This step is necessary because files cannot be copied out of a Docker image. Note that build-package invokes docker build with a -target package argument, and build-variant invokes docker build with a -target variant argument.Īfter the docker build command, buildsys uses docker create to create a container from the built image. Both of these invoke a docker build command where the Dockerfile being built is at the root of the Bottlerocket repo (same Dockerfile for both subcommands). This program is also in the Bottlerocket tree and is responsible for calling docker build to use the SDK.īuildsys has two subcommands: build-package and build-variant. You may have noticed that the build.rs main function pasted above is shelling out to a program called buildsys. Thus, cargo make, cargo make world, and cargo make build all do the same thing: build a Bottlerocket variant! Docker and buildsys Our default target is build, which has an alias named world. All you need to know for now is that cargo make can be used like make. The syntax of the makefile is toml ( Makefile.toml). Go built from lookaside cache source, with and without pieĬargo Make serves the same purpose as Make, but is installed with, and driven by the cargo command, cargo make.Rust compiler built from source with a custom target, named bottlerocket, built for both glibc and musl.musl built from lookaside cache sources.GNU toolchain and glibc built from lookaside cache sources.Among the things included in the SDK are: These are all securely built from source using a lookaside cache to ensure stable, reproducible builds. The SDK is a container image including all the necessary tools and toolchains for a Bottlerocket build. We do not distribute RPM packages in the way that other Linux distributions do. We use RPM to package everything that will go into a Bottlerocket image, then “install” the RPMs when building the image. Specify which other RPM packages are dependencies when building or installing this package.īottlerocket does not have a package manager (such as yum or dnf).Specify which build artifacts will be installed, and where, when the RPM package is installed.Build the package with make or go or whatever.It essentially boils down to a shell with macros and some built-in functionality that is useful for Linux package distributors. spec file is like a script for creating one or more RPM packages. Ultimately, this process results in the kernel compiling in the normal manner (make, gcc, among others).
This function is running buildsys, which runs rpmbuild on kernel.spec inside of a docker build context, using the Bottlerocket SDK. Let ret = Command::new("buildsys").arg("build-package").status()? But, each of these directories also includes a build.rs file, which uses the Bottlerocket SDK to compile the actual package when build.rs is invoked.įor a more concrete example, when we compile the kernel package, the main function in build.rs is invoked: When we compile one of these packages, we produce an empty lib.
Each subdirectory of packages is a Rust crate that has an empty pkg.rs file.
For example, the packages in the packages directory are not typical Cargo packages. See the build scripts section of the Cargo Book for more details.īottlerocket takes advantage of this functionality to run docker build commands to invoke other build systems.
#Bottle rocket plano code#
Common use cases include compiling C code that is linked by the rust project, generating Rust code files, etc.
This feature can be used for whatever you want. The program defined by build.rs will be compiled and executed prior to building the Cargo package on which cargo build was invoked. Another feature, build.rs, allows us to extend Cargo to manage Bottlerocket’s entire build process.Īny Cargo project can include a file in the same directory as its Cargo.toml named build.rs. Cargo offers many great features, including dependency graph resolution and a flexible manifest format. Because Bottlerocket’s first-party code is written in Rust, the choice to drive all build processes from Cargo gives developers a single, familiar interface. The Bottlerocket build is unique in that it uses Cargo, the Rust package manager and build orchestrator, to drive all build processes, even those that are unrelated to Cargo packages. This article is the result of my exploration and will help you understand how the Bottlerocket build system uses Cargo, RPM, and Docker to create a Bottlerocket image. Bottlerocket is an open source, special-purpose operating system designed for hosting Linux containers, which was launched in 2020.Īs I delved into the Bottlerocket build system for a deeper understanding, I found it helpful to describe the system in detail (a form of rubber-duck debugging).
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