Clarify, document KUBE_OUTPUT_* variables

hack/lib/init.sh

@@ -41,9 +41,21 @@ fi
 # The root of the build/dist directory
 KUBE_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd -P)"
 
-KUBE_OUTPUT_SUBPATH="${KUBE_OUTPUT_SUBPATH:-_output/local}"
-KUBE_OUTPUT="${KUBE_ROOT}/${KUBE_OUTPUT_SUBPATH}"
-KUBE_OUTPUT_BIN="${KUBE_OUTPUT}/bin"
+# Where output goes.  We should avoid redefining these anywhere else.
+#
+# KUBE_OUTPUT: the root directory (absolute) where this build should drop any
+#     files (subdirs are encouraged).
+# KUBE_OUTPUT_BIN: the directory in which compiled binaries will be placed,
+#     under OS/ARCH specific subdirs
+# THIS_PLATFORM_BIN: a symlink to the output directory for binaries built for
+#     the current host platform (e.g. build/test tools).
+#
+# Compat: The KUBE_OUTPUT_SUBPATH variable is sometimes passed in by callers.
+# If it is specified, we'll use it in KUBE_OUTPUT.
+_KUBE_OUTPUT_SUBPATH="${KUBE_OUTPUT_SUBPATH:-_output/local}"
+export KUBE_OUTPUT="${KUBE_ROOT}/${_KUBE_OUTPUT_SUBPATH}"
+export KUBE_OUTPUT_BIN="${KUBE_OUTPUT}/bin"
+export THIS_PLATFORM_BIN="${KUBE_ROOT}/_output/bin"
 
 # This controls rsync compression. Set to a value > 0 to enable rsync
 # compression for build container
@@ -53,9 +65,6 @@ KUBE_RSYNC_COMPRESS="${KUBE_RSYNC_COMPRESS:-0}"
 # the connections to localhost in scripts will time out
 export no_proxy="127.0.0.1,localhost${no_proxy:+,${no_proxy}}"
 
-# This is a symlink to binaries for "this platform", e.g. build tools.
-export THIS_PLATFORM_BIN="${KUBE_ROOT}/_output/bin"
-
 source "${KUBE_ROOT}/hack/lib/util.sh"
 source "${KUBE_ROOT}/hack/lib/logging.sh"
 
@@ -66,9 +75,6 @@ source "${KUBE_ROOT}/hack/lib/version.sh"
 source "${KUBE_ROOT}/hack/lib/golang.sh"
 source "${KUBE_ROOT}/hack/lib/etcd.sh"
 
-KUBE_OUTPUT_HOSTBIN="${KUBE_OUTPUT_BIN}/$(kube::util::host_platform)"
-export KUBE_OUTPUT_HOSTBIN
-
 # list of all available group versions.  This should be used when generated code
 # or when starting an API server that you want to have everything.
 # most preferred version for a group should appear first

hack/make-rules/test-cmd.sh

@@ -64,7 +64,7 @@ function run_kube_apiserver() {
   # Enable features
   ENABLE_FEATURE_GATES=""
 
-  "${KUBE_OUTPUT_HOSTBIN}/kube-apiserver" \
+  "${THIS_PLATFORM_BIN}/kube-apiserver" \
     --bind-address="127.0.0.1" \
     --authorization-mode="${AUTHORIZATION_MODE}" \
     --secure-port="${SECURE_API_PORT}" \
@@ -119,7 +119,7 @@ current-context: local-context
 EOF
 
   kube::log::status "Starting controller-manager"
-  "${KUBE_OUTPUT_HOSTBIN}/kube-controller-manager" \
+  "${THIS_PLATFORM_BIN}/kube-controller-manager" \
     --kube-api-content-type="${KUBE_TEST_API_TYPE-}" \
     --cluster-signing-cert-file=hack/testdata/ca/ca.crt \
     --cluster-signing-key-file=hack/testdata/ca/ca.key \

hack/update-openapi-spec.sh

@@ -70,7 +70,7 @@ fi
 # Start kube-apiserver
 # omit enums from static openapi snapshots used to generate clients until #109177 is resolved
 kube::log::status "Starting kube-apiserver"
-"${KUBE_OUTPUT_HOSTBIN}/kube-apiserver" \
+"${THIS_PLATFORM_BIN}/kube-apiserver" \
   --bind-address="${API_HOST}" \
   --secure-port="${API_PORT}" \
   --etcd-servers="http://${ETCD_HOST}:${ETCD_PORT}" \