Cross Compiling Static Rust Binaries for Linux on OS X


Recently I wrote a small Rust executable for work. I wrote it on my Apple laptop, but wanted to run it on our Linux servers. This note hopes to document how I did it so that I and others may repeat my experience.

Note: I only managed to pull this off because of the helpful folks on the #rust and #rust-internals IRC channels. Thanks everyone!

Set up

There are plenty of tutorials out there for getting started with Rust, though it’s tough to beat the official book. In order to get a working environment going, I recommend using rustup.

First, create a new binary project with cargo:

cargo init --bin my_proj
cd my_proj

In order to get stuff working later, use the nightly branch of Rust:

rustup override set nightly

Write your project as usual, editing src/ to your heart’s content.


In order to get your executable to run on the Linux server, you’ll need to compile & link it for that platform. I’ve had luck creating an entirely static executable using musl, a rewrite of the C standard library intended for smaller, embedded targets. To get the necessary tools installed on OS X, use homebrew with this helpful tap.

Once you’ve got the linker & other compilation tools installed (as the above link says, that’ll take a while), you’ll need to let cargo know to use them when compiling for the Linux target. Create a subdirectory to the my_proj directory called .cargo; then in .cargo/config, write the following

linker = "x86_64-linux-musl-gcc"

You’ll also need to have rustup specify the target:

rustup target add x86_64-unknown-linux-musl

Compile & Deploy

To compile your executable for the server, run

cargo build --release --target=x86_64-unknown-linux-musl

Copy it to the server and you’re good to go:

scp target/x86_64-unknown-linux-musl/release/my_proj ⟨your_server_name⟩:

UPX (added 2016-10-17)

If you’re concerned about the binary size of your new executable, check out UPX. After installing it on my laptop via brew install upx, I ran upx -9 on an executable created with the above instructions. While the executable was an overly simplistic example, upx compressed it down to 34% of the original size. Even if you don’t care about the size of the binary once it’s on the server, it at least made the scp go faster.