Kronosnet

AN!Wiki :: Kronosnet

What is Kronosnet

First, the homepage.

• Home page

Kronosnet is a new network topology designed by Red Hat to provide highly adaptable, redundant and secure networking over both high and low-speed links.

In a sense, kronosnet is similar to a VPN in that connections between nodes are on a common subnet. Unlike traditional VPNs though, kronosnet can be configured to use up to eight physical interfaces. While operating, the kronosnet daemon, kronosnetd, will keep track of the latency between links. This allows for the fastest link to always be chosen. This approach means that dead links need no special handling as they will have an infinite latency and thus never be used. When the link finally recovers, it will "just work", as it's latency will suddenly be reasonable again.

This means that, so long as at least one link is up, communication to the host will work, regardless of what happens to the underlying network links!

Further, if no direct link exists between two nodes, but communication is possible through a third node, then messages will route properly!

Consider the following:

  ____________                              ____________
 | Node A     |                            |     Node B |
 |    _______ |                            | _______    |
 |   | Link1 ==----------------------------== Link1 |   |
 |   |______| |                            | |______|   |
 |    _______ |                            | _______    |
 |   | Link2 ==-\                        /-== Link2 |   |
 |   |______| | |                        | | |______|   |
 |____________| |                        | |____________|
                |                        |
                |  ____________________  |
                | |       Node C       | |
                | | _______    _______ | |
                \-== Link1 |  | Link2 ==-/
                  | |______|  |______| |
                  |____________________|

If the direct link between Node A and Node B is lost, kronosnet will still be able to route traffic via Node C! All of this will the minimal of configurations. Once finished, kronosnet communication will be also encrypted.

Think of it like a VPN on steroids.

Q. Fabio mentioned something about "costs" of links, to help avoid expensive bandwidth. Get clarification.

Install

At this time, installation is a very manual affair involving:

1. Cloning a git repository
2. Switching to a known-good branch
3. Compiling and installing
4. Setting up pam.d.
5. Adding a user and group
6. Starting the daemon
7. Configuring the interfaces
8. Save the config to a file

For The Impatient

This is a pretty dirty little chain of bash commands that will do everything up to starting the daemon. These aren't well documented as most of this will be taken care of in the eventual RPM package.

At the time of this writing, the checkout with hash c2a42967d7dbba7c06a6124760c9881337499986 is known to work. The code changes daily, and sometimes hourly. I'll update this page as quasi-stable checkouts are found to be stable.

# Meet dependancies
cd ~
yum -y groupinstall "Development Tools"
yum -y install pam-devel

# Setup the user and group.
groupadd -r kronosnetadm 
groupmems -g kronosnetadm -a root
useradd kronosnet -b /etc -M -r -s /bin/bash -G kronosnetadm
passwd kronosnet

# Create a pam.d directory entry. We cheat by linking to an existing entry.
ln -s /etc/pam.d/system-auth /etc/pam.d/kronosnet

# Now clone, checkout, compile, make, install and run the daemon
git clone git://github.com/fabbione/kronosnet
cd ~/kronosnet
git checkout c2a42967d7dbba7c06a6124760c9881337499986
./autogen.sh
./configure
make
make install
kronosnetd

# Finally, login! Note that by default, sessions will close after 60
# seconds of inactivity
telnet localhost 50000

Create a user and group for kronosnet to run as.

### This doesn't add the user to the group for some reason...
groupmems -g kronosnetadm -a kronosnet

Set a password for the new kronosnet.

Configure

The configuration is done in the kronosnet command line which you can access with telnet. Once your setup is how you like it, you can tell kronosnet to save it to a file for loading when the daemon (re)starts later.

Overview

At this time, you must know and and define all nodes in the network, all ethernet interfaces they have and what their IP addresses are. Plans are to make this more adaptable over time, but for now this is an admitted draw-back. For this reason, it is strongly advised that all of the interfaces you plan to use for kronosnet have static IP addresses. Either IPv4 or IPv6 will work fine. In this paper, IPv4 will be used for familiarity's sake.

Nodes

To have a common verbiage, lets define the following two nodes, each with three statically assigned network interfaces.

• an-node03
  • eth0 - 192.168.1.73
  • eth1 - 192.168.2.73
  • eth2 - 192.168.3.73
  • knet0 - 192.168.4.73

• an-node04
  • eth0 - 192.168.1.74
  • eth1 - 192.168.2.74
  • eth2 - 192.168.3.74
  • knet0 - 192.168.4.74

The kronosnet Command Line

an-node03

configure
 interface knet0 0
  baseport 50000
  mtu 9000
  ip 192.168.4.73 24
  peer an-node04 1
   link 192.168.1.74
    exit
   link 192.168.2.74
    exit
   link 192.168.3.74
    exit
   exit
  start
  exit
 exit
exit

an-node04

configure
 interface knet0 1
  baseport 50000
  mtu 9000
  ip 192.168.4.74 24
  peer an-node03 0
   link 192.168.1.73
    exit
   link 192.168.2.73
    exit
   link 192.168.3.73
    exit
   exit
  start
  exit
 exit
exit

Create The pam.d Access File

ln -s /etc/pam.d/system-auth /etc/pam.d/kronosnet
ls -lah /etc/pam.d/kronosnet

lrwxrwxrwx 1 root root 22 Dec 13 15:27 /etc/pam.d/kronosnet -> /etc/pam.d/system-auth

Run the Daemon

There is currently no init.d script for kronosnetd, so it will need to be started manually.

Must run os 'root'.

kronosnetd

There is no output from that command, and it will daemonized and return you to the shell. You can check that it is running with ps.

Network Setup

In this tutorial, we'll use four nodes, each with three network cards.

• an-node03
• an-node04
• an-node05
• an-node06

To log in for the first time, use telnet to connect to the localhost on TCP port 50000.

telnet localhost 50000

Trying ::1...
Connected to localhost.
Escape character is '^]'.
Welcome to kronosnetd 0.1 (built Nov 28 2010 13:32:00)

login:

At this point, you can login using the kronostnet user name and justatest password. Once logged in successfully, you should see the knet prompt.

login:kronosnet
Password: 

Welcome kronosnet (::1) on vty(0)

knet#

To quit at any time, simply enter the telnet escape code. This is usually ^] (<ctrl> + ])

Notes

Stuff here is random

• 8 links per node
• 2^16 (64,000) nodes
• git checkout c2a42967d7dbba7c06a6124760c9881337499986
• conf -> write will save the config and load it when the daemon starts
  • /etc/kronosnet/kronosnet.conf
• it will be possible to define it manually, for testing is set to 60 seconds, default will be 600
• Seq # does not have to be sequential, just a number between 0 <= x <= 255
• if interface foo has value 0, no peer can have 0

 

Any questions, feedback, advice, complaints or meanderings are welcome.
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