$ echo 'FROM alpine' > Dockerfile
$ docker buildx build . -t gcr.io/.../cache-test:latest --push
[+] Building 5.4s (5/5) FINISHED
=> [internal] load .dockerignore 0.0s
=> => transferring context: 2B 0.0s
=> [internal] load build definition from Dockerfile 0.0s
=> => transferring dockerfile: 49B 0.0s
=> [internal] load metadata for docker.io/library/alpine:latest 1.3s
=> CACHED [1/1] FROM docker.io/library/alpine@sha256:c0e9560cda118f9ec63ddefb4a173a2b2a0347082d7dff7dc14272e7841a5b5a 0.0s
=> => resolve docker.io/library/alpine@sha256:c0e9560cda118f9ec63ddefb4a173a2b2a0347082d7dff7dc14272e7841a5b5a 0.0s
=> exporting to image 4.1s
=> => exporting layers 0.0s
=> => exporting manifest sha256:4567b80f4b7d8f139e9574aaa0850c8c4d89cc36b40f973902eab249492a78c6 0.0s
=> => exporting config sha256:8d19be48f0403c567476dc8607fc05eeb8a33846798029f7b4bd2e94f3ee331f 0.0s
=> => pushing layers 2.9s
=> => pushing manifest for gcr.io/<project>/cache-test:latest 1.1s
$ docker buildx build . -t gcr.io/<project>/cache-test:v1 --push
[+] Building 2.3s (5/5) FINISHED
=> [internal] load .dockerignore 0.0s
=> => transferring context: 2B 0.0s
=> [internal] load build definition from Dockerfile 0.0s
=> => transferring dockerfile: 31B 0.0s
=> [internal] load metadata for docker.io/library/alpine:latest 1.3s
=> CACHED [1/1] FROM docker.io/library/alpine@sha256:c0e9560cda118f9ec63ddefb4a173a2b2a0347082d7dff7dc14272e7841a5b5a 0.0s
=> => resolve docker.io/library/alpine@sha256:c0e9560cda118f9ec63ddefb4a173a2b2a0347082d7dff7dc14272e7841a5b5a 0.0s
=> ERROR exporting to image 1.0s
=> => exporting layers 0.0s
=> => exporting manifest sha256:4567b80f4b7d8f139e9574aaa0850c8c4d89cc36b40f973902eab249492a78c6 0.0s
=> => exporting config sha256:8d19be48f0403c567476dc8607fc05eeb8a33846798029f7b4bd2e94f3ee331f 0.0s
=> => pushing layers 0.2s
=> => pushing manifest for gcr.io/<project>/cache-test:v1 0.7s
------
> exporting to image:
------
failed to solve: rpc error: code = Unknown desc = failed commit on ref "manifest-sha256:4567b80f4b7d8f139e9574aaa0850c8c4d89cc36b40f973902eab249492a78c6": unexpected status: 401 Unauthorized
The same commands when used in a non-buildx context work fine
$ docker version
Client: Docker Engine - Community
Version: 20.10.0-rc1
API version: 1.41
Go version: go1.13.15
Git commit: 5cc2396
Built: Tue Nov 17 22:48:41 2020
OS/Arch: linux/amd64
Context: default
Experimental: true
Server: Docker Engine - Community
Engine:
Version: 20.10.0-rc1
API version: 1.41 (minimum version 1.12)
Go version: go1.13.15
Git commit: 131bf7e
Built: Tue Nov 17 22:52:57 2020
OS/Arch: linux/amd64
Experimental: false
containerd:
Version: v1.4.1
GitCommit: c623d1b36f09f8ef6536a057bd658b3aa8632828
runc:
Version: 1.0.0-rc92
GitCommit: ff819c7e9184c13b7c2607fe6c30ae19403a7aff
docker-init:
Version: 0.19.0
GitCommit: de40ad0
$ uname -a
Linux howardjohn-glaptop2 5.7.17-1rodete4-amd64 #1 SMP Debian 5.7.17-1rodete4 (2020-10-01) x86_64 GNU/Linux
The same commands when used in a non-buildx context work fine