deploy: Add constants module

Use constants to refer to roles defined in conf files.
Add constants related to snf-deploy state.
Signed-off-by: Dimitris Aragiorgis <dimara@grnet.gr>

snf-deploy/snfdeploy/constants.py

+# Copyright (C) 2010-2014 GRNET S.A.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+NS = "ns"
+DB = "db"
+MQ = "mq"
+ASTAKOS = "astakos"
+CYCLADES = "cyclades"
+PITHOS = "pithos"
+CLIENT = "client"
+ROUTER = "router"
+NFS = "nfs"
+CMS = "cms"
+STATS = "stats"
+CLUSTERS = "clusters"
+MASTER = "master"
+VMC = "vmc"
+DEV = "dev"
+BACKEND = "backend"
+
+VALUE_OK = "ok"
+STATUS_FILE = "snf_deploy_status"
+
+DEFAULT_NODE = "node1"
+DEFAULT_CLUSTER = "ganeti1"
+DEFAULT_SETUP = "synnefo"