Addresses https://github.com/docker/setup-buildx-action/issues/45
Simple repro:
```
$ buildx create --platform linux/amd64 --use
$ buildx build - <<EOF
from scratch
EOF
```
Since https://github.com/docker/buildx/pull/370 a `platform` driver-opt was automatically inserted with the value specified by `--platform` flag on regardless of the type of driver, even though it was only used in the kubernetes driver. However, because the docker-container driver is pedantic about the options being passed, it errored out.
Another side-effect I suspect is that with the kubernetes driver it was now possible to specify the platforms in two different ways: `--driver-opt platform=...` and `--platform`.
This patch reverts completely the `platform` driver-opt and instead ensures the platforms information is passed onto the kubernetes driver via variables.
Signed-off-by: Tibor Vass <tibor@docker.com>
Tested with `kind` and GKE.
Note: "nodes" shown in `docker buildx ls` are unrelated to Kubernetes "nodes".
Probably buildx should come up with an alternative term.
Usage:
$ kind create cluster
$ export KUBECONFIG="$(kind get kubeconfig-path --name="kind")"
$ docker buildx create --driver kubernetes --driver-opt replicas=3 --use
$ docker buildx build -t foo --load .
`--load` loads the image into the local Docker.
Driver opts:
- `image=IMAGE` - Sets the container image to be used for running buildkit.
- `namespace=NS` - Sets the Kubernetes namespace. Defaults to the current namespace.
- `replicas=N` - Sets the number of `Pod` replicas. Defaults to 1.
- `rootless=(true|false)` - Run the container as a non-root user without `securityContext.privileged`. Defaults to false.
- `loadbalance=(sticky|random)` - Load-balancing strategy. If set to "sticky", the pod is chosen using the hash of the context path. Defaults to "sticky"
Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
