X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/ed1acd6fd780467ba69998e76e28fda61beedc0f..0eb72b526bf8bbb011551ecf019f604e17a534f1:/services/api/app/models/node.rb

diff --git a/services/api/app/models/node.rb b/services/api/app/models/node.rb
index affd8ee49a..bf1b636c52 100644
--- a/services/api/app/models/node.rb
+++ b/services/api/app/models/node.rb
@@ -1,3 +1,9 @@
+# Copyright (C) The Arvados Authors. All rights reserved.
+#
+# SPDX-License-Identifier: AGPL-3.0
+
+require 'tempfile'
+
 class Node < ArvadosModel
   include HasUuid
   include KindAndEtag
@@ -102,17 +108,19 @@ class Node < ArvadosModel
 
     # Assign slot_number
     if self.slot_number.nil?
-      try_slot = 0
-      begin
-        self.slot_number = try_slot
+      while true
+        n = self.class.available_slot_number
+        if n.nil?
+          raise "No available node slots"
+        end
+        self.slot_number = n
         begin
           self.save!
           break
         rescue ActiveRecord::RecordNotUnique
-          try_slot += 1
+          # try again
         end
-        raise "No available node slots" if try_slot == Rails.configuration.max_compute_nodes
-      end while true
+      end
     end
 
     # Assign hostname
@@ -134,6 +142,21 @@ class Node < ArvadosModel
 
   protected
 
+  def self.available_slot_number
+    # Join the sequence 1..max with the nodes table. Return the first
+    # (i.e., smallest) value that doesn't match the slot_number of any
+    # existing node.
+    connection.exec_query('SELECT n FROM generate_series(1, $1) AS slot(n)
+                          LEFT JOIN nodes ON n=slot_number
+                          WHERE slot_number IS NULL
+                          LIMIT 1',
+                          # query label:
+                          'Node.available_slot_number',
+                          # [col_id, val] for $1 vars:
+                          [[nil, Rails.configuration.max_compute_nodes]],
+                         ).rows.first.andand.first
+  end
+
   def ensure_ping_secret
     self.info['ping_secret'] ||= rand(2**256).to_s(36)
   end
@@ -171,22 +194,30 @@ class Node < ArvadosModel
     }
 
     if Rails.configuration.dns_server_conf_dir and Rails.configuration.dns_server_conf_template
+      tmpfile = nil
       begin
         begin
           template = IO.read(Rails.configuration.dns_server_conf_template)
-        rescue => e
+        rescue IOError, SystemCallError => e
           logger.error "Reading #{Rails.configuration.dns_server_conf_template}: #{e.message}"
           raise
         end
 
         hostfile = File.join Rails.configuration.dns_server_conf_dir, "#{hostname}.conf"
-        File.open hostfile+'.tmp', 'w' do |f|
+        Tempfile.open(["#{hostname}-", ".conf.tmp"],
+                                 Rails.configuration.dns_server_conf_dir) do |f|
+          tmpfile = f.path
           f.puts template % template_vars
         end
-        File.rename hostfile+'.tmp', hostfile
-      rescue => e
+        File.rename tmpfile, hostfile
+      rescue IOError, SystemCallError => e
         logger.error "Writing #{hostfile}: #{e.message}"
         ok = false
+      ensure
+        if tmpfile and File.file? tmpfile
+          # Cleanup remaining temporary file.
+          File.unlink tmpfile
+        end
       end
     end
 
@@ -205,7 +236,7 @@ class Node < ArvadosModel
           # Typically, this is used to trigger a dns server restart
           f.puts Rails.configuration.dns_server_reload_command
         end
-      rescue => e
+      rescue IOError, SystemCallError => e
         logger.error "Unable to write #{restartfile}: #{e.message}"
         ok = false
       end