OpenShift SDN - Meetupfiles.meetup.com/16609572/OpenShift SDN.pdf · OpenShift automates the Docker image build process with Source-to-Image (S2I). S2I combines source code with a

OpenShift SDNHow OpenShift Networking helps to automate

Ilkka Tengvall ([email protected])Solution Architect, Red HatApril, 2016

Understand what OpenShift network benefits and how to use it

● What problem are we trying to solve?● What are the advantages of the solution?

Agenda

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Container cluster network might be messy

3

But it doesn’t need to be

How do we do that with SDN?Add a layer of confusion abstraction!

4

DEMO to answer the big WHY :)* the OpenShift itself is production ready!

Author of demo: Tero Ahonen, Cybercom Finland5

*

Developers can leverage existing development tools and then access the OpenShift Web, CLI or IDE interfaces to create new application services and push source code via GIT. OpenShift can also accept binary deployments or be fully integrated with a customer’s existing CI/CD environment.

Code

Source 2 Image Walk Through Can configure triggers for automated deployments, builds, and more.

OpenShift automates the Docker image build process with Source-to-Image (S2I). S2I combines source code with a corresponding Builder image from the integrated Docker registry. Builds can also be triggered manually or automatically by setting a Git webhook.

Build

Source 2 Image Walk Through Can configure triggers for automated deployments, builds, and more.

DeployOpenShift automates the deployment of application containers across multiple Node hosts via the Kubernetes scheduler. Users can automatically trigger deployments on application changes and do rollbacks, configure A/B deployments & other custom deployment types.

Source 2 Image Walk Through

Can configure different deployment strategies like A/B, Rolling upgrade, Automated base updates, and more.

Can configure triggers for automated deployments, builds, and more.

Logs and metrics

Why do we need Software Defined Networking?● Containers are designed to come and go. Networking needs automation.● Automation allows extreme elasticity provisioning services● HA models and automated scaling● Locate services where they make the most sense physically

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DMZ

API traffic to control OpenShift

Master1

Master2

Master3

Node

Zone A

Node

Node

Node

Node

Node

Zone B

Node

Node

Node

Node

LB

lb.MyOpenShiftPaaS.com

DMZ

Application traffic via HA-Router with two spares

Master1

Master2

Master3

Node

Zone A

Node

Node

Node

Node

Node

Zone B

Node

Node

Node

Node*.apps.MyOpenShiftPaaS.com

DMZ

Application traffic via HA-Router recovery

Master2

Master3

Node

Zone A

Node

Node

Node

Node

Node

Zone B

Node

Node

Node

Node*.apps.MyOpenShiftPaaS.com

DMZ

Private intranet traffic via another router

Master1

Master2

Master3

Node

Zone A

Node

Node

Node

Node

Zone B

Node

Node

Node

Node

Zone 52

Cluster Ingress via Router

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Machine Outside

of Cluster

ExternalNetwork

Public IP Node IP

Router Pod(on the node)

Node w/ External Access

Public IP Address

(Uses HostNetwork)

ClusterNode

Node IP

Cluster Pod (on the node)

Pod IP Address

SDN Across the Cluster

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VxLAN Overlay

Real Network172.16.1.2 192.168.1.2

10.1.2.x 10.1.3.x

Zone A Zone B

SDN Inside the Node

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iptables NAT

VxLAN

Linux Bridge

lbr0

OVSbr0

Pods Docker Containers

External Network

External Pods

External Systems

eth0

eth0

eth0

Port 4+Port 2tun0

Port 1

Port 3

eth0

eth0

Actualeth0

The technology involvedVirtual Bridge

● Open vSwitch● Linux Bridge

Transport/Tunneling

● VxLAN● VLAN Tagging● UDP Encapsulation● IP Routing

Virtual Interface

● Veth Pair● Tap/Tun

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Integrations for swapping to:

● F5● Nuage● …?

Future:

● Container Network Interface (CNI) for plugins https://github.com/appc/cni

Traffic Inside the Cluster

● Discoverability via Services● Services available as

○ Environment Variables○ Automatic DNS entries

● Simple round-robin-ish load balancing● Leading the community to define flexible access control policy

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● HAProxy Load Balancer

● Built in to the platform

● Supports common web traffic

● F5 BIG IP integration also available

Getting Traffic Into the ClusterOpenShift Router

HTTP

HTTPS TLS SNI

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● Provided by Kubernetes

● Same port on EVERY node forwarded to service

● Can handle non-http traffic

Getting Traffic Into The ClusterService NodePorts

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● Ports on the host where pod is

● Requires custom scheduling

● Can be used to write custom ingress

● This is what the internal router uses

Getting Traffic Into The ClusterHostPorts/HostNetwork

Getting Traffic Out Of The Cluster

● Traffic is NAT’d to the host IP● No current security policy on egress traffic

○ We are working in the community to design egress policies

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OpenShift Router● Stable (configurable) DNS name

○ We often suggest a wildcard DNS to the router○ You can configure DNS by hand route by route

● Application scalability and mobility inside the cluster● Protocols

○ HTTP○ HTTPS (with SNI)○ WebSockets○ TLS with SNI

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Troubleshooting● Try the troubleshooting guide: https://docs.openshift.com/enterprise/3.

1/admin_guide/sdn_troubleshooting.html

● Use plotnetcfg (dnf install plotnetcfg; or clone https://github.com/jbenc/plotnetcfg) to draw a diagram of the networking inside a machine

● Use the same tools as with a physical cluster (except with fewer physical cables to check)

○ ping, tcpdump, wireshark, etc.

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Future directions● We will use the the Container Network Interface (CNI) for plugins

○ https://github.com/appc/cni○ OpenShift SDN will be reimplemented as a CNI plugin○ Why? More feature complete plugin interface○ Hopefully there will be more networking plugins available

● Check out the OpenShift Networking board:○ https://trello.com/b/TV5P9gKe/networking

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OpenStack integrations (future)● LDAP unified user management (Keystone + OSE)● Floating IP and Firewall to help with public traffic● HEAT + ansible installer● Cinder Block Storage as persistent storage *● VLAN aware VLANS will possibly help unifying networks*

Infortaining Youtube flicks to watch:

● OpenShift on OpenStack: https://youtu.be/8Hjk-EImZLk● Case Santander global SDN using Nuage: https://youtu.be/cmr3UZCkL5A● Tenths of excellent tutorials to OpenShift at OpenShift channel: https://www.

youtube.com/channel/UCZKMj3YI0wP-kq4QYpaKdEA27

Conclusion● Don’t be afraid of SDN● It’s the same concepts as a physical network● Virtualizing the components bring many benefits● There are some costs, but most can be worked around, if needed

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