nova-manage : create network crashes when subnet range provided is not enough

[Tushar Patil]

If I run network create command with insufficient subnet range, then it crashes in middle. It seems like fixed_ip range check is not implemented.

$/usr/local/bin/nova-manage --flagfile=/etc/nova/nova.conf network create 10.0.0.0/28 2 64

Fixed_ips range:10.0.0.0/28
number of networks=2
network size per network=64

Error Reported on Console
----------------------------------
2011-02-07 11:18:15,879 INFO sqlalchemy.orm.mapper.Mapper [-] (Project|projects) _post_configure_properties() complete
2011-02-07 11:18:16,008 CRITICAL nova.root [-]
(nova.root): TRACE: Traceback (most recent call last):
(nova.root): TRACE: File "/usr/local/bin/nova-manage", line 5, in <module>
(nova.root): TRACE: pkg_resources.run_script('nova==2011.1', 'nova-manage')
(nova.root): TRACE: File "/usr/lib/python2.6/dist-packages/pkg_resources.py", line 461, in run_script
(nova.root): TRACE: self.require(requires)[0].run_script(script_name, ns)
(nova.root): TRACE: File "/usr/lib/python2.6/dist-packages/pkg_resources.py", line 1194, in run_script
(nova.root): TRACE: execfile(script_filename, namespace, namespace)
(nova.root): TRACE: File "/usr/local/lib/python2.6/dist-packages/nova-2011.1-py2.6.egg/EGG-INFO/scripts/nova-manage", line 694, in <module>
(nova.root): TRACE: main()
(nova.root): TRACE: File "/usr/local/lib/python2.6/dist-packages/nova-2011.1-py2.6.egg/EGG-INFO/scripts/nova-manage", line 686, in main
(nova.root): TRACE: fn(*argv)
(nova.root): TRACE: File "/usr/local/lib/python2.6/dist-packages/nova-2011.1-py2.6.egg/EGG-INFO/scripts/nova-manage", line 500, in create
(nova.root): TRACE: vpn_start=int(vpn_start))
(nova.root): TRACE: File "/usr/local/lib/python2.6/dist-packages/nova-2011.1-py2.6.egg/nova/network/manager.py", line 536, in create_networks
(nova.root): TRACE: cidr = "%s/%s" % (fixed_net[start], significant_bits)
(nova.root): TRACE: File "/usr/lib/pymodules/python2.6/IPy.py", line 880, in getitem
(nova.root): TRACE: return IP(IPint.getitem(self, key))
(nova.root): TRACE: File "/usr/lib/pymodules/python2.6/IPy.py", line 561, in getitem
(nova.root): TRACE: raise IndexError?
(nova.root): TRACE: IndexError?
(nova.root): TRACE:

[Thierry Carrez (ttx)]

Ricardo: did you start working on that ? If yes, please set this to "In progress" and link any branch you may have. If not, maybe unassign you to give someone else a chance to take it ?

[Ricardo Carrillo Cruz (rcarrillocruz)]

Stack trace is different from the original bug poster:

root@dormammu-VirtualBox:/home/dormammu/src/nova/lp715424/bin# ./nova-manage network create 10.0.0.0/28 2 64
2011-02-21 21:36:52,452 CRITICAL nova.root [-]
(nova.root): TRACE: Traceback (most recent call last):
(nova.root): TRACE: File "./nova-manage", line 746, in <module>
(nova.root): TRACE: main()
(nova.root): TRACE: File "./nova-manage", line 738, in main
(nova.root): TRACE: fn(*argv)
(nova.root): TRACE: File "./nova-manage", line 532, in create
(nova.root): TRACE: label=label)
(nova.root): TRACE: File "/home/dormammu/src/nova/lp715424/nova/network/manager.py", line 532, in create_networks
(nova.root): TRACE: cidr = "%s/%s" % (fixed_net[start], significant_bits)
(nova.root): TRACE: File "/usr/lib/pymodules/python2.6/IPy.py", line 880, in __getitem__
(nova.root): TRACE: return IP(IPint.__getitem__(self, key))
(nova.root): TRACE: File "/usr/lib/pymodules/python2.6/IPy.py", line 561, in __getitem__
(nova.root): TRACE: raise IndexError
(nova.root): TRACE: IndexError
(nova.root): TRACE:
root@dormammu-VirtualBox:/home/dormammu/src/nova/lp715424/bin# ./nova-manage network list
network netmask start address DNS
10.0.0.0/27 255.255.255.224 10.0.0.3 None
10.0.0.0/26 255.255.255.192 10.0.0.3 None
10.0.0.0/26 255.255.255.192 10.0.0.3 None
10.0.0.0/24 255.255.255.0 10.0.0.3 None
10.0.1.0/24 255.255.255.0 10.0.1.3 None
10.0.0.0/26 255.255.255.192 10.0.0.3 None
10.0.0.0/26 255.255.255.192 10.0.0.3 None
10.0.0.0/26 255.255.255.192 10.0.0.3 None

Anyways, truth is the networks are added despite the trace, we need to check for overlapping existing networks.

[Ricardo Carrillo Cruz (rcarrillocruz)]

Dig into IPy documentation, looks like IP.len() might do the trick, that gives the amount of hosts for a given CIDR network.
For example:

>>> ip = IPy.IP("10.0.0.0/28")
>>> print ip.len()
16

It would be a matter of making sure fixed_net.len() can fit num_networks * network_size .