Add support for migrating VMs to pool_manager.

This commit adds a capability to pool_manager to migrate VMs placed in the migrating queue. When a VM is checked out an entry is created in vmpooler__migrating. The existing process for evaluating VM states executes the migrate_vm method for the provided VM, and removes it from the queue. The least used compatible host for the provided VM is selected and, if necessary, a migration to the lesser used host is performed. Migration time and time from the task being queued until completion are both tracked with the redis VM object in 'migration_time' and 'checkout_to_migration'. The migration time is logged in the vmpooler.log, or the VM is reported as not requiring migration. Without this change VMs are not evaluated for checkout at request time.

lib/vmpooler/pool_manager.rb

@@ -455,6 +455,31 @@ def _check_snapshot_queue
       end
     end
 
+    def migrate_vm(vm, pool)
+      Thread.new do
+        _migrate_vm(vm, pool)
+      end
+    end
+
+    def _migrate_vm(vm, pool)
+      $redis.srem('vmpooler__migrating__' + pool, vm)
+      vm_object = $vsphere[pool].find_vm(vm) || $vsphere[pool].find_vm_heavy(vm)
+      host = $vsphere[pool].find_least_used_compatible_host(vm_object)
+      parent_host = vm_object.summary.runtime.host
+      parent_host_name = parent_host.name
+      if host == parent_host
+        $logger.log('s', '[ ] [' + pool + "] No migration required for '" + vm + "'")
+      else
+        start = Time.now
+        $vsphere[pool].migrate_vm_host(vm_object, host)
+        finish = '%.2f' % (Time.now - start)
+        checkout_to_migration = '%.2f' % (Time.now - Time.parse($redis.hget('vmpooler__vm__' + vm, 'checkout')))
+        $redis.hset('vmpooler__vm__' + vm, 'migration_time', finish)
+        $redis.hset('vmpooler__vm__' + vm, 'checkout_to_migration', checkout_to_migration)
+        $logger.log('s', "[>] [#{pool}] '#{vm}' migrated from #{parent_host_name} to #{host.name} in #{finish} seconds")
+      end
+    end
+
     def check_pool(pool)
       $logger.log('d', "[*] [#{pool['name']}] starting worker thread")
 
@@ -480,7 +505,8 @@ def _check_pool(pool)
             (! $redis.sismember('vmpooler__ready__' + pool['name'], vm['name'])) &&
             (! $redis.sismember('vmpooler__pending__' + pool['name'], vm['name'])) &&
             (! $redis.sismember('vmpooler__completed__' + pool['name'], vm['name'])) &&
-            (! $redis.sismember('vmpooler__discovered__' + pool['name'], vm['name']))
+            (! $redis.sismember('vmpooler__discovered__' + pool['name'], vm['name'])) &&
+            (! $redis.sismember('vmpooler__migrating__' + pool['name'], vm['name']))
 
             $redis.sadd('vmpooler__discovered__' + pool['name'], vm['name'])
 
@@ -555,6 +581,17 @@ def _check_pool(pool)
         end
       end
 
+      # MIGRATIONS
+      $redis.smembers('vmpooler__migrating__' + pool['name']).each do |vm|
+        if inventory[vm]
+          begin
+            migrate_vm(vm, pool['name'])
+          rescue
+            $logger.log('s', '[x] [' + pool['name'] + "] '" + vm + "' failed to migrate")
+          end
+        end
+      end
+
       # REPOPULATE
       ready = $redis.scard('vmpooler__ready__' + pool['name'])
       total = $redis.scard('vmpooler__pending__' + pool['name']) + ready