Building flannel

March 8, 2024 ยท View on GitHub

The most reliable way to build flannel is by using Docker.

Building in a Docker container

To build flannel in a container run make dist/flanneld-amd64. You will now have a flanneld-amd64 binary in the dist directory.

Building for other platforms

If you're not running amd64 then you need to manually set ARCH before running make. For example, to produce a flanneld-s390x binary and image, run

  • ARCH=s390x make image

If you want to cross-compile for a different platform (e.g. you're running amd64 but you want to produce arm binaries) then you need the qemu-static binaries to be present in /usr/bin. They can be installed on Ubuntu with

  • sudo apt-get install qemu-user-static

Then you should be able to set the ARCH as above

  • ARCH=arm make image

Building a multi-arch image

To build the multi-arch image of flannel locally, you need to install Docker buildx. Then you can use the following target:

make build-multi-arch

If you don't already have a builder running locally, you can this target to start it:

make buildx-create-builder

See the buildx documentation for more details.

Running the tests locally

To run the end-to-end tests locally, you need to installl Docker compose.

Building manually

  1. Make sure you have required dependencies installed on your machine.
    • On Ubuntu, run sudo apt-get install linux-libc-dev golang gcc. If the golang version installed is not 1.7 or higher. Download the newest golang and install manually. To build the flannel.exe on windows, mingw-w64 is also needed. Run command sudo apt-get install mingw-w64
    • On Fedora/Redhat, run sudo yum install kernel-headers golang gcc glibc-static.
  2. Git clone the flannel repo. It MUST be placed in your GOPATH under github.com/flannel-io/flannel: cd $GOPATH/src; git clone https://github.com/flannel-io/flannel.git
  3. Run the build script, ensuring that CGO_ENABLED=1: cd flannel; CGO_ENABLED=1 make dist/flanneld for linux usage. Run the build script, ensuring that CGO_ENABLED=1: cd flannel; CGO_ENABLED=1 make dist/flanneld.exe for windows usage.