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Prework
In this tutorial we are going to run a simple experiment in GENI, using the Omni command line tool. We are going to take advantage of the Layer 2 links between nodes and run a non-IP experiment.
This is the topology of our experiment:
Before we start with the Omni tutorial, please follow these steps:
- Login to the VM
- Run Firefox
- Open all bookmarks under the Intro to Omni bookmark folder
- Open a terminal window
1. Configure Omni
Omni is a tool that will help you reserve resources in GENI, using your GENI
account. The first step is to load into Omni your account information.
Omni uses a configuration file, and there is a script that will automatically generate the file with
some default options and place it in the default place of ~/.gcf/
. Follow
these steps:
- In the web browser login to
www.pgeni.gpolab.bbn.com
using the information in the paper slip - On the menu on the left, press
Download your cert
- Select the option about downloading as a pem file.
- Press
Ctrl-s
to save this page. Type~/.ssl/geni_cert.pem
- In the terminal type:
omni-configure.py
This should configure your Omni, with your downloaded certificate and create an ssh key pair for logging in to nodes.
When prompted for a passphrase, type the passphrase in your slip. You might be asked for a passphrase multiple times. Note: If you have taken other tutorials, you might have configured omni with other accounts, select to overwrite existing setting if asked
The output should look like:
geni@geni-vm:~$ omni-configure.py {'framework': 'pg', 'configfile': '~/.gcf/omni_config', 'plkey': '~/.ssh/geni_pl_key', 'cert': '~/.ssl/geni_cert', 'verbose': False} INFO:omniconfig:Using configfile: /home/geni/.gcf/omni_config INFO:omniconfig:Using certfile /home/geni/.ssl/geni_cert.pem INFO:omniconfig: CREATING SSH KEYPAIR INFO:omniconfig:Private key stored at: /home/geni/.ssh/geni_key Enter passphrase: INFO:omniconfig:Public key stored at: /home/geni/.ssh/geni_key.pub INFO:omniconfig:Added to /home/geni/.ssh/config this line: 'IdentityFile /home/geni/.ssh/geni_key ' INFO:omniconfig:Wrote omni configuration file at: /home/geni/.gcf/omni_config
OPTIONAL
Open the file ~/.gcf/omni_config
using either vim or emacs. Close to the top of the file you will see two parameters called default_cf
and users
. Your username should be at least listed in the user section. Look for the sections in the file that are named [pg]
and [<username>]
.
In the [<username>]
section, the information need for logging-in to reserved compute resources are provided. It includes your unique user URN and a public key that would be uploaded to the hosts that you reserve.
In the [pg]
section you configure Omni to use your personal information. The cert and the key attribute point to files that we have manually downloaded from pgeni.gpolab.bbn.com. This is equivalent to the Download action of Flack.
Another interesting section to look at is the [aggregate-nicknames]
sections. Flack already knows the URL for all the AMs and present you a list of AMs to choose from using a short, descriptive name. In Omni a user is required to pass the URL for each call to the GENI AM API. In this section the user gets a chance to provide short descriptive names to the URLs that are easier to memorize and use.
2. Clear the passphrase from your cert
When Omni talks to different authorities in GENI, it will need to identify you as a valid GENI user, so it will ask you for your passphrase multiple times. Omni will ask you for the phrase multiple times per command. To save time during the tutorial, we are going to remove the passphrase from your cert and your ssh key. There is a script to clear the passphrases.
- In the terminal run
clear-passphrases.py
Use the passphrase given to you in the paper slip, you might be prompted for a passphrase multiple times make sure you always use the same passphrase.
