Contribution Guide

• 1: Development setup
• 2: Making changes
• 3: Running tests
• 4: Submitting a pull request
• 5: Developer's certificate of origin

1 - Development setup

Building and Running Tetragon

For local development, you will likely want to build and run bare-metal Tetragon.

Requirements:

• go 1.18
• GNU make
• A running docker service
• libcap and libelf (in Debian systems, e.g., install libelf-dev and libcap-dev)

You can build Tetragon as follows:

make

If you want to use podman instead of docker, you can do the following (assuming you need to use sudo with podman):

CONTAINER_ENGINE='sudo podman' make

You can ignore /bin/sh: docker: command not found in the output.

To build using the local clang, you can use:

CONTAINER_ENGINE='sudo podman' LOCAL_CLANG=1 LOCAL_CLANG_FORMAT=1 make

See Dockerfile.clang for the minimal required version of clang.

You should now have a ./tetragon binary, which can be run as follows:

sudo ./tetragon --bpf-lib bpf/objs

Notes:

1. The --bpf-lib flag tells Tetragon where to look for its compiled BPF programs (which were built in the make step above).

2. If Tetragon fails with an error "BTF discovery: candidate btf file does not exist", then make sure that your kernel support BTF, otherwise place a BTF file where Tetragon can read it and specify its path with the --btf flag.

Running Code Generation

Tetragon uses code generation based on protoc to generate large amounts of boilerplate code based on our protobuf API. We similarly use automatic generation to maintain our k8s CRDs. Whenever you make changes to these files, you will be required to re-run code generation before your PR can be accepted.

To run codegen from protoc, run the following command from the root of the repository:

make codegen

And to run k8s CRD generation, run the following command from the root of the repository:

make generate

Finally, should you wish to modify any of the resulting codegen files (ending in .pb.go), do not modify them directly. Instead, you can edit the files in cmd/protoc-gen-go-tetragon and then re-run make codegen.

Building and running a Docker image

The base kernel should support BTF or a BTF file should be bind mounted on top of /var/lib/tetragon/btf inside container.

To build Tetragon image:

make image

To run the image:

docker run --name tetragon \
   --rm -it -d --pid=host \
   --cgroupns=host --privileged \
   -v /sys/kernel/btf/vmlinux:/var/lib/tetragon/btf \
   cilium/tetragon:latest \
   bash -c "/usr/bin/tetragon"

Run the tetra binary to get Tetragon events:

docker exec -it tetragon \
   bash -c "/usr/bin/tetra getevents -o compact"

Building and running as a systemd service

To build Tetragon tarball:

make tarball

Running Tetragon in kind

The scripts in contrib/localdev will help you run Tetragon locally in a kind cluster. First, ensure that docker, kind, kubectl, and helm are installed on your system. Then, run the following commands:

# Build Tetragon agent and operator images
make LOCAL_CLANG=0 image image-operator

# Bootstrap the cluster
contrib/localdev/bootstrap-kind-cluster.sh

# Install Tetragon
contrib/localdev/install-tetragon.sh --image cilium/tetragon:latest --operator cilium/tetragon-operator:latest

Verify that Tetragon is installed by running:

kubectl get pods -n kube-system

Local Development in Vagrant Box

If you are on a Mac, use Vagrant to create a dev VM:

vagrant up
vagrant ssh
make

If you are getting an error, you can try to run sudo launchctl load /Library/LaunchDaemons/org.virtualbox.startup.plist (from a Stackoverflow answer).

Local Development in Minikube

You can also run the tetragon agent directly (instead of in a pod). Here we describe how this can be done in minikube:

minikube start --driver=kvm2
minikube mount $HOME:$HOME # so that we can use .kube/config
./tetragon-operator --kube-config ~/.kube/config
make STATIC=1 tetragon
minikube ssh --  'sudo mkdir -p /var/run/cilium/tetragon'
minikube ssh sudo "sh -c 'NODE_NAME=minikube /home/kkourt/src/tetragon/tetragon --bpf-lib /home/kkourt/src/tetragon/bpf/objs --server-address unix:///var/run/cilium/tetragon/tetragon.sock --enable-k8s-api --k8s-kubeconfig-path /home/kkourt/.kube/config'"

What’s next

• See how to make your first changes.

2 - Making changes

1. Make sure the main branch of your fork is up-to-date:

   git fetch upstream
   git checkout main
   git merge upstream/main
   

   For further reference read github syncing a fork documentation.

2. Create a PR branch with a descriptive name, branching from main:

   git switch -c pr/${GITHUB_USERNAME_OR_ORG}/changes-to-something main
   

3. Make the changes you want.

4. Separate the changes into logical commits.

   • Describe the changes in the commit messages. Focus on answering the question why the change is required and document anything that might be unexpected.
   • If any description is required to understand your code changes, then those instructions should be code comments instead of statements in the commit description.
   • For submitting PRs, all commits need to be signed off (git commit -s). See the section Developer’s Certificate of Origin

5. Make sure your changes meet the following criteria:

   • New code is covered by Integration Testing.
   • End to end integration / runtime tests have been extended or added. If not required, mention in the commit message what existing test covers the new code.
   • Follow-up commits are squashed together nicely. Commits should separate logical chunks of code and not represent a chronological list of changes.

6. Run git diff --check to catch obvious white space violations

7. Build Tetragon with your changes included.

What’s next

• See how to run the tests of the project.
• See how to submit your first pull request.

3 - Running tests

See https://github.com/cilium/tetragon/tree/main/tests/vmtests.

What’s next

• See how to submit your first pull request.

4 - Submitting a pull request

Submitting a pull request

Contributions must be submitted in the form of pull requests against the upstream GitHub repository at https://github.com/cilium/tetragon.

1. Fork the Tetragon repository.

2. Push your changes to the topic branch in your fork of the repository.

3. Submit a pull request on https://github.com/cilium/tetragon.

Before hitting the submit button, please make sure that the following requirements have been met:

1. Each commit compiles and is functional on its own to allow for bisecting of commits.

2. All code is covered by unit and/or runtime tests where feasible.

3. All changes have been tested and checked for regressions by running the existing testsuite against your changes.

4. All commits contain a well written commit description including a title, description and a Fixes: #XXX line if the commit addresses a particular GitHub issue identified by its number. Note that the GitHub issue will be automatically closed when the commit is merged.

   doc: add contribution guideline and how to submit pull requests
   
   Tetragon Open Source project was just released and it does not include
   default contributing guidelines.
   
   This patch fixes this by adding:
   
   1. CONTRIBUTING.md file in the root directory as suggested by github documentation: https://docs.github.com/en/communities/setting-up-your-project-for-healthy-contributions/setting-guidelines-for-repository-contributors
   
   2. Development guide under docs directory with a section on how to submit pull requests.
   
   3. Moves the DEVELOP.md file from root directory to the `docs/contributing/development/` one.
   
   Fixes: #33
   
   Signed-off-by: Djalal Harouni <djalal@cilium.io>
   

   Note: Make sure to include a blank line in between commit title and commit description.

5. All commits are signed off. See the section Developer’s Certificate of Origin.

6. All important steps in Making changes have been followed.

5 - Developer's certificate of origin

To improve tracking of who did what, we’ve introduced a “sign-off” procedure, make sure to read and apply the Developer’s Certificate of Origin.