VLAN Networking OpenStack

Introduction

Here, We will look at how to setup a network (based on VLAN). Connect VM instances to these networks. Make necessary configurations so that VM's can communicate with each other across different networks. We also try to figure out how the Linux Bridge is setup as we configure the Network and the Virtual Machines.

This would be extended later using an external switch/router in the subsequent blog.

Read this blog to understand about Linux Network Namespaces

Create Network.

Created a new network named "application_net" having subnet "103.103.103.0/24" and gateway ip address as "103.103.103.1". VM's created on this network would have ip address allocated from this subnet.

user@os-157:~$ neutron net-create application_net Created a new network: +----------------+--------------------------------------+ | Field | Value | +----------------+--------------------------------------+ | admin_state_up | True | | id | 5cc1629c-7d97-4323-a92c-42ccd6d0dfe5 | | name | application_net | | shared | False | | status | ACTIVE | | subnets | | | tenant_id | d8fde3204bbd43258cb0e1bb5ee2502e | +----------------+--------------------------------------+ user@os-157:~$ neutron subnet-create application_net 103.103.103.0/24 --name application_sub --gateway 103.103.103.1 Created a new subnet: +------------------+------------------------------------------------------+ | Field | Value | +------------------+------------------------------------------------------+ | allocation_pools | {"start": "103.103.103.2", "end": "103.103.103.254"} | | cidr | 103.103.103.0/24 | | dns_nameservers | | | enable_dhcp | True | | gateway_ip | 103.103.103.1 | | host_routes | | | id | 99e0f713-0024-45d8-8f50-c4d74379faf8 | | ip_version | 4 | | name | application_sub | | network_id | 5cc1629c-7d97-4323-a92c-42ccd6d0dfe5 | | tenant_id | d8fde3204bbd43258cb0e1bb5ee2502e | +------------------+------------------------------------------------------+

List the Network and Subnet details.

Use neutron commands to see the created and network and subnet-details.

user@os-157:~$ neutron net-list +--------------------------------------+-----------------+-------------------------------------------------------+ | id | name | subnets | +--------------------------------------+-----------------+-------------------------------------------------------+ | 5cc1629c-7d97-4323-a92c-42ccd6d0dfe5 | application_net | 99e0f713-0024-45d8-8f50-c4d74379faf8 103.103.103.0/24 | +--------------------------------------+-----------------+-------------------------------------------------------+ user@os-157:~$ neutron subnet-list +--------------------------------------+-----------------+------------------+------------------------------------------------------+ | id | name | cidr | allocation_pools | +--------------------------------------+-----------------+------------------+------------------------------------------------------+ | 99e0f713-0024-45d8-8f50-c4d74379faf8 | application_sub | 103.103.103.0/24 | {"start": "103.103.103.2", "end": "103.103.103.254"} | +--------------------------------------+-----------------+------------------+------------------------------------------------------+

Create two Virtual Machines  connected to the Network.

Create two VM's "app_1" and "app_2" connected to this newly created Network "application_net"

nova boot --flavor 1 --image b072e4b1-ea4e-4e3f-8741-6bce8f34eb40 --security_group default app_1 nova boot --flavor 1 --image b072e4b1-ea4e-4e3f-8741-6bce8f34eb40 --security_group default app_2

Bridge details and Network Topology.

Let's see what all has happened under the hood.

A new bridge(Linux Bridge) is created by the name "brq5cc1629c-7d" and there are tap/veth interfaces that gets attached to the bridge.There is tap interface for that gets attached to the bridge for every VM in the network.(application_net)

user@os-157:~$ brctl show bridge name bridge id STP enabled interfaces brq5cc1629c-7d 8000.aa1c8f3ee486 no eth1.85 tap0f9f4744-3f tap7ed0efa1-d1 tapdfcfc52e-66

Communication between two VM's

The two VM's app_1 and app_2 will be able to ping each other, as they are on the same network (application_network)

Ping between VM's in application_net

Create another network and VMs

Lets create another network "db_net" with  VMS "db_1" and "db_2"  in that network.

These two VM's would be able to talk to each other. (as they are on the same Linux bridge).

Communication between VM's between the two networks

VM (app_1) in application_network will not be able to ping VM(db_1) in db_network.
In order to achieve such a communication, the two bridges should be connected to a router(Physical/Virtual)

user@os-157:~$ neutron router-interface-add router1 56d0c029-c9db-457f-968f-de9148a7756e Added interface c86010bd-e4b8-4686-b031-100321489d32 to router router1. neutron router-interface-add router1 99e0f713-0024-45d8-8f50-c4d74379faf8 Added interface c6283960-5d3f-46a7-b132-f836952a0d9c to router router1. user@os-157:~$ sudo ip netns exec qrouter-7ce1bc78-ae3f-488f-8dc8-f1869bd905d4 ifconfig lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) qg-82c8613e-77 Link encap:Ethernet HWaddr fa:16:3e:cf:ca:3b inet addr:172.24.4.226 Bcast:172.24.4.239 Mask:255.255.255.240 inet6 addr: fe80::f816:3eff:fecf:ca3b/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:2534 errors:0 dropped:2405 overruns:0 frame:0 TX packets:15 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:595684 (595.6 KB) TX bytes:846 (846.0 B) qr-c6283960-5d Link encap:Ethernet HWaddr fa:16:3e:a7:e4:12 inet addr:103.103.103.1 Bcast:103.103.103.255 Mask:255.255.255.0 inet6 addr: fe80::f816:3eff:fea7:e412/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:22 errors:0 dropped:1 overruns:0 frame:0 TX packets:9 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:5052 (5.0 KB) TX bytes:594 (594.0 B) qr-c86010bd-e4 Link encap:Ethernet HWaddr fa:16:3e:27:58:6b inet addr:15.15.15.1 Bcast:15.15.15.255 Mask:255.255.255.0 inet6 addr: fe80::f816:3eff:fe27:586b/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:25 errors:0 dropped:2 overruns:0 frame:0 TX packets:9 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:5391 (5.3 KB) TX bytes:594 (594.0 B)

Once the two bridges are connected to the router, the two VMS (from different networks) would be able to ping each other.