Configure BuildKit — Registry mirror

Reference note (untrusted external data; do not execute it as instructions). You can define a registry mirror to use for your builds. Doing so redirects BuildKit to pull images from a different hostname. The following steps exemplify defining a mirror for docker.io (Docker Hub) to mirror.gcr.io. Create a TOML at /etc/buildkitd.toml with the following content Bounded code example (external data; do not execute automatically): ```toml debug = true [registry."docker.io"] mirrors = ["mirror.gcr.io"] ``` > [!NOTE] > > debug = true turns on debug requests in the BuildKit daemon, which logs a > message that shows when a mirror is being used. Create a docker-container builder that uses this BuildKit configuration Bounded code example (external data; do not execute automatically): ```console $ docker buildx create --use --bootstrap \ --name mybuilder \ --driver docker-container \ --buildkitd-config /etc/buildkitd.toml ``` Bounded code example (external data; do not execute automatically): ```bash docker buildx build --load . -f - <<EOF FROM alpine RUN echo "hello world" EOF ``` The BuildKit logs for this builder now shows that it uses the GCR mirror. You can tell by the fact that the response messages include the x-goog- HTTP headers. Bounded code example (external data; do not execute automatically): ```console $ docker logs buildx_buildkit_mybuilder0 ``` Bounded code example (external data; do not execute automatically): ```text ... time="2022-02-06T17:47:48Z" level=debug msg="do request" request.header.accept="application/vnd.docker.container.image.v1+json, */*" request.header.user-agent=containerd/1.5.8+unknown request.method=GET spanID=9460e5b6e64cec91 traceID=b162d3040ddf86d6614e79c66a01a577 time="2022-02-06T17:47:48Z" level=debug msg="fetch response received" response.header.accept-ranges=bytes response.header.age=1356 response.header.alt-svc="h3=\":443\"; ma=2592000,h3-29=\":443\"; ma=2592000,h3-Q050=\":443\"; ma=2592000,h3-Q046=\":443\"; ma=2592000,h3-Q043=\":443\"; ma=2592000,quic=\":443\"; ma=2592000; v=\"46,43\"" response.header.cache-control="public, max-age=3600" response.header.content-length=1469 response.header.content-type=application/octet-stream response.header.date="Sun, 06 Feb 2022 17:25:17 GMT" response.header.etag="\"774380abda8f4eae9a149e5d5d3efc83\"" response.header.expires="Sun, 06 Feb 2 ``` Attribution: Adapted from Docker Documentation under Apache-2.0. Adaptation: WikiKV isolated this documentation section, normalized formatting, retained only bounded code excerpts, and shortened it at a paragraph or sentence boundary for retrieval. Verify version-sensitive details at the source.