rework etcd3 install to be like other devstack services

This separates out the install phase early from the start phase to
make this mirror other services in devstack.

Depends-On: I4124dc7e3fd3b4d973979da85209ec991c0f8c4b

Change-Id: I76f8740448b25a48869ee80006e826baa6cafc2b

lib/etcd3

@@ -41,13 +41,6 @@ fi
 
 # start_etcd3() - Starts to run the etcd process
 function start_etcd3 {
-    # Don't install in sub nodes (multinode scenario)
-    if [ "$SERVICE_HOST" != "$HOST_IP" ]; then
-        return
-    fi
-
-    _install_etcd
-
     local cmd="$ETCD_BIN_DIR/etcd"
     cmd+=" --name $HOSTNAME --data-dir $ETCD_DATA_DIR"
     cmd+=" --initial-cluster-state new --initial-cluster-token etcd-cluster-01"
@@ -96,7 +89,7 @@ function cleanup_etcd3 {
     sudo rm -rf $ETCD_DATA_DIR
 }
 
-function _install_etcd {
+function install_etcd3 {
     echo "Installing etcd"
 
     # Make sure etcd3 downloads the correct architecture
@@ -115,10 +108,6 @@ function _install_etcd {
 
     ETCD_NAME=etcd-$ETCD_VERSION-linux-$ETCD_ARCH
 
-    # Install the libraries needed. Note: tooz for example does not have a hard dependency on these libraries
-    pip_install etcd3
-    pip_install etcd3gw
-
     # Create the necessary directories
     sudo mkdir -p $ETCD_BIN_DIR
     sudo mkdir -p $ETCD_DATA_DIR

lib/oslo

@@ -109,7 +109,14 @@ function install_oslo {
     _do_install_oslo_lib "stevedore"
     _do_install_oslo_lib "taskflow"
     _do_install_oslo_lib "tooz"
+    # installation of additional libraries
+    #
+    # os-traits for nova
     _do_install_oslo_lib "os-traits"
+
+    # etcd (because tooz does not have a hard dependency on these)
+    pip_install etcd3
+    pip_install etcd3gw
 }
 
 # Restore xtrace

stack.sh

@@ -813,6 +813,10 @@ if is_service_enabled neutron; then
     install_neutron_agent_packages
 fi
 
+if is_service_enabled etcd3; then
+    install_etcd3
+fi
+
 # Check Out and Install Source
 # ----------------------------