Message boards : Number crunching : Setting up a local Squid to work with LHC@home - Comments and Questions
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computezrmle
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Message 42988 - Posted: 9 Jul 2020, 14:20:14 UTC
Last modified: 9 Jul 2020, 14:23:40 UTC

This is a discussion thread to post comments and questions regarding the Squid Setup HowTo:
https://lhcathome.cern.ch/lhcathome/forum_thread.php?id=5473

Older comments regarding a Squid configuration can be found here:
https://lhcathome.cern.ch/lhcathome/forum_thread.php?id=4611
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Gunde

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Message 42991 - Posted: 9 Jul 2020, 18:38:35 UTC

Thanks computezrmle.
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Henry Nebrensky

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Message 43003 - Posted: 10 Jul 2020, 12:42:46 UTC - in response to Message 42988.  

Nice!

You could add that for "Connecting the BOINC Client" the command-line version is:
boinccmd --set_proxy_settings squid_hostname_or_IP 3128 '' '' '' ''  '' '' ''

(Those are pairs of single-quotes, to specify seven null parameters.)
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computezrmle
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Message 43022 - Posted: 11 Jul 2020, 7:39:51 UTC - in response to Message 43003.  

Thanks for posting.

Most work can be done using optional methods.
This thread is the perfect place to mention them.
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Jim1348

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Message 43051 - Posted: 13 Jul 2020, 18:56:15 UTC - in response to Message 42988.  

As I recall (not very well), if you want to use SQUID only the same machine that you are running BOINC, then in the "squid.conf" file you set:

# Either enter a list of IPs representing your computers that are permitted to use the proxy.