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Haskell Web Server in a 5MB Docker Image (fpcomplete.com)
65 points by lubomir 4059 days ago
4 comments
cies 4058 days ago
I was looking into some of this myself already; really helpful article and amazing results. Another interesting approach is to compile Haskell with HaLVM[1] in to a unikernel that can run on a Xen hypervisor. But this is a non-posix environment on which Haskell's "network" package does not compile. No "network" means that it is currently impossible[2] for WAI (Haskell's standard interface between web servers and applications), but also db libraries, to run in such an environment.

With going unikernel with Haskell still being a little steep (but definitely on my wish list), then the next-best would be a mini VM/container image. And 5MB sure is mini!

Once again, thanks FPComplete!

1: https://github.com/GaloisInc/HaLVM

2: https://github.com/GaloisInc/HaLVM/issues/43

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tel 4058 days ago
OCaml's Mirage unikernel seems to have a lot of steam these days.
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cies 4058 days ago
Yeah it's a very complete project. And we saw "Look Ma No OS"[1] today on HN about Erlang/Elixir-on-Xen with the LING unikernel. But it is Haskell that I'm personally all hyped up about lately; and OS-less-ness is to me merely a potential secondary advantage of going back to "compiled" (I come from Ruby/Python before that Java before that C++).

My main reason for going with Haskell is that I know the costs of bugs, and feel that I get to old for fighting bugs on tight deadlines.

1: http://slides.com/technolo-g/intro-to-unikernels-and-erlang-...

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tel 4058 days ago
Well, I'd suggest that OCaml probably has similar bug fighting properties as Haskell. It depends a lot on how much you enjoy writing module existence proofs :)

If I had any genuine reason for a unikernel today I'd definitely go for Mirage.

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chanux 4058 days ago
I was once fascinated by tiny docker images and wanted to have a tiny docker image with a web server.

There was a go web server I dockerized and came under 5MB [1]. But the thttpd image by larsks was an amazing 1MB [2].

[1] https://registry.hub.docker.com/u/chanux/muhttpd/

[2] https://registry.hub.docker.com/u/larsks/thttpd/

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joeyh 4058 days ago
I use the same technique of bundling the necessary dynamic libraries and gconv files for the git-annex standalone tarball distribution. I've observed users untarring that onto arbitrary wacky NAS boxes and it just working, which is pretty nice.

I later adapted that for use in propellor too, when it's deploying docker/etc containers. This allows propellor to bootstrap itself to run inside an arbitrary docker container. http://joeyh.name/blog/entry/propelling_containers/

Later, I used propellor's ability to bootstrap itself this way to let it copy itself onto a VM and run there to replace its content with a clean reinstall of Debian. http://joeyh.name/blog/entry/clean_OS_reinstalls_with_propel...

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thu 4058 days ago
Oh I was following the same path and was mising a library or two. The result is similar to Michael's scratch image: https://gist.github.com/noteed/4155ffad2b1d13ab17ee

The resulting image for "hello world" compressed with `xz` (default options) is 1.5MB. And it runs in a chroot or with qemu too.

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