Setup Torrent

Setting up a VOBox for torrent use

 

This wiki page aims to explain the steps that should be taken on a VOBox in order to use bit torrent.

 

  • AliEn

Please make sure that the latest version of AliEn is installed on the VOBox, some fixes or improvements may be needed for a smooth running. Also remember stopping the services before the update, and starting them again afterwards.

 

It is very important that (unless the homedir has less than ~100GB) the new installation goes to the homedir of the alicesgm user, not in the shared SW directory anymore. The homedir size should be also at least 200-250 GB for packages installation. If this is not possible, an alternative could be linking the new packages directory to the old one.

 

  • Networking (Firewall) prerequisites

Below is the minimal set of ports that need to be allowed in the firewall for the torrent method to work

- Allow outgoing access from the WNs to alitorrent.cern.ch: TCP/8088,8092 (tracker and seeder).

- Don't allow incoming connection requests from the world to the WNs, but don't be surprised if they do talk to other outside nodes (users that have the package...).

- Allow WN-to-WN connections on at least:
TCP,UDP/6881:6999 – aria2c default listening port range, TCP for BT communication, UDP for DHT
UDP,IGMP → 224.0.0.0/4 – local peer discovery.

 

  • Other considerations

You can install your own aria2c client on the system to avoid downloading it for bootstrap.

In the default configuration file ($HOME/.aria2/aria2.conf) you can tune it more to your liking, for example:
- Enabling JSON/XML-RPC for local activity monitoring
- Custom listening ports
- HTTP proxies

 

  • LDAP

When the site is ready for the change the last step is changing the LDAP configuration. The change is done by the CERN team in sync with the site administrators, below is a template of what has to be changed to enable this software distribution model:

 

ou=[Site name], ou=Services, ou=CE, name=[CE name]
installMethod="Torrent"

ldap_ce

 

ou=[Site name], ou=Services, ou=PackMan, name=[PackMan instance name]
installDir="$ALIEN_ROOT/packages/"

By convention the PackMan name would end in "_torrent" like "LCG_torrent". Also make sure that "forbidWnInstall" is not set.

 

ldap_packman

 

ou=[Site name], ou=Config, host=[vobox fqdn]
cachedir="$ALIEN_ROOT/tmp/alien_cache"
tmpdir="$ALIEN_ROOT/tmp/alien_tmp"

logdir="$ALIEN_ROOT/alien-logs"

 

ldap_host