PlanetLab

What is PlanetLab? A group of computers available as a testbed for computer networking and distributed systems research. – computers located in more than 40 countries – allows researchers to run their experiments in a real world scenario on nodes which are thousands of miles apart Initiated in 2002 by Dr. Larry L. Peterson – As of Mar 2014 is composed of 1184 nodes at 577 sites worldwide

PlanetLab

PlanetLab is… Large collection of machines spread around the world for distributed systems research Can deploy and run code in Seoul, San Francisco, Rio de Janeiro, Moscow, Mumbai, … Most major Universities now host sites

The value proposition Institutions join, provide nodes – IA32 architecture servers – Hosted outside the firewall – Provide power, cooling, & bandwidth In exchange, researchers get to use a small “slice” of many machines worldwide.

PlanetLab is not… A distributed supercomputer A simulation platform An Internet emulator An arena for repeatable experiments Completely representative of the current Internet

PlanetLab is… An opportunity to qualitatively validate distributed systems research in a real deployment environment An opportunity to gain valuable experience about what works and what doesn’t in the wide area at scale

What is it good for? PlanetLab addresses the related problems of: – Deploying widely-distributed services – Evaluating competing approaches in a realistic setting – Evolving the network architecture to better support such services

How to use PlanetLab Don’t expect: – Repeatable experiments, other than very long-running studies – Large numbers of nodes (approx 1000) – Lots of CPU (machines are loaded!) – High availability machines reboot without warning Do expect: – The unexpected! – Real experience running a service – Real users (if you want them) – Lots of interesting challenges – To find out if your idea really works

Introductıon to PlanetLab a)Principal Investigator. PI is the controller of PlanetLab nodes at a particular site and is responsible for everything being done by users of the site. He gives approval of new user accounts, creates slices, etc. b)Technical contact. He is responsible for installing PlanetLab operating system on new nodes, monitoring of nodes and day to day maintenance if required. c)User. Actual user who conducts experiment on PlanetLab. d)PLC. It is an abbreviation for PlanetLab Central. PLC is the main controller of PlanetLab. They provide basic interface for controlling and managing slices and nodes. e)Site. A physical location where nodes have been kept e.g. University of Nevada, Reno f)Node. Actual computers provided by the participating universities / organizations. Minimum of two nodes have to be provided by each participating university / organization. Linux operating system runs on these computers. g)Slice. It is a network wide resource container. A maximum of 10 slices can be created by Principal Investigator of a university and only two slices by Principal Investigator of an organization. Any number of Nodes can be added to a slice. Slices can only be created by Principal Investigator but users can add nodes to them. h)Sliver. It is actual allocated resources on a node. Slivers are implemented using Linux

How to use PlanetLab Create an account on planet-lab.org Select: “university of Nevada, Reno” as Site

Registering planet-lab.org After registering, your registration request goes to site_admin Site_admin should approve your request After site_admin approves your request, your account is created.

Using nodes There are two nodes (servers) in UNR that are allocated for planet-lab.org These nodes are under administration of UNR PI (site_admin) To be able to use these nodes for your experiments – You have to be assigned to a slice by PI (site_admin) – After you are assigned to a slice, you can add as many nodes as you wish to your slice The nodes that you want to add into your slice don’t have to be just UNR nodes You can add nodes from different universities, organizations, etc.

Connecting to your slice To be able to connect to a slice you need to use SSH – Secure Shell (SSH) is a cryptographic network protocol for secure data communication You can either use Linux (preferred) to connect to your slice or you can connect to you slice using Windows

Connecting from Windows Following software can be used to access PlanetLab nodes using Microsoft OS. a)Putty. It is used for making connection with remote PlanetLab node. b)Putty gen. It is used for generating public and private key pair. c)PSCP. It is used for transferring files to remote nodes. All these software are executable programs therefore there is no need to install them. They can be downloaded for free from the following address :

Key generation In order to communicate with PlanetLab nodes you need public/private key pair. Putty generator will be used for creating public and private key pair. In putty generator GUI, select SSH-2 & 1024 as number of digits in key and then press generate key.

Generating Private Key Click ‘Save private key’ and copy public key form putty generator window and save it in a text file.