The output should look like
geni@geni-vm:~$ clear-passphrases.py Do you want to remove the passphrase from your cert (/home/geni/.ssl/geni_cert.pem) [Y,n]?y INFO:clearcert: THIS SCRIPT WILL REPLACE /home/geni/.ssl/geni_cert.pem WITH AN UNENCREPTED CERT. A BACKUP OF THE ORIGINAL CERT WILL BE CREATED INFO:clearcert:The encoded certificate file is backed up at /home/geni/.ssl/geni_cert_enc.pem INFO:clearcert:Removing passphrase from cert... Enter pass phrase for /home/geni/.ssl/geni_cert.pem: writing RSA key INFO:clearcert:Change permissions of /home/geni/.ssl/geni_cert.pem to 0600 Do you want to remove the passphrase from you ssh-key (/home/geni/.ssh/geni_key, key used to login to compute resources) [Y,n]?y INFO:clearcert: THIS SCRIPT WILL REMOVE THE PASSPHRASE FROM YOUR SSH KEY. NO COPY OF THE ORIGINAL PRIVATE KEY WILL BE KEPT Enter PEM pass phrase: Enter passphrase: geni@geni-vm:~$
- Verify that you have the necessary credential and key files
ls ~/.ssh ~/.ssl
The output looks like :geni@geni-vm:~$ ls ~/.ssh ~/.ssl /home/geni/.ssh: config geni_key geni_key.pub /home/geni/.ssl: geni_cert_enc.pem geni_cert.pem
geni_cert.pem Cleartext certificate, i.e. does not require any passphrase geni_cert_enc.pem Encrypted certificate geni_key The private key that you will use to login to the nodes geni_key.pub The corresponding public key that will be uploaded to the nodes
Note: You might see more files than the ones listed above, which are probably backup files from configuring omni, or files from other tutorials.
3. Test Omni setup
In order to test that our configuration is correct, you can issue a getversion
command. For this step we have used PlanetLab's AM, but you can use any
Aggregate Manager(AM).
- In the terminal type:
omni.py getversion -a plc
In GENI each AM can be contacted using a specific URL. In order to make it easier to talk to AMs, Omni uses nicknames; i.e. it maps each URL into an easy to remember nickname. For example the PlanetLab AM listens for requests athttp://www.planet-lab.org:12346
, however you can use the nicknameplc
to refer to that URL. Nicknames are defined in each user's omni_config file.
For the rest of the tutorial we are going to use aggregate nicknames.
4. Create an experiment using Omni
In this step we are going to setup a sample GENI experiment, in order to get familiarized with most of the Omni commands.
4a. Create and renew a slice
The first thing to do when preparing to run a GENI experiment is to create a slice.
- To create a slice type, use the
<slicename>
given in your paper slip:omni.py createslice <slicename>
- To verify that your slice has been created and in general to keep track of
your slices, use the list_my_slices command. use the <username> given in your
paper slip. Type:
omni.py list_my_slices <username>
- Renew your slice. To extend the lifetime of your slice type:
omni.py renewslice <slicename> 20121025
4b. Reserve resources, a.k.a create a sliver
The next step in a GENI experiment is to actually reserve resources. For this experiment we are going to use the Aggregate manager of ProtoGENI in Utah.
- In Omni in order to see what each AM offers you can use the
listresources
command. Type:omni.py listresources -a pg-utah -o
The-o
option will save the output to a file. The filename is chosen by Omni and printed as part of the output. The output will look like :geni@geni-vm:~$ omni.py listresources -a pg-utah -o INFO:omni:Loading config file /home/geni/.gcf/omni_config INFO:omni:Using control framework pg INFO:omni:Saving output to a file. INFO:omni:Substituting AM nickname pg-utah with URL https://www.emulab.net/protogeni/xmlrpc/am, URN unspecified_AM_URN INFO:omni:Listed resources on 1 out of 1 possible aggregates. INFO:omni:Writing to 'rspec-www-emulab-net-protogeni.xml' INFO:omni: ------------------------------------------------------------ INFO:omni: Completed listresources: Options as run: aggregate: pg-utah framework: pg native: True output: True Args: listresources Result Summary: Retrieved resources from 1 aggregates. Wrote rspecs from 1 aggregates to 1 files Saved listresources RSpec at 'unspecified_AM_URN' to file rspec-www-emulab-net-protogeni.xml; . INFO:omni: ============================================================
Open the file that Omni saved and just take a look to see how an advertisement RSpec looks like. In order to see only available resources resources typeomni.py listresources -a pg-utah --available -o
- To be able to reserve resources you will need to craft a request rspec.
For this example we have created the rspecs for you, use the rspec URL given
in your paper slip. Type :
omni.py createsliver -a pg-utah <slicename> <rspec_url>
- Look at your reserved resources. Type:
omni.py listresources -a pg-utah <slicename>
- Check the status of your resources. Type:
omni.py sliverstatus -a pg-utah <slicename>
Thesliverstatus
command reports the status of your overall GENI slice. When the status is ready we are ready to continue to the next step.
