added new class Instances for managaging instances

added new method list in class Instances:

# nova-manage instance list
instance node type state launched image kernel ramdisk project user zone index
i-00000547 XXXXXXX m1.small running 2011-02-18 08:36:37 ami-a03ndz0q ami-0isqekvw testing berendt None 0
i-00000548 XXXXXXX m1.small running 2011-02-18 08:37:17 ami-a03ndz0q ami-0isqekvw testing berendt None 1
i-00000549 XXXXXXX m1.small running 2011-02-18 08:37:52 ami-a03ndz0q ami-0isqekvw testing berendt None 2

# nova-manage instance list ares
instance   node            type       state      launched            image        kernel       ramdisk       project    user       zone       index
i-00000c1c ares            m1.tiny    running    2011-02-26 22:51:40 ami-pus9dj84 ami-zhcv0yyx ami-av96fu30  testing    berendt    None       1    

extended the method list in class FixedIps to lookup ip addresses assigned to a specified node:

# nova-manage fixed list ares
network           	IP address     	MAC address      	hostname       	host
192.168.3.0/24    	192.168.3.6    	02:16:3e:75:d7:9a	i-00000c1c     	ares

1 files changed, 57 insertions, 8 deletions

diff --git a/bin/nova-manage b/bin/nova-manage
index 2b42dfff5..a4d820209 100755
--- a/bin/nova-manage
+++ b/bin/nova-manage
@@ -446,10 +446,15 @@ class FixedIpCommands(object):
     def list(self, host=None):
         """Lists all fixed ips (optionally by host) arguments: [host]"""
         ctxt = context.get_admin_context()
-        if host == None:
-            fixed_ips = db.fixed_ip_get_all(ctxt)
-        else:
-            fixed_ips = db.fixed_ip_get_all_by_host(ctxt, host)
+
+        try:
+            if host == None:
+                fixed_ips = db.fixed_ip_get_all(ctxt)
+            else:
+                fixed_ips = db.fixed_ip_get_all_by_host(ctxt, host)
+        except exception.NotFound as ex:
+            print "error: %s" % ex
+            sys.exit(2)
 
         print "%-18s\t%-15s\t%-17s\t%-15s\t%s" % (_('network'),
                                                   _('IP address'),
@@ -466,9 +471,9 @@ class FixedIpCommands(object):
                 host = instance['host']
                 mac_address = instance['mac_address']
             print "%-18s\t%-15s\t%-17s\t%-15s\t%s" % (
-                                  fixed_ip['network']['cidr'],
-                                  fixed_ip['address'],
-                                  mac_address, hostname, host)
+                    fixed_ip['network']['cidr'],
+                    fixed_ip['address'],
+                    mac_address, hostname, host)
 
 
 class FloatingIpCommands(object):
@@ -716,6 +721,49 @@ class DbCommands(object):
         print migration.db_version()
 
 
+class InstanceCommands(object):
+    """Class for managing instances."""
+
+    def list(self, host=None, instance=None):
+        """Show a list of all instances"""
+        print "%-10s %-15s %-10s %-10s %-19s %-12s %-12s %-12s" \
+              "  %-10s %-10s %-10s %-5s" % (
+            _('instance'),
+            _('node'),
+            _('type'),
+            _('state'),
+            _('launched'),
+            _('image'),
+            _('kernel'),
+            _('ramdisk'),
+            _('project'),
+            _('user'),
+            _('zone'),
+            _('index'))
+
+        if host == None:
+            instances = db.instance_get_all(context.get_admin_context())
+        else:
+            instances = db.instance_get_all_by_host(
+                           context.get_admin_context(), host)
+
+        for instance in instances:
+            print "%-10s %-15s %-10s %-10s %-19s %-12s %-12s %-12s" \
+                  "  %-10s %-10s %-10s %-5d" % (
+                instance['hostname'],
+                instance['host'],
+                instance['instance_type'],
+                instance['state_description'],
+                instance['launched_at'],
+                instance['image_id'],
+                instance['kernel_id'],
+                instance['ramdisk_id'],
+                instance['project_id'],
+                instance['user_id'],
+                instance['availability_zone'],
+                instance['launch_index'])
+
+
 class VolumeCommands(object):
     """Methods for dealing with a cloud in an odd state"""
 
@@ -1002,7 +1050,8 @@ CATEGORIES = [
     ('volume', VolumeCommands),
     ('instance_type', InstanceTypeCommands),
     ('image', ImageCommands),
-    ('flavor', InstanceTypeCommands)]
+    ('flavor', InstanceTypeCommands),
+    ('instance', InstanceCommands)]
 
 
 def lazy_match(name, key_value_tuples):