PORT=8000 | ||
| - e4eea4411c00 /bin/sh -c #(nop) EXPOSE map[8000/tcp:{}] | ||
| - 63e174c2ca3d /bin/sh -c #(nop) CMD [/app/http] | ||
| - 49b5a7a88d53 /bin/bash | ||
| Squashing from 27935276f797 into 27935276f797 | ||
| - Deleting whiteouts | ||
| - Rewriting child history | ||
| - Removing 9942dd43ff21. Squashed. (/bin/sh -c echo '#!/bin/sh' > /usr/sbin/policy-...) | ||
| - Removing d92c3c92fa73. Squashed. (/bin/sh -c rm -rf /var/lib/apt/lists/*) | ||
| - Removing 0ea0d582fd90. Squashed. (/bin/sh -c sed -i 's/^#\s*\(deb.*universe\)$/\1...) | ||
| - Removing cc58e55aa5a5. Squashed. (/bin/sh -c apt-get update && apt-get dist-upgra...) | ||
| - Replacing c4ff7513909d w/ new layer 72391e640b52 (/bin/sh -c #(nop) CMD [/bin/bash]) | ||
| - Removing fc294d2b22cb. Squashed. (/bin/sh -c apt-get update && apt-get install -y...) | ||
| - Removing 8dfc0bb00563. Squashed. (/bin/sh -c #(nop) ADD dir:78239d85b32dd28e4cb1d...) | ||
| - Replacing 651626d6e364 w/ new layer bd7b4b11874a (/bin/sh -c #(nop) WORKDIR /app) | ||
| - Removing 589338fba5eb. Squashed. (/bin/sh -c go build -o http) | ||
| - Replacing c50f2b65cab3 w/ new layer e4af8871b961 (/bin/sh -c #(nop) ENV PORT=8000) | ||
| - Replacing e4eea4411c00 w/ new layer 6803497b6a61 (/bin/sh -c #(nop) EXPOSE map[8000/tcp:{}]) | ||
| - Replacing 63e174c2ca3d w/ new layer 40b8c7c33bba (/bin/sh -c #(nop) CMD [/app/http]) | ||
| - Removing 49b5a7a88d53. Squashed. (/bin/bash) | ||
| Tarring up squashed layer 27935276f797 | ||
| Removing extracted layers | ||
| Tagging 40b8c7c33bba as jwilder/whoami:squash | ||
| Tarring new image to STDOUT | ||
| Done. New image created. | ||
| - 40b8c7c33bba Less than a second /bin/sh -c #(nop) CMD [/app/http] 3.072 kB | ||
| - 6803497b6a61 Less than a second /bin/sh -c #(nop) EXPOSE map[8000/tcp:{}] 3.072 kB | ||
| - e4af8871b961 Less than a second /bin/sh -c #(nop) ENV PORT=8000 3.072 kB | ||
| - bd7b4b11874a Less than a second /bin/sh -c #(nop) WORKDIR /app 3.072 kB | ||
| - 72391e640b52 Less than a second /bin/sh -c #(nop) CMD [/bin/bash] 3.072 kB | ||
| - 27935276f797 1 seconds /bin/sh -c #(squash) from 1c9383292a8f 39.49 MB | ||
| - 1c9383292a8f 3 days /bin/sh -c #(nop) ADD file:c1472c26527df28498744f9e9e8a83... 201.6 MB | ||
| - 511136ea3c5a 14 months 1.536 kB | ||
| Removing tempdir /tmp/docker-squash683466637 | ||
| ``` | ||
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| ## Installation | ||
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| Download the latest version: | ||
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| * [linux/amd64](https://github.com/jwilder/docker-squash/releases/download/v0.0.7/docker-sqush-linux-amd64-v0.0.7.tar.gz) | ||
| * OSX currently not tested. | ||
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| ``` | ||
| $ wget https://github.com/jwilder/docker-squash/releases/download/v0.0.7/docker-squash-linux-amd64-v0.0.7.tar.gz | ||
| $ sudo tar -C /usr/local/bin -xzvf docker-gen-linux-amd64-v0.0.7.tar.gz | ||
| ``` | ||
| NOTE: docker-squash must run as root (to maintain file permission created within images). | ||
|
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| ## Usage | ||
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| docker-squash works by squashing a saved image and loading the squashed image back into docker. | ||
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| $ docker save <image id> > image.tar | ||
| $ sudo docker-squash -i image.tar -o squashed.tar | ||
| $ cat squashed.tar | docker load | ||
| $ docker images <new image id> | ||
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| You can also tag the squashed image: | ||
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| $ docker save <image id> > image.tar | ||
| $ sudo docker-squash -i image.tar -o squashed.tar -t newtag | ||
| $ cat squashed.tar | docker load | ||
| $ docker images <new image id> | ||
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| You can reduce disk IO by piping the input and output to and from docker: | ||
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| $ docker save <image id> | sudo docker-squash -t newtag | docker load | ||
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| If you have a sufficient amount of RAM, you can also use a `tmpfs` to remove temporary | ||
| disk storage: | ||
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| $ docker save <image_id> | sudo TMPDIR=/var/run/shm docker-squash -t newtag | docker load | ||
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| By default, a squashed layer is inserted after the first `FROM` layer. You can specify a differnt | ||
| layer with the `-from` argument. | ||
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| $ docker save <image_id> | sudo docker-squash -from <other layer> -t newtag | docker load | ||
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| If you are creating a base image or only want one final squashed layer, you can use the | ||
| `-from root` to squash the base layer and your changes into one layer. | ||
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| $ docker save <image_id> | sudo docker-squash -from root -t newtag | docker load | ||
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| ## License | ||
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| MIT |