5. Run your experiment
Now that resources are ready we can start running our experiment. We will first start by logging in to our reserved nodes.
5a. Logging Into the nodes -- Omni Scripting
Depending on the Aggregate the login information are either part of the
sliverstatus
call, or as part of the manifest rspec, i.e. returned from the
listresources
call. Omni comes with a script that makes it easy to gather all
this information.
- In the terminal run:
readyToLogin.py -a pg-utah <slicename>
The script will return the actual command that you would need to use for logging in. - Login to both nodes by copy-paste the commands from the output of the script.
5b. Send IP traffic
The first simple experiment that we will run is to verify the IP connectivity between our hosts.
- Check the interfaces of your nodes. In the terminal type:
/sbin/ifconfig
You should see at least two interfaces:- The control interface. This is the interface from where you 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 control interface has a publicly routable IP.
- 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.
- Note the name and the MAC address of the control and of the data interface for each node.
- From the client ping the server. From the xterm that is logged in to the
client type :
ping server -c 5
Note: You can use the name that is assigned to the host to directly ping the host, you can also ping using the IP of the data interface of the node. An example output should look like :[[inki@r2 ~]$ ping server -c 5 PING 10.10.2.1 (10.10.2.1) 56(84) bytes of data. 64 bytes from 10.10.2.1: icmp_seq=1 ttl=64 time=1.95 ms 64 bytes from 10.10.2.1: icmp_seq=2 ttl=64 time=2.27 ms 64 bytes from 10.10.2.1: icmp_seq=3 ttl=64 time=2.04 ms 64 bytes from 10.10.2.1: icmp_seq=4 ttl=64 time=1.95 ms 64 bytes from 10.10.2.1: icmp_seq=5 ttl=64 time=1.72 ms --- 10.10.2.1 ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 4005ms rtt min/avg/max/mdev = 1.728/1.992/2.278/0.179 ms
5c. Send non-IP traffic
GENI provides the capability of running non-IP experiments, since you can connect your hosts at Layer 2. For the purpose of this tutorial we have installed in all the hosts a very simple Layer 2 ping program that sends packets using a custom ethernet type.
- Disable the IP in your nodes. First of all we are going to completely
disable IP on our nodes. In each of the terminals type:
sudo /sbin/ifconfig <data i/f name> 0.0.0.0
Note: Be extra careful to bring down the IP on the data interface, bringing down the IP on the control interface means that you will lose connectivity to your host. - Try again to ping from the client to the server. In the xterm of the
client type:
ping server -c 5
This time the ping should timeout. - Start the Layer 2 ping server: In the server xterm, type:
sudo /usr/local/bin/pingPlusListener
- From the client try to ping the server at layer 2. You will need the mac
address of the data interface of the server and the name of the data interface
of the client. In the xterm of the client, type:
sudo /usr/local/bin/pingPlus <server data mac addr> <client data i/f name> 12345
The result should look like :
[uncusr20@client ~]$ sudo /usr/local/bin/pingPlus 02:00:9B:48:3E:20 mv1.1 12345 RQ:'5582+2067' to 2:0:9b:48:3e:20. RQ:5582+2067 from 2:0:3e:15:6c:ab.
Congratulations you have run a Layer 2 experiment in GENI!
6. Cleanup resources
Although all your reservations, have expiration times, you should always release your resources once you have completed your experiment to make them available to other experimenters.
- In the terminal, where you have been running your omni commands do:
omni.py deletesliver -a pg-ky <slicename>
Congratulations, you have finished the tutorial! Now you are ready to design and run your own experiments. Don't hesitate to email us with any questions you might have.
7. Fill out the tutorial survey
We love to hear what you think so that we can improve the tutorials in the future. Please complete the online survey and get a temporary GENI tatoo!
8. Get Your Own Account
The accounts, that you used in the above steps will be deactivated after the tutorial. If you do not already have an account at GPO's ProtoGENI cluster, you should get your own account so that you can further experiment with GENI. If you are not a professor and you want to setup your account today, please follow these steps:
- In your browser go the www.pgeni.gpolab.bbn.com tab and click
Logout
- Press in the .... button.
- Fill out the information that are requested and for Project name use ..... Note: Make sure you use a valid email address and preferably the email address of your institution. You will need to verify your email address before your account can be approved.