design-network.rst

Network management

gnt-network add --network=192.0.2.0/24 --gateway=192.0.2.1 \
               --v6-network=2001:648:2ffc::/64 --v6-gateway=2001:648:2ffc::1 \
               public

gnt-network reserve-ips public 192.0.2.2 192.0.2.10-192.0.2.20

gnt-network connect public nodegroup1 link100
gnt-network connect public nodegroup2 link200
gnt-network disconnect public nodegroup1 (only permitted if no instances are
                                          currently using this network in the group)

gnt-network list
 Name          IPv4 Network    IPv4 Gateway          IPv6 Network                 IPv6Gateway
 public                 192.0.2.0/24   192.0.2.1       2001:db8:dead:beef::/64         2001:db8:dead:beef::1
 private        10.0.1.0/24       -                     -                              -

gnt-network list-connected
 Network       Node Group      Link
 public                nodegroup1      link100
 public                nodegroup2      link200
 private       nodegroup1      link50

gnt-network list-connected private
 Network       Node Group      Link
 private       nodegroup1      link50

gnt-network info public
 Name: public
 IPv4 Network: 192.0.2.0/24
 IPv4 Gateway: 192.0.2.1
 IPv6 Network: 2001:db8:dead:beef::/64
 IPv6 Gateway: 2001:db8:dead:beef::1
 Connected to: nodegroup1 (link100), nodegroup2 (link200)
 Total IPv4 count: 256
 Free address count: 201 (80% free)
 IPv4 pool status: XXX.........XXXXXXXXXXXXXX...XX.............
                   XXX..........XXX...........................X
                   ....XXX..........XXX.....................XXX
                                           X: occupied  .: free
 Used by 22 instances:
  inst1
  inst2
  inst32
  ..

NIC "network" parameter

1. "network" takes precedence over "link"
2. manually setting "link" on a nic with existing "network" is not permitted
3. as a safety guard, setting a "network" parameter on a nic with a "link" is only permitted if the network's link on the instance's node group is the same as the current nic's link
4. "link" is updated on startup according to the network -> nodegroup mapping

Default nic "network" parameter add default "network" argument? How do we deal with transitions? -> network and link may not be set at the same time -> setting network will unset link and vice-versa -> setting network is only permitted iff:

all NICs with a "default" link would result in having the same link right after setting "network".

i.e.: for instance in all_instances:

for nic in instance.nics:

if nic.link == instance.primary_node.group.networks[network]:

...

else:

raise errors.OpPrereqError

IAllocator changes

• Make it network-aware, same as storage-aware
• Both, network and storage will act as constraints, i.e. "place me a node that has access to network x and storage pool y on the cluster". The iallocator will thus rule out node groups based on these constraints.

Helper methods in lib/config.py

• ConfigWriter.GetInstancesByNodeGroup(group_uuid)
• ConfigWriter.GetInstancesInfoByNodeGroup(group_uuid)