add check available compute ram
diff --git a/sensu/files/checks/check_nova_compute_available_ram.sh b/sensu/files/checks/check_nova_compute_available_ram.sh
new file mode 100644
index 0000000..3477d74
--- /dev/null
+++ b/sensu/files/checks/check_nova_compute_available_ram.sh
@@ -0,0 +1,71 @@
+#!/bin/bash
+#checks nova hypervisor available RAM.
+
+usage() {
+    echo "checks nova hypervisor-stats for available RAM space on hypervisors."
+    echo "usage: ./check_nova_compute_ram_space.sh -u <openstack.user> -p <openstack.password> -t <openstack.tenant> -h 'http://<openstack.host>:<openstack.port>/v2.0' -r <region.name> -w <warning.threshold> [default 100] -c <critical.threshold> [default 30]"
+    exit 1
+}
+
+if [[ ! $@ =~ ^\-.+ ]]
+then
+        usage
+fi
+
+while getopts ":u:p:t:h:r:w:c:" opt; do
+    case $opt in
+        u)
+            USER=${OPTARG};;
+        p)
+            PASSWD=${OPTARG};;
+        t)
+            TENANT=${OPTARG};;
+        h)
+            HOST=${OPTARG};;
+        r)
+            REGION=${OPTARG};;
+        w)
+            WARN=${OPTARG};;
+        c)
+            CRIT=${OPTARG};;
+       \?)
+            echo "Invalid option"
+            usage;;
+        : ) echo "Option -"$OPTARG" requires an argument." >&2
+            usage;;
+    esac
+done
+
+WARN=${WARN:-100}
+CRIT=${CRIT:-30}
+
+exit_ok() {
+    echo "OK: $*"
+    exit 0
+}
+exit_warning() {
+    echo "WARNING: $*"
+    exit 1
+}
+exit_critical() {
+    echo "CRITICAL: $*"
+    exit 2
+}
+
+FREE_RAM=$(nova --os-username $USER --os-password $PASSWD --os-tenant-name $TENANT --os-auth-url $HOST --os-region-name $REGION hypervisor-stats | grep free_ram_mb | awk '{print $4}')
+
+if [[ -z $FREE_RAM ]]; then
+        exit_critical "Unknown error"
+fi
+
+if [[ -n $FREE_RAM ]]; then
+        if [[ $FREE_RAM -le $WARN ]]; then
+                exit_warning Available RAM $FREE_RAM GB
+	elif [[ $FREE_RAM -le $CRIT ]]; then
+                exit_critical Available RAM $FREE_RAM GB
+	else
+		exit_ok Available RAM $FREE_RAM GB
+        fi
+else
+        exit_critical "Unknown error"
+fi
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