TT#30565 Check for already running instances and abort if so

In end of october we had many running instances because of aborted
ec2-ami-ce Jenkins jobs. To ensure this doesn't happen again
let's check for already running instances if we find any of them
abort within ec2-create-ce before creating any ones.

While this limits us to not have several of them running at the
same time (within the same region and using the same tag!), this
shouldn't be a problem for us for the time being.

Change-Id: I5707f611c6c8a08664a1dbbef08332c36dd2150f

ec2-create-ce

@@ -293,6 +293,19 @@ if [ -z "$NGCP_VERSION" ] ; then
   bailout 1
 fi
 
+# ensure we don't have any builds running already, see TT#30565
+NUM_RUNNING_INSTANCES=$(ec2-describe-instances --region "${AWS_REGION}" \
+                       --filter "instance-state-name=running" \
+		       --filter "tag:Purpose=${TAG_PURPOSE}" 2>/dev/null | \
+		       grep -c '^INSTANCE')
+if [ "$NUM_RUNNING_INSTANCES" -gt 0 ] ; then
+  echo "Error: there are running instances with tag $TAG_PURPOSE in region $AWS_REGION"  >&2
+  echo "Exiting to ensure we don't have instances running due to Jenkins job failures."  >&2
+  echo "Please ensure that those instances are stopped before trying to build new ones." >&2
+  echo "In case of questions contact someone with according AWS permissions."            >&2
+  bailout 1
+fi
+
 # if AMI_NAME is set to "none" then we get defaults from Jenkins, if
 # so then use the ngcp-ce-... naming schema
 if [ -n "$AMI_NAME" ] && [ "$AMI_NAME" != "none" ] ; then