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Customizing your Buildkit installation


This documentation is for an older version of Dagger, which is no longer actively maintained.

We encourage you to upgrade and refer to the documentation for the most current version.

If you cannot upgrade to the latest version, please contact us in the help forum on Discord. When contacting us, please let us know why you cannot move to the latest version. From there, our team will work with you on your use case.

Using a custom buildkit daemon

Dagger can be configured to use an existing buildkit daemon, running either locally or remotely. This can be done using the environment variable BUILDKIT_HOST.

To use a buildkit daemon listening on an unix domain socket (usually in /var/run or /run):

export BUILDKIT_HOST=unix:///var/run/buildkit/buildkitd.sock

Make sure the user running dagger has appropriate permissions (rw) on the socket file.

To use a buildkit daemon listening on TCP port 1234 on localhost:

export BUILDKIT_HOST=tcp://localhost:1234

To use a buildkit daemon running in a container named "super-buildkit" on the local docker host:

export BUILDKIT_HOST=docker-container://super-buildkit

Using a custom remote buildkit running in Docker

Dagger can also be configured to use a remote buildkit daemon running in a Docker container. This an be done using the environment variable DOCKER_HOST.

export DOCKER_HOST=ssh://user@IP

You will also need to set the BUILDKIT_HOST environment variable explained above.

Running a custom buildkit container in Docker

To run a customized Buildkit version with Docker, this can be done using the below command:

docker run -d --name dagger-buildkitd --privileged --network=host

OpenTelemetry Support

Both Dagger and buildkit support opentelemetry. To capture traces to Jaeger, set the OTEL_EXPORTER_JAEGER_ENDPOINT environment variable to the collection address.

A docker-compose file is available to help bootstrap the tracing environment:

docker-compose -f ./dagger-main/tracing.compose.yaml up -d
export BUILDKIT_HOST=docker-container://dagger-buildkitd-jaeger
export OTEL_EXPORTER_JAEGER_ENDPOINT=http://localhost:14268/api/traces
export JAEGER_TRACE=localhost:6831

dagger up

You can then go to http://localhost:16686/ in your browser to see the traces.