Templates everything + Systemd improvements+fixes + Notifications for restart + Idempotent checks for multiple runs

templates/systemd/elasticsearch.j2

@@ -0,0 +1,50 @@
+[Unit]
+Description=Elasticsearch
+Documentation=http://www.elastic.co
+Wants=network-online.target
+After=network-online.target
+
+[Service]
+Environment=ES_HOME={{es_home}}
+Environment=CONF_DIR={{instance_config_directory}}
+Environment=CONF_FILE={{instance_config_directory}}/elasticsearch.yml
+Environment=DATA_DIR={{data_dir}}
+Environment=LOG_DIR={{log_dir}}
+Environment=PID_DIR={{pid_dir}}
+EnvironmentFile=-{{instance_default_file}}
+
+User={{es_user}}
+Group={{es_group}}
+
+ExecStart={{es_home}}/bin/elasticsearch \
+                                                -Des.pidfile=$PID_DIR/elasticsearch.pid \
+                                                -Des.default.path.home=$ES_HOME \
+                                                -Des.default.path.logs=$LOG_DIR \
+                                                -Des.default.path.data=$DATA_DIR \
+                                                -Des.default.config=$CONF_FILE \
+                                                -Des.default.path.conf=$CONF_DIR
+
+# Connects standard output to /dev/null
+StandardOutput=null
+
+# Connects standard error to journal
+StandardError=journal
+
+# When a JVM receives a SIGTERM signal it exits with code 143
+SuccessExitStatus=143
+
+# Specifies the maximum file descriptor number that can be opened by this process
+LimitNOFILE=65535
+
+# Specifies the maximum number of bytes of memory that may be locked into RAM
+# Set to "infinity" if you use the 'bootstrap.mlockall: true' option
+# in elasticsearch.yml and 'MAX_LOCKED_MEMORY=unlimited' in {{instance_default_file}}
+{% if m_lock_enabled %}
+LimitMEMLOCK=infinity
+{% endif %}
+
+# Shutdown delay in seconds, before process is tried to be killed with KILL (if configured)
+TimeoutStopSec=20
+
+[Install]
+WantedBy=multi-user.target