contrib: example script for checking static consistency

contrib/example-scripts/check-mars-consistent.sh

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+#!/bin/bash
+#
+# This file is part of MARS project: http://schoebel.github.io/mars/
+#
+# Copyright (C) 2015 Thomas Schoebel-Theuer
+# Copyright (C) 2015 1&1 Internet AG
+#
+# 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 2 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, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+############################################################
+
+# TST summer 2015 lab prototype
+#
+# check_mars_consistent.sh
+#
+# This script is NOT for deciding whether a switchover is
+# possible.
+#
+# It tests a much simpler condition: whether a _potential_ target
+# of a switchover is principally / _statically usable_ for switchover
+# at all. 
+#
+# This is a true subset of the conditions checked by check_mars_switchable.sh.
+#
+# NOTICE: this does to take split brain into account. It cannot tell you
+# which side is the "correct" one.
+#
+# Please use check_mars_switchable.sh for deciding whether an actual
+# switchover should be started.
+
+# Allow overrides of default values by external config file
+for path in {.,$HOME,/etc/defaults}/check-mars-consistent.conf; do
+    [[ -r $path ]] && . $path
+done
+
+# This script works on a single resource, or on "all".
+# When no argument is given, treat as "all".
+
+if [[ "$1" = "all" ]] || [[ "$1" = "" ]] ; then
+    rc=0
+    for resource in $(marsadm view-my-resources 2> /dev/null); do
+	$0 $resource || (( rc++ ))
+    done
+    exit $rc
+fi
+
+resource="$1"
+
+
+# Check whether the resource is already Primary.
+# It does not make any sense to switchover to itself.
+# But anyway, we simply say "OK", because the primary side
+# is always consistent by _definition_.
+
+if (( $(marsadm view-is-primary $resource 2> /dev/null) > 0 )); then
+    echo "OK: resource '$resource' is consistent at generic mars level."
+    exit 0
+fi
+
+# Check whether sync has finished
+
+if (( $(marsadm view-sync-rest $resource 2> /dev/null) > 0 )); then
+    echo "ERROR: resource '$resource' is inconsistent because it has not (yet) reached sync"
+    exit 1
+fi
+
+
+# Check whether consistency has been violated
+
+if (( $(marsadm view-is-consistent $resource 2> /dev/null) < 1 )); then
+    echo "ERROR: resource '$resource' is not (yet) consistent"
+    exit 1
+fi
+
+# Finally: no errors found
+
+echo "OK: resource '$resource' is consistent at generic mars level."
+exit 0