[dev] always use the first node to generate descriptions

Some clusters are heterogeneous. We sort nodes before picking the first
node to avoid cases where we would use different nodes to generate
descriptions. Apparently different ruby versions sort hashes
differently.

lib/refrepo/gen/reference-api.rb

@@ -210,7 +210,8 @@ def generate_reference_api
 
       # Add nodes details to cluster description
       cluster['nodes_count'] = cluster['nodes'].length
-      cluster['nodes_description'] = gen_node_description(cluster['nodes'].values.first)
+      first_node = cluster['nodes'].values.select { |x| not x['status'] == 'retired' }.sort_by { |x| split_cluster_node(x['uid']) }.first # use first non-retired node
+      cluster['nodes_description'] = gen_node_description(first_node)
 
       # Write cluster info w/o nodes entries
       write_json(cluster_path.join("#{cluster_uid}.json"),

lib/refrepo/utils.rb

@@ -52,3 +52,7 @@ class Hash
     h2
   end
 end
+
+def split_cluster_node(k)
+  [k[/(\D+)/, 1], k[/(\d+)/, 1].to_i, k[/-(\d+)/, 1].to_i]
+end