Docker buildx "no builder ... found" / "no active builder" in CI

buildx was told to use a named builder that does not exist, or no builder is active at all. The command references a builder the runner never created (or already removed).

What this error means

A docker buildx build --builder <name> or a build expecting a prepared builder fails with no builder "<name>" found or no active builder instance. A build that creates the builder first works.

buildx output

ERROR: no builder "multi" found
# or: ERROR: no active builder instance, use "docker buildx create" to create one

Common causes

The named builder was never created

A step references --builder multi (or a builder selected in another step) but no docker buildx create --name multi ran on this runner, so there is nothing to use.

The builder was removed or lives in another step’s state

A builder created in a separate job/container is not present here, or a docker buildx rm removed it, leaving the reference dangling.

How to fix it

Create and select the builder first

Provision the builder in the same job before building.

Terminal

docker buildx create --name multi --driver docker-container --use
docker buildx build --builder multi .

Use setup-buildx-action in GitHub Actions

The action creates and selects a builder for the job.

.github/workflows/build.yml

- uses: docker/setup-buildx-action@v3
- uses: docker/build-push-action@v6
  with:
    context: .

How to prevent it

Create the builder in the same job that uses it.
Prefer setup-buildx-action so a builder is always present.
Avoid referencing a builder name across jobs that do not share buildx state.