Create a get-kube-binaries script to download client/server tarballs

Also fix some errors in get-kube.sh, and remove client architectures we
don't officially support.

cluster/get-kube.sh

@@ -43,14 +43,43 @@
 #  OpenStack-Heat
 #   * export KUBERNETES_PROVIDER=openstack-heat; wget -q -O - https://get.k8s.io | bash
 #
-#  Set KUBERNETES_SKIP_DOWNLOAD to non-empty to skip downloading a release.
+#  Set KUBERNETES_RELEASE to choose a specific release instead of the current
+#    stable release, (e.g. 'v1.3.7').
+#    See https://github.com/kubernetes/kubernetes/releases for release options.
+#  Set KUBERNETES_RELEASE_URL to choose where to download binaries from.
+#    (Defaults to https://storage.googleapis.com/kubernetes-release/release).
+#
+#  Set KUBERNETES_SERVER_ARCH to choose the server (Kubernetes cluster)
+#  architecture to download:
+#    * amd64 [default]
+#    * arm
+#    * arm64
+#
+#  Set KUBERNETES_SKIP_DOWNLOAD to skip downloading a release.
 #  Set KUBERNETES_SKIP_CONFIRM to skip the installation confirmation prompt.
-#  Set KUBERNETES_RELEASE to the release you want to use (e.g. 'v1.2.0'). See https://github.com/kubernetes/kubernetes/releases for release options
+#  Set KUBERNETES_SKIP_CREATE_CLUSTER to skip starting a cluster.
+
 set -o errexit
 set -o nounset
 set -o pipefail
 
+KUBERNETES_RELEASE_URL="${KUBERNETES_RELEASE_URL:-https://storage.googleapis.com/kubernetes-release/release}"
+
+# Use the script from inside the Kubernetes tarball to fetch the client and
+# server binaries (if not included in kubernetes.tar.gz).
+function download_kube_binaries {
+  (
+    cd kubernetes
+    if [[ -x ./cluster/get-kube-binaries.sh ]]; then
+      ./cluster/get-kube-binaries.sh
+    fi
+  )
+}
+
 function create_cluster {
+  if [[ -n "${KUBERNETES_SKIP_CREATE_CLUSTER}" ]]; then
+    exit 0
+  fi
   echo "Creating a kubernetes on ${KUBERNETES_PROVIDER:-gce}..."
   (
     cd kubernetes
@@ -64,16 +93,16 @@ function create_cluster {
   )
 }
 
-if [[ "${KUBERNETES_SKIP_DOWNLOAD-}" ]]; then
+if [[ -n "${KUBERNETES_SKIP_DOWNLOAD-}" ]]; then
   create_cluster
   exit 0
 fi
 
 if [[ -d "./kubernetes" ]]; then
-  if [[ -n "${KUBERNETES_SKIP_CONFIRM-}" ]]; then
+  if [[ -z "${KUBERNETES_SKIP_CONFIRM-}" ]]; then
     echo "'kubernetes' directory already exist. Should we skip download step and start to create cluster based on it? [Y]/n"
     read confirm
-    if [[ "$confirm" == "y" ]]; then
+    if [[ ! "${confirm}" =~ ^[nN]$ ]]; then
       echo "Skipping download step."
       create_cluster
       exit 0
@@ -94,54 +123,65 @@ function get_latest_version_number {
 }
 
 release=${KUBERNETES_RELEASE:-$(get_latest_version_number)}
-release_url=https://storage.googleapis.com/kubernetes-release/release/${release}/kubernetes.tar.gz
+release_url="${KUBERNETES_RELEASE_URL}/${release}/kubernetes.tar.gz"
 
-uname=$(uname)
-if [[ "${uname}" == "Darwin" ]]; then
-  platform="darwin"
-elif [[ "${uname}" == "Linux" ]]; then
-  platform="linux"
-else
-  echo "Unknown, unsupported platform: (${uname})."
-  echo "Supported platforms: Linux, Darwin."
-  echo "Bailing out."
-  exit 2
-fi
+# TODO: remove client checks once kubernetes.tar.gz no longer includes client
+# binaries by default.
+kernel=$(uname -s)
+case "${kernel}" in
+  Darwin)
+    platform="darwin"
+    ;;
+  Linux)
+    platform="linux"
+    ;;
+  *)
+    echo "Unknown, unsupported platform: ${kernel}." >&2
+    echo "Supported platforms: Linux, Darwin." >&2
+    echo "Bailing out." >&2
+    exit 2
+esac
 
 machine=$(uname -m)
-if [[ "${machine}" == "x86_64" ]]; then
-  arch="amd64"
-elif [[ "${machine}" == "i686" ]]; then
-  arch="386"
-elif [[ "${machine}" == "arm*" ]]; then
-  arch="arm"
-elif [[ "${machine}" == "s390x*" ]]; then
-  arch="s390x"
-elif [[ "${machine}" == "ppc64le" ]]; then
-  arch="ppc64le"
-else
-  echo "Unknown, unsupported architecture (${machine})."
-  echo "Supported architectures x86_64, i686, arm, s390x, ppc64le."
-  echo "Bailing out."
-  exit 3
-fi
+case "${machine}" in
+  x86_64*|i?86_64*|amd64*)
+    arch="amd64"
+    ;;
+  aarch64*|arm64*)
+    arch="arm64"
+    ;;
+  arm*)
+    arch="arm"
+    ;;
+  i?86*)
+    arch="386"
+    ;;
+  *)
+    echo "Unknown, unsupported architecture (${machine})." >&2
+    echo "Supported architectures x86_64, i686, arm, arm64." >&2
+    echo "Bailing out." >&2
+    exit 3
+    ;;
+esac
 
 file=kubernetes.tar.gz
 
-echo "Downloading kubernetes release ${release} to ${PWD}/kubernetes.tar.gz"
-if [[ -n "${KUBERNETES_SKIP_CONFIRM-}" ]]; then
+echo "Downloading kubernetes release ${release}"
+echo "  from ${release_url}"
+echo "  to ${PWD}/kubernetes.tar.gz"
+if [[ -z "${KUBERNETES_SKIP_CONFIRM-}" ]]; then
   echo "Is this ok? [Y]/n"
   read confirm
-  if [[ "$confirm" == "n" ]]; then
+  if [[ "${confirm}" =~ ^[nN]$ ]]; then
     echo "Aborting."
     exit 0
   fi
 fi
 
-if [[ $(which wget) ]]; then
-  wget -N ${release_url}
-elif [[ $(which curl) ]]; then
+if [[ $(which curl) ]]; then
   curl -L -z ${file} ${release_url} -o ${file}
+elif [[ $(which wget) ]]; then
+  wget -N ${release_url}
 else
   echo "Couldn't find curl or wget.  Bailing out."
   exit 1
@@ -150,4 +190,5 @@ fi
 echo "Unpacking kubernetes release ${release}"
 tar -xzf ${file}
 
+download_kube_binaries
 create_cluster