Generate Build Container

1. set env variable PATH_TO_KUBERNETES_REPO to the path to your local kubernetes/kubernetes copy:
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   export GHUSER="mtrachier"
   export PATH_TO_KUBERNETES_REPO="/Users/$GHUSER/go/src/github.com/kubernetes/kubernetes"
   

2. set env variable GOVERSION to the expected version of go for the kubernetes/kubernetes version checked out:
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   export GOVERSION=$(yq -e '.dependencies[] | select(.name == "golang: upstream version").version' $PATH_TO_KUBERNETES_REPO/build/dependencies.yaml)
   

3. set env variable GOIMAGE to the expected container image to base our custom build image on:
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   export GOIMAGE="golang:${GOVERSION}-alpine"
   

4. set env variable BUILD_CONTAINER to the contents of a dockerfile for the build container:
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   export BUILD_CONTAINER="FROM ${GOIMAGE}\nRUN apk add --no-cache bash gnupg git make tar gzip curl git coreutils rsync alpine-sdk"
   

5. use Docker to create the build container:
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   echo -e $BUILD_CONTAINER | docker build -t ${GOIMAGE}-dev -