The document summarizes new features in Neutron for the Juno release, including improvements to achieve parity with Nova networking functionality, the addition of distributed virtual routing to improve scalability, L3 high availability using VRRP, full IPv6 support, and enhancements to security group implementation and communication between agents and servers.

1. Neutron Juno Release
Barcelona OpenStack MeetUp Group

2. What’s New in Neutron for Juno
•Nova Network Parity
•Distributed Virtual Router
•L3 HA
•IPv6
•Security Group Enhancements
•Plugin Specific improvements
•Bug-fixes
Full list of release issues here
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3. Nova Network Parity
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Nova Network Parity
Problem: Neutron does not offer same functionality as nova-network
does, and sometimes is doing worse.
• Quick summary: technical debt in Neutron no allowed anymore.
• Neutron migration DB: each plugin offers different database schema and
migration depends on services enabled.
– New service enabled can end up with migration error.
– Grenade project hates Neutron project.
– No way to migrate from one vendor plugin to another.
• Neutron does not scale (L3 bottleneck). Nova-network does.
• No way to migrate from nova-network to Neutron
• Current users in nova networks do API calls that does not exist in Neutron

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Nova Network Parity
Solutions
• Heal Script. All tables from all plugins and services added.
• Scalability issues improved by DVR and L3 HA
developments (more about this later)
• Tempest tests added
• Gate tests added
•Neutron default in devstack (not yet, devstack is not part of
the integrated release)
•Nova-network to Neutron migration script (not yet!)
•Missing API calls (get_fixed_ips, get_vifs_by_vm) (in
development!)

6. Distributed Virtual Router (DVR)
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Distributed Virtual Router (DVR)
Problem: Neutron does not scale
• Until Icehouse, Network Node is unique in installation:
– Single point of failure
– Traffic bottleneck

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Distributed Virtual Router (DVR)
Solution: delegate DNAT floating IP/fixed private IP to compute
nodes
• Traffic to floating Ips managed directly to compute nodes

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Distributed Virtual Router (DVR)
Solution: Handle East-West traffic inside compute L3
namespace
● One namespace per tenant in compute machine
● Router inside namespace has an ARP table of the other tenant networks MAC
addresses

10. Distributed Virtual Router (DVR)
No solution: SNAT
● North/South traffic without Floating IPs
• Remains as a Single Point of Failure and traffic bottleneck (without L3 HA)

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Distributed Virtual Router (DVR)
Summary
• Significant improvement in traffic bottleneck
•Maybe now Neutron finally scales more than nova-network
• Best option for new deployments
• Upgrades (IMHO): pain in the ass
– Database migration not provided from legacy to DVR ¿?
– L3 agents must be configured and installed manually
– Compute nodes need access to external network
• SNAT needs to be improved (more later in L3 HA)

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Distributed Virtual Router (DVR)
More info
● Base design document
● L2 agent changes
● L3 agent changes
● Atlanta Summit Slides
● OpenStack wiki: How to enable DVR
● Official Spec

13. L3 High Availability
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L3 High Availability
Problem: L3 SNAT con not be distributed
● To provide internet access to Virtual Machines
without HA, you need a SNAT service:
– A single gateway per network by default (even 2
gateways does not solve the problem)
– This gateway must keep track of outgoing
connections to redirect reverse-SNAT ingoing
responses.
● Single point of failure: All machines accessing to
internet lose their connections if Network Node
fails.

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L3 High Availability
Solution: based on VRRP protocol
● First Hop Redundancy Protocol (FHRP)
● Multiple nodes working as router of the network.
● Work on master (active) or slave (stand-by) mode
● If master does not send 'hello' messages to stand-by
nodes, they start an election process to define
the new master
● Active node maps a configured VIP – MAC address
that is the gateway of the Vms subnets

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L3 High Availability
Solution: based on VRRP protocol

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L3 High Availability
Solution: VRRP in Neutron
● An HA Network is created (tenant Network without tenant id)
● Keepalived traffic is sent by this network

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L3 High Availability
More info
● Assaf Muller blog
● Official Spec
● How to test
● OpenStack Wiki

19. IPv6
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IPv6
Icehouse status
● IPv6 networks, although posible, almost useless
– Only Link-Local addresses registered in Neutron
– RA advertiser for SLAAC support must be
deployed manually
● Only one attribute in the subnet:
– ip_version

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IPv6
Juno status
● Full support to IPv6 tenant networks
● RADVD and DNSMASQ services deployed depending on the
attributes
● Current attributes:
– ip_version
– ipv6_ra_mode
– ipv6_address_mode
● These previous attributes allow provider services to pass through
the network tenant router and offer provider hardware solutions
● Next slide shows all the combinations available
● Public networks not yet (current floating IP NAT does not make
sense in IPv6)

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IPv6
More info
● Spec: upstream SLAAC support
● Spec: Router Advertiser Daemon (radvd)
● Spec: Stateful and Stateless mode in dnsmasq
● Patch to deploy a devstack with IPv6

24. Security Groups Enharcements
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Security Group Enharcements
*Image stolen miserably from rackspace
documentation

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Security Group Enharcements
Implementation improvements
● Using Ipset improves the readability and scalability of iptables chains:

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Security Group Enharcements
Implementation Improvements
● Problem: Communication L2 Agent – Neutron Server regarding security
groups does not scale:
– RCP calls block communication channel
– Call by device
– Long messages from Server (20-600MB!!)
● Solution: Response based on security group aggregated information:
– Easy to fetch from Neutron
– Smaller messages
– Example

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Security Group Enharcements
More info
● Ipsec spec
● Security Group RPC calls improvement spec

29. Demo time!
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More info
● Release Notes
● Kyle Mestery notes
● Juno design specs
● Technical's Comitee Neutron Gap Coverage
● Launchpad report

31. Thank you
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