# Speed up dockerization
**URL:** https://discourse.julialang.org/t/speed-up-dockerization/135971
**Category:** General Usage
**Tags:** docker, package-compiler
**Created:** [March 2, 2026, 6:39pm UTC](https://discourse.julialang.org/t/speed-up-dockerization/135971 "2026-03-02T18:39:18Z")
**Posts on this page:** 9
**Page:** 1
### Author:  [@ohmsweetohm1](https://discourse.julialang.org/u/ohmsweetohm1)
#### Post date: [March 2, 2026, 6:39pm UTC](https://discourse.julialang.org/t/speed-up-dockerization/135971/1 "2026-03-02T18:39:18Z")
I am deploying Julia code using docker. In order to speed up the startup of the container I build a package using PackageCompiler.jl.
However this is painfully slow, as it rebuilds everything even if I change one line in the final main entrypoint. Are there any best practices to speed this up? How could I build a sysimage with just the packages and do not precompile my application code? Do I just make a sysimage in a `builder` stage and copy it over into the the final output stage of the image, together with the main application source code?
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### Author:  [@jishnub](https://discourse.julialang.org/u/jishnub)
#### Post date: [March 2, 2026, 7:21pm UTC](https://discourse.julialang.org/t/speed-up-dockerization/135971/2 "2026-03-02T19:21:09Z")
I went with a persistent build cache that stores the precompiled package images so that the dependencies don’t need to be recompiled every time. I followed [this post.](https://discourse.julialang.org/t/proposed-julia-docker-workflow-to-use-a-persistent-depot/97963)
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### Author:  [@ohmsweetohm1](https://discourse.julialang.org/u/ohmsweetohm1)
#### Post date: [March 2, 2026, 8:22pm UTC](https://discourse.julialang.org/t/speed-up-dockerization/135971/3 "2026-03-02T20:22:11Z")
Is the source code of the packages still in the image? I cannot have that for some private packages.
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### Author:  [@jishnub](https://discourse.julialang.org/u/jishnub)
#### Post date: [March 3, 2026, 11:02am UTC](https://discourse.julialang.org/t/speed-up-dockerization/135971/4 "2026-03-03T11:02:49Z")
Oh, I see. In our case that wasn’t a restriction, and the source code is indeed present in the image.
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### Author:  [@ohmsweetohm1](https://discourse.julialang.org/u/ohmsweetohm1)
#### Post date: [March 3, 2026, 11:20am UTC](https://discourse.julialang.org/t/speed-up-dockerization/135971/5 "2026-03-03T11:20:12Z")
If I do not need to copy the whole `.julia` this might be possible.
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### Author:  [@greatpet](https://discourse.julialang.org/u/greatpet)
#### Post date: [March 3, 2026, 11:21am UTC](https://discourse.julialang.org/t/speed-up-dockerization/135971/6 "2026-03-03T11:21:12Z")
In my limited experience, PrecompileTools.jl can usually make the load time fast enough, so I don’t resort to PackageCompiler, considering that there’s also a startup delay in launching any Docker container. (To clarify, the precompile process is added as a build step for the Docker image.)
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### Author:  [@ohmsweetohm1](https://discourse.julialang.org/u/ohmsweetohm1)
#### Post date: [March 3, 2026, 4:23pm UTC](https://discourse.julialang.org/t/speed-up-dockerization/135971/7 "2026-03-03T16:23:14Z")
Also nice. What part of the JULIA\_DEPOT\_PATH do I need to copy over from the builder stage?
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### Author:  [@greatpet](https://discourse.julialang.org/u/greatpet)
#### Post date: [March 3, 2026, 7:05pm UTC](https://discourse.julialang.org/t/speed-up-dockerization/135971/8 "2026-03-03T19:05:10Z")
Sorry, I meant just as a step in Dockerfile, not in a separate builder image. If you run “Pkg.precompile()” in the Dockerfile, then the precompile cache is saved.
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### Author:  [@ohmsweetohm1](https://discourse.julialang.org/u/ohmsweetohm1)
#### Post date: [March 3, 2026, 9:52pm UTC](https://discourse.julialang.org/t/speed-up-dockerization/135971/9 "2026-03-03T21:52:28Z")
I understood that, but I do not want to copy everything. As I wrote earlier I specifically do not want the source code in the final image.