Key Upload Go to PlanetLab’s web site and open your account. Select ‘My Account’ sub menu and click on ‘Key’. It will display browse and upload option. Upload the text file containing the public key.

Key Upload

Adding Nodes to Slice Open your account and go to ‘My Slices’. Click on your slice name. It will display list of nodes which are part of slice. Select and click in front of nodes which you want to add to your slice and click on ‘add selected’. – It will only be possible if Principal Investigator has already created slice for you.

Communicating with your slice Open putty by double clicking on it. Select session and write down IP address of the remote node. Assign this session a name in ‘Saved Sessions’ and click ‘Save’. Click on ‘Auth’ under ‘SSH’ category given on left plane. Browse and point to the place where file containing private key was saved. Click on ‘Open’. If everything goes fine, then a command comm window with active prompt & name of slice will open. You can type ‘pwd’ to see path of your current directory and ‘ls’ to list files’ names in this directory. At that moment, there will be no programs installed on the remote node.

Connecting from Linux Create an SSH key – Before you can access any PlanetLab nodes, including those at your own site, you must create an SSH key pair for authentication purposes. – Remote access to PlanetLab nodes is restricted to SSH login using RSA authentication. RSA authentication is based on public-key cryptography. Encryption and decryption are performed with separate keys It is not possible to derive the decryption key from the encryption key To generate an SSH key pair, use the ssh-keygen program on a secure UNIX system: ssh-keygen -t rsa -f ~/.ssh/id_rsa

Connecting from Linux Upload the public key under the directory of /.ssh (this file is in hidden format) to your account in planet-lab.org Assign nodes to your slice using planet-lab.org interface. You can now connect to your slice by typing: ssh –l name_of_slice –i ~/.ssh/id_rsa planetlab1.unr.edu IMPORTANT !! After you upload your public key to your account, you have to wait about an hour for it to be active. If you are using putty, after connecting, it may ask “Login as:” and you should enter your slice name here.

ssh-agent In Unix, ssh-agent is a background program that handles passwords for SSH private keys. The ssh-add command prompts the user for a private key password and adds it to the list maintained by ssh-agent Once you add a password to ssh-agent, you will not be prompted for it when using SSH or scp to connect to hosts with your public key. You will be able to connect to a node by: ssh –l name_of_slice planetlab1.unr.edu ssh –l name_of_slice –i ~/.ssh/id_rsa planetlab1.unr.edu Instead of typing:

ssh-agent Note: The public part of the key loaded into the agent must be put on the target system in ~/.ssh/authorized_keys; To use ssh-agent and ssh-add, follow the steps below: 1.At the Unix prompt, enter: eval `ssh-agent` 2.Note: Make sure you use the backquote ( ` ), rather than the single quote ( ' ). 2.Enter the command: ssh-add 3.Enter your private key password. 4.When you log out, enter the command: kill $SSH_AGENT_PID 5.To run this command automatically when you log out, place it in your.logout file (if you are using csh or tcsh) or your.bash_logout file (if you are using bash).

Uploading files to Nodes (with putty) PSCP will be used to copy program to remote node. PSCP is command line tool. Open it in command prompt by typing PSCP (inside the putty directory). – Syntax for copying file to remote node is as under : C:\>…\putty>pscp -scp c:\file name plab:/home/canterbury_slice1 – First part ‘-scp ’ is forcing PSCP to use scp protocol – second part ‘c:\file name’ is location and name of the file to be copied – third part ‘plab’ is name of session saved in Putty – last part ‘/home/canterbury_slice1’ is location on remote node where the file has to be saved. This location can be found by typing ‘pwd’ in command comm of remote node.

Uploading files to Nodes (by Linux) The most straightforward way of deploying your application to a single node is with scp: – Or, using ssh-agent – If your slice were named unr_test1, following command would copy the local directory test1 to your home directory on planetlab1.unr.edu. scp -i ~/.ssh/id_rsa –r my_file scp my_file scp my_file

Downloading files from Nodes (by Linux) Login to the node that contains the file which you want to download, enter following scp command: scp my_file directory_place scp my_file /root/projects/planetlab/downloads

How to manage multiple nodes? There are applications such as CoDeploy, Plush, pssh, Nixes, pShell, etc. – Many of them retired – Not up to date – Confusing Writing script strongly recommended! – Python scripts