LHC@home

A previous version of this HowTo can be found here:
https://lhcathome.cern.ch/lhcathome/forum_thread.php?id=5342&postid=41861

New comments and questions should be posted here:
https://lhcathome.cern.ch/lhcathome/forum_thread.php?id=5595



The settings described in this HowTo should be used by all volunteers running a local CVMFS client in connection with ATLAS/Theory native.

Exception:
Sites/Volunteers who have individual arrangements with CERN should follow those, e.g. tier-x-sites or Agile Boincers.



The basic CVMFS packages are widely used within CERN and other large research facilities around the world.
Hence, they configure HTTP requests to be made to CVMFS stratum 1 servers and they always expect a site proxy to be used.

Volunteers from LHC@home should not use the stratum 1 servers but instead the openhtc.io CDN (Content Delivery Network) provided by Cloudflare.
To enable this just add "CVMFS_USE_CDN=yes" to /etc/cvmfs/default.local and run "cvmfs_config reload" as root.


A complete /etc/cvmfs/default.local should have at least the following settings:

# Must be set: the repositories required for ATLAS/Theory
# If "CVMFS_DEFAULT_DOMAIN" is set to "cern.ch" like in /etc/cvmfs/default.d/50-cern.conf
# simple names will expand to FQRNs,
# e.g. atlas -> atlas.cern.ch
CVMFS_REPOSITORIES="atlas,atlas-condb,grid,cernvm-prod,sft,alice"

# Must be set: to ensure openhtc.io will be used
CVMFS_USE_CDN=yes


# If a local proxy <my_proxy> is available that listens at port <proxy_port>.
# Replace <my_proxy> with either:
# - the computer name of your local proxy; requires a well configured local name resolution
# - the FQDN of your local proxy; requires a well configured local name resolution
# - the IP of your local proxy
# Replace <proxy_port> with your proxy's TCP port; Squid's default would be 3128
# Pattern: CVMFS_HTTP_PROXY="http://<my_proxy>:<proxy_port>;DIRECT"
# Example: 
CVMFS_HTTP_PROXY="http://squid:3128;DIRECT"

# Only recommended for clusters <5 worker nodes:
# uncomment the next line if no local proxy is available.
# CVMFS_HTTP_PROXY="auto;DIRECT"



# further options
CVMFS_KCACHE_TIMEOUT=2
CVMFS_MAX_RETRIES=3

# EOF

CVMFS_SEND_INFO_HEADER doesn't need to be set in /etc/cvmfs/default.local any more and may be removed.





Useful Tests

To be run as root.


cvmfs_config showconfig
Prints a long list of all configuration settings. Shows from which config file each option is taken.


cvmfs_config probe
Should output a line like "Probing /cvmfs/atlas.cern.ch... OK" for each configured repository.
If this command reports failures the reason must be fixed. Otherwise native tasks will fail.


cvmfs_config stat
Output should look like this if a local proxy is in use:

VERSION PID UPTIME(M) MEM(K) REVISION EXPIRES(M) NOCATALOGS CACHEUSE(K) CACHEMAX(K) NOFDUSE NOFDMAX NOIOERR NOOPEN HITRATE(%) RX(K) SPEED(K/S) HOST PROXY ONLINE
2.7.5.0 18766 43031 115488 78163 0 58 7013424 9961473 4200 65024 1 6912614 99.9275 1317812 1320 http://s1cern-cvmfs.openhtc.io/cvmfs/atlas.cern.ch http://192.168.77.14:3128 1

The pattern s1xxxx-cvmfs.openhtc.io shows that a CDN server is in use.
The IP 192.168.77.14 shows the HTTP proxy currently in use. It should be checked if this is the IP of the local proxy.
After a while (could be a day) the CVMFS hitrate should be checked. Here 99.9275 %.
If the hitrate of heavily used repositories like atlas.cern.ch never goes above 95 % this should be added to /etc/cvmfs/default.local:

# Default disk cache size: 4000 MB
# might be enlarged up to 10000 MB
CVMFS_QUOTA_LIMIT=6000

Output from "cvmfs_config stat" if no local proxy is used:

VERSION PID UPTIME(M) MEM(K) REVISION EXPIRES(M) NOCATALOGS CACHEUSE(K) CACHEMAX(K) NOFDUSE NOFDMAX NOIOERR NOOPEN HITRATE(%) RX(K) SPEED(K/S) HOST PROXY ONLINE
2.7.5.0 18766 43031 115488 78163 0 58 7013424 9961473 4200 65024 1 6912614 99.9275 1317812 1320 http://s1cern-cvmfs.openhtc.io/cvmfs/atlas.cern.ch DIRECT 1

Changes to the configuration must be finished running "cvmfs_config reload" as root.