Introduction to Neutron

# Introduction to Openstack Neutron

# Agenda

1. What is Neutron?
  * what is it for in Openstack world?
  * overview
2. Neutron server in details:
  * functions of Neutron server
  * main components of Neutron server
3. Neutron agents:
  * L2 agents (openvswitch, linuxbridge, etc.),
  * L3 agent,
  * metadata, dhcp agents.
4. Basic concepts in Neutron
5. Examples of usage Neutron CLI client
6. Standard workflow between Nova and Neutron
7. Network scenario example

---

# Neutron in Openstack world

![openstack_architecture](images/openstack-software-diagram.png)  
source: http://www.openstack.org/software

### Neutron is Networking as a Service for Openstack

???
From openstack wiki:
Neutron is an OpenStack project to provide "networking as a
service" between interface devices (e.g., vNICs) managed by other Openstack
services (e.g., nova).

---

# Neutron main components

![architecture](images/components_architecture_server.png)

---

# Neutron server functions

---

# Neutron server components

.left_side_list[
* Core plugin - for example ML2 with drivers for openvswitch, linuxbridge and/or SR-IOV
]

.left_side_list[
* API extenstions - used to add custom REST API functions, list of enabled extenstions can be checked via API call:
]

---

# Neutron agents

## L2 agent

![architecture](images/components_architecture_l2agent.png)

---

# Neutron agents

## L2 agent

---

# Neutron agents

## L3 agent

![architecture](images/components_architecture_l3agent.png)

---

# Neutron agents

## L3 agent

.left_side_list[
* uses standard Linux tools:
  * standard Linux IP stack,
  * iptables (NAT),
  * network namespaces to provide isolated routers
]

---

# Neutron agents

## DHCP and Metadata agent

![architecture](images/components_architecture_dhcp_metadata.png)

---

# Neutron agents

## DHCP and Metadata agent

.left_side_list[
* Metadata agent provides proxy between instances and nova-api metadata service
  and provides metadata service for instances on 169.254.169.254:80
]

---

# Basic concepts in Neutron

.left_side_list[
* network - isolated L2 network segment, like VLAN in physical networking world
  * tenant network - private network used in tenant, it can be done with VXLAN or GRE tunneling
  * provider network - mapped directly to physical network in datacenter; it can be VLAN or flat network
  * external network - like provider network but also provide access to internet
]

.left_side_list[
* subnet - block of IPv4 or IPv6 addresses with configuration like dhcp server IP, gateway IP address, static routes
]

---

# Basic concepts in Neutron

.left_side_list[
* port - connection point for attaching a single device, such as the NIC of a instance, to a virtual network
]

.left_side_list[
* static IP - IP address assigned to port and configured for example on instance
* floating IP - public IP address, configured on router and routed (NAT) to some static IP address;
  it is not configured on instance directly and can be easily moved to another instance
]

---

# CLI client usage

---

# CLI client usage

```
admin@devstack-1:~$ neutron subnet-create Local-Network 10.0.0.0/24
Created a new subnet:
+-------------------+--------------------------------------------+
| Field             | Value                                      |
+-------------------+--------------------------------------------+
| allocation_pools  | {"start": "10.0.0.2", "end": "10.0.0.254"} |
| cidr              | 10.0.0.0/24                                |
| created_at        | 2016-08-01T12:47:28                        |
| description       |                                            |
| dns_nameservers   |                                            |
| enable_dhcp       | True                                       |
| gateway_ip        | 10.0.0.1                                   |
| host_routes       |                                            |
| id                | 9f31692e-f2b8-4db0-9073-1c732373b9af       |
| ip_version        | 4                                          |
| ipv6_address_mode |                                            |
| ipv6_ra_mode      |                                            |
| name              |                                            |
| network_id        | 74149489-5cd6-473e-aeb7-d003652c8048       |
| subnetpool_id     |                                            |
```

---

# CLI client usage

```
admin@devstack-1:~$ nova boot --image cirros-0.3.4-i386-disk \
--nic net-id=74149489-5cd6-473e-aeb7-d003652c8048 --flavor m1.micro VM-1
+--------------------------------------+----------------------------------------+
| Property                             | Value                                  |
+--------------------------------------+----------------------------------------+
| OS-DCF:diskConfig                    | MANUAL                                 |
| accessIPv4                           |                                        |
| accessIPv6                           |                                        |
| adminPass                            | U9h5cGcnZ2tm                           |
| created                              | 2016-08-01T12:51:11Z                   |
| flavor                               | m1.micro (84)                          |
| id                                   | e4d99f99-f189-4b6a-b37d-ec1f0e106e7d   |
| image                                | cirros-0.3.4-i386-disk                 |
| key_name                             | -                                      |
| locked                               | False                                  |
| metadata                             | {}                                     |
| name                                 | VM-1                                   |
| os-extended-volumes:volumes_attached | []                                     |
| security_groups                      | default                                |
| status                               | BUILD                                  |
```

---

# Standard workflow between Nova and Neutron

.left_side_list[
* nova-compute is spawning instance on compute node and call Neutron API to
  create new port (like neutron port-create ...)
]

![workflow_1](images/workflow_1.png)

---

# Standard workflow between Nova and Neutron

.left_side_list[
* neutron-server creates port in desired network, allocate IP for this port and try
  to bind port with one of enabled mechanism drivers
]

![workflow_1](images/workflow_2.png)

---

# Standard workflow between Nova and Neutron

.left_side_list[
* nova-compute receives from Neutron informations about new port and prepare
  to connect tap device (e.g. create bridge)
* neutron-server notify L2 agent and DHCP agent about new port
* nova-compute starts instances and pause it for a while
]

![workflow_1](images/workflow_3.png)

---

# Standard workflow between Nova and Neutron

.left_side_list[
* Neutron L2 agent connects port to L2 network (vlan tagging, openflow rules, etc.) and notify neutron-server that port is ACTIVE
* neutron-server notify nova-api that port for instance is ready, nova-compute can then unpause instance
]

![workflow_1](images/workflow_4.png)

---

#Network scenario example

![scenario overview](images/scenario-legacy-general.png)

---

#Network scenario example

.left_image[
![scenario compute 1](images/scenario-legacy-ovs-compute1.png)
]
.right_image[
![scenario compute 2](images/scenario-legacy-ovs-compute2.png)
]

---

#Network scenario example

.left_image[
![scenario network 1](images/scenario-legacy-ovs-network1.png)
]
.right_image[
![scenario network 2](images/scenario-legacy-ovs-network2.png)
]

---

#Network scenario example

---

#Network scenario example

---

# Questions?

## Do You want to build Openstack clouds?

## Reference

* https://wiki.openstack.org/wiki/Neutron
* http://docs.openstack.org/liberty/networking-guide/deploy.html
* http://slawqo.github.io/introduction_to_neutron/