fix: restore bin/docker-build functionality

bin/_docker.sh

@@ -31,7 +31,6 @@ export SUPPORTED_ARCHS=${SUPPORTED_ARCHS:-linux/amd64,linux/arm64}
 # Splitting of DOCKER_IMAGES variable is desired.
 # shellcheck disable=SC2206
 export DOCKER_IMAGES=(${DOCKER_IMAGES:-
-    cli-bin
     controller
     metrics-api
     debug

bin/build-cli-bin

@@ -2,9 +2,9 @@
 
 set -eu
 
-# Builds CLI binary for current platform only and outside docker to speed up things. Suitable for local development.
+# Builds CLI binary for current platform. Suitable for local development.
 # Note: This script is used by Brew when running `brew install linkerd`:
-# https://github.com/Homebrew/homebrew-core/pull/36957
+# https://github.com/Homebrew/homebrew-core/blob/main/Formula/l/linkerd.rb
 
 bindir=$( cd "${0%/*}" && pwd )
 rootdir=$( cd "$bindir"/.. && pwd )

bin/docker-build

@@ -13,10 +13,5 @@ bindir=$( cd "${0%/*}" && pwd )
 "$bindir"/docker-build-controller
 "$bindir"/docker-build-web
 "$bindir"/docker-build-debug
-if [ -z "${LINKERD_LOCAL_BUILD_CLI:-}" ]; then
-    "$bindir"/docker-build-cli-bin
-else
-    "$bindir"/build-cli-bin
-fi
 "$bindir"/docker-build-metrics-api
 "$bindir"/docker-build-tap

cli/Dockerfile

@@ -60,3 +60,10 @@ COPY --from=build-linux-arm64  /out/* /
 COPY --from=build-darwin       /out/* /
 COPY --from=build-darwin-arm64 /out/* /
 COPY --from=build-windows      /out/* /
+
+# NB: This image does not contain an `ENTRYPOINT` directive. The filesystem
+# of this image is used as a layer in other images in CI, and the CLI is
+# typically used by operators outside of a cluster.
+#
+# Running `docker build` for this image will likely fail with an error like:
+# "Error response from daemon: No command specified."