''' This is a working draft. ''' = [http://groups.geni.net/geni/wiki/GENIExperimenter/Tutorials/GettingStarted_PartI/Procedure Lab Zero: A First Experiment Using GENI] = {{{ #!html
Image Map
}}} == 4. Configure and Initialize == Now that you have reserved your resources, you are ready to run your first GENI experiment. === 4.1 Login to nodes === {{{ #!html
  1. To login to a VM, again click the i in the circle.
  2. Now, click on the ssh link. If you have installed FireSSH a new tab will open up.
  3. In the window that will pop up :
    • in the password field type in your passphrase
    • for the private key, browse to the file that has your private key
    • Press OK
  4. Repeat the previous step for the second VM.
Tip To ssh from the command line, do the following (substituting the values shown on the screen):
ssh USERNAME@HOSTNAME -p PORT
Login information for a VM
Figure 4-1 Login to a VM.
}}} == 5. Execute Experiment == === 5.1 Send IP traffic === The first simple experiment that we will run is to verify the IP connectivity between our hosts. a. Check the interfaces of your nodes. In the terminal type: {{{ sudo ifconfig }}} You should see at least two interfaces: * The '''control interface'''. This is the interface you use to access the node, e.g. ssh into your host. The control interface is mainly used for control traffic, i.e. traffic for controlling the node and the experiment. * The '''data interface'''. This is the interface that is used for sending experimental traffic. This is the interface that connects to the other hosts of your experiment through GENI. The links between these interfaces are the ones that allow you to run non-IP experiments. '''The data interface is the one that has an IP address and mask that match what you configured before you reserved your resources.''' b. Fill in the worksheet, noting the name and IP address of the control and of the data interfaces for each node. {{{ #!html
Tip The command prompt on each node says "client" or "server" respectively.
}}} c. From the client, `ping` the server '''data plane interface'''. From the terminal window that is logged in to the client type : {{{ ping -c 5 }}} For example: {{{ ping 10.17.1.2 -c 5 }}} d. Now, `ping` the server '''control plane interface'''. From the terminal window that is logged in to the client type : {{{ ping -c 5 }}} For example: {{{ ping 172.17.1.9 -c 5 }}} === 5.2 Install and use `iperf` === a. Install the `iperf` software on both nodes, by running the following command: {{{ sudo yum install iperf }}} {{{ #!html
InstaGENI InstaGENI nodes have `iperf` pre-installed in `/usr/local/etc/emulab/emulab-iperf`.
}}} b. Start an `iperf` server on the server node: {{{ /usr/bin/iperf -s }}} c. Run an `iperf` client via the data plane: {{{ /usr/bin/iperf -c }}} For example: {{{ /usr/bin/iperf -c 10.1.1.2 }}} ''What is the bandwidth of this link?'' ''Why?'' d. Run an `iperf` client via the control plane: {{{ /usr/bin/iperf -c }}} For example: {{{ /usr/bin/iperf -c 172.17.2.2 }}} ''What is the bandwidth of this link?'' ''Why?'' === 5.3 Take down the data interface === a. ExoGENI nodes run a service called "neuca" that managed network interfaces on the node. To manually adjust the IP address, we must first disable neuca on both nodes. {{{ sudo service neuca stop }}} {{{ #!html
ExoGENI The ExoGENI "neuca" service controls a variety of network configuration details.
}}} b. On the server node, bring down the '''data plane interface''' (being careful to disable the data interface NOT the control interface): {{{ sudo /sbin/ifconfig down }}} c. From the client node, try to ping the server '''data plane interface''': {{{ ping -c 5 }}} ''This time the ping should indicate that the destination is unreachable.'' ''Why?'' {{{ #!html
Warning Be extra careful to disable the IP on the data interface, bringing down the IP on the control interface means that you will lose connectivity to your host.
}}} === 5.4 Bring down the control interface === a. From the server node, bring down the '''control plane interface''' and try to ping it from the client node: {{{ sudo /sbin/ifconfig down }}} ''Your ssh session should immediately hang.''' ''Why?'' b. From the client node, try to ping the server '''control plane interface''': {{{ ping -c 5 }}} ''What happens? Why?'' {{{ #!html
Tip Unfortunately, in order to recover from a situation like this where you've lost the ability to login to your nodes, the only way to recover is to delete your resources and start again.
}}} == 6. Analyze Experiment == Now is when you would ordinarily analyze the results of your experiment. === 6.1 Logout of your nodes === * Then type `exit` in your open terminal. Congratulations you have run an experiment in GENI! ---- = [wiki:GENIExperimenter/Tutorials/GettingStarted_PartI/Procedure Introduction] = = [wiki:GENIExperimenter/Tutorials/GettingStarted_PartI/Procedure/Finish Next: Finish] =