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Network node

Networking in OpenStack

  • Project name neutron
  • Rich tenant-facing API to defining network connectivity and addressing in the cloud
  • Supports each tenant having isolated:
    • multiple private networks
    • IP addressing scheme (can overlap with those used by other tenants)

Networking API resources

  • Network:
    • L2 segment like VLAN in a physical world
  • Subnet:
    • IPv4 and IPv6 IP address block and config
  • Port:
    • Connection point between a vNIC and a virtual network
    • Also describes associated network config (MAC, IP)

Plugins

  • Original Compute network implementation (nova-network):
    • isolation through Linux VLANs and iptables
  • neutron introduces plug-in concept:
    • Pluggable back-end implementation of the OpenStack Networking APIs:
      • VLANs and iptables
      • L2-in-L3 tunneling
      • OpenFlow, etc.

Current Set of Plugins

Complete list of supported plugins https://wiki.openstack.org/wiki/Neutron_Plugins_and_Drivers

colleft

  • Big Switch
  • Brocade
  • Cisco
  • CloudBase Hyper-V
  • IBM SDN-VE
  • Linux Bridge

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  • Midonet
  • ML2 (Modular Layer 2)
  • NEC OpenFlow
  • Open vSwitch
  • PLUMgrid
  • VMware NSX

Note

Plugin list taken from: http://docs.openstack.org/admin-guide/networking_config-plugins.html

Components of OpenStack Networking

neutron-server

  • Requires access to a database for persistent storage
  • Can co-exist with controller or separately
  • Requires additional agents

Networking Agents

  • plugin agent (neutron- * -agent): runs on each hypervisor
  • dhcp agent (neutron-dhcp-agent): provides DHCP services
  • l3 agent (neutron-l3-agent): provides L3/NAT forwarding (external network access)
  • Agents communicate through RPC (e.g. RabbitMQ) and/or API
  • Great flexibility how to deploy neutron services, plugins and agents

Note

  • plugin agent (neutron- * -agent):Runs on each hypervisor to perform local vswitch configuration. Agent to be run depends on which plug-in you are using, as some plug-ins do not require an agent
  • dhcp agent (neutron-dhcp-agent):Provides DHCP services to tenant networks,this agent is the same across all plug-ins
  • l3 agent (neutron-l3-agent):Provides L3/NAT forwarding to provide external network access for VMs on tenant networks. This agent is the same across all plug-ins

Network Types

Typically at least four distinct physical data center networks:

  • Management network: internal communication between OpenStack Components.
  • Data network: VM data communication within the cloud deployment.
  • External network: provide VMs with Internet access.
  • API network: exposes all OpenStack APIs.

Note

  • Management network: Used for internal communication between OpenStack Components. The IP addresses on this network should be reachable only within the data center.
  • Data network: Used for VM data communication within the cloud deployment. The IP addressing requirements of this network depend on the OpenStack Networking plug-in in use.
  • External network: Used to provide VMs with Internet access, in some deployment scenarios. The IP addresses on this network should be reachable by anyone on the Internet.
  • API network: Exposes all OpenStack APIs, including the OpenStack Networking API, to tenants. The IP addresses on this network should be reachable by anyone on the Internet. This may be the same network as the external network, as it is possible to create a subnet for the external network that uses IP allocation ranges to use only less than the full range of IP addresses in an IP block.

OpenStack Networking - Connectivity

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OpenStack Networking Concepts

  • Tenant networks, provider networks
  • Tenant network types:
    • Local: within single host
    • Flat: no network segmentation, single broadcast domain
    • VLAN: VLAN for segmentation
    • VXLAN, GRE: Overlay networks, tunnels encapsulate network traffic

OpenStack Networking Concepts (cont)

  • Namespaces:
    • Each network creates and unique namespace “netns”
    • netns hosts an interface and IP addresses for dnsmasq and the neutron-ns-metadata-proxy
  • Metadata:
    • Not all networks or VMs need metadata access.
    • Create the subnet without specifying a gateway IP and with a static route from 0.0.0.0/0 to your gateway IP address
  • OVS Bridge:
    • Isolate the traffic

OpenStack Networking Concepts (cont)

image

Managing Networks - CLI

Networks:

  • neutron ext-list -c alias -c name (list network extensions)
  • neutron net-create net1
  • neutron net-create net2 --provider:network-type local

Subnets:

  • neutron subnet-create net1 192.168.2.0/24 --name subnet1 (name, CIDR, subnet name – optional)

Managing Networks - CLI

Routers:

  • To provider net: neutron router-gateway-set ROUTER NETWORK
  • To subnet: neutron router-interface-add ROUTER SUBNET

Ports:

  • neutron port-create net1 --fixed-ip ip_address=192.168.2.40
  • neutron port-create net1 (without fix ip)
  • Query ports: neutron port-list --fixed-ips
    • neutron port-list --fixed-ips ip_address=10.0.0.4