Curl-install support for CoreOS

This patch adds curl-install support for CoreOS. REX-Ray is installed to
`/opt/bin/rexay` and is configured as a SystemV service. All the other
standard paths remain the same as they exist under the `/var` directory,
and it is mounted at `/` which is `RW` unlike some of its children.

install.sh

@@ -2,45 +2,62 @@
 
 REPO="${1:-stable}"
 URL=https://dl.bintray.com/emccode/rexray/$REPO/latest
+OS=$(uname -s)
 ARCH=$(uname -m)
 SUDO=$(which sudo)
+BIN_DIR=/usr/bin
+BIN_FILE=$BIN_DIR/rexray
 
 function sudo() {
     if [[ $(id -u) -eq 0 ]]; then $@; else $SUDO $@; fi
 }
 
+function is_coreos() {
+    grep -q DISTRIB_ID=CoreOS /etc/lsb-release &> /dev/null
+    if [[ $? -eq 0 ]]; then echo 0; else echo 1; fi
+}
+
+IS_COREOS=$(is_coreos)
+
 # how to detect the linux distro was taken from http://bit.ly/1JkNwWx
-if [ -e "/etc/redhat-release" -o \
-     -e "/etc/redhat-version" ]; then
+if [[ -e /etc/redhat-release || \
+      -e /etc/redhat-version ]]; then
 
     #echo "installing rpm"
     sudo rpm -ih --quiet $URL/rexray-latest-$ARCH.rpm > /dev/null
 
-elif [ "$ARCH" = "x86_64" -a \
-       -e "/etc/debian-release" -o \
-       -e "/etc/debian-version" -o \
-       -e "/etc/lsb-release" ]; then
+elif [[ $ARCH = x86_64 && \
+       (-e /etc/debian-release || \
+        -e /etc/debian-version || \
+        -e /etc/lsb-release) &&
+        $IS_COREOS -eq 1 ]]; then
 
     #echo "installing deb"
     curl -sSLO $URL/rexray-latest-$ARCH.deb && \
         sudo dpkg -i rexray-latest-$ARCH.deb && \
         rm -f rexray-latest-$ARCH.deb
 
-else
-
-    #echo "installing binary"
-    curl -sSLO $URL/rexray-$(uname -s)-$ARCH.tar.gz && \
-        sudo tar xzf rexray-$(uname -s)-$ARCH.tar.gz -C /usr/bin && \
-        rm -f rexray-$(uname -s)-$ARCH.tar.gz && \
-        sudo chmod 0755 /usr/bin/rexray && \
-        sudo chown 0 /usr/bin/rexray && \
-        sudo chgrp 0 /usr/bin/rexray && \
-        sudo /usr/bin/rexray install
-
+else 
+    if [[ $IS_COREOS -eq 0 ]]; then
+        BIN_DIR=/opt/bin
+        BIN_FILE=$BIN_DIR/rexray
+    elif [[ $OS = Darwin ]]; then
+        BIN_DIR=/usr/local/bin
+        BIN_FILE=$BIN_DIR/rexray
+    fi
+
+    sudo mkdir -p $BIN_DIR && \
+      curl -sSLO $URL/rexray-$OS-$ARCH.tar.gz && \
+      sudo tar xzf rexray-$OS-$ARCH.tar.gz -C $BIN_DIR && \
+      rm -f rexray-$OS-$ARCH.tar.gz && \
+      sudo chmod 0755 $BIN_FILE && \
+      sudo chown 0 $BIN_FILE && \
+      sudo chgrp 0 $BIN_FILE && \
+      sudo $BIN_FILE install
 fi
 
 echo
-echo "REX-Ray has been installed to /usr/bin/rexray"
+echo "REX-Ray has been installed to $BIN_FILE"
 echo
-/usr/bin/rexray version
+$BIN_FILE version
 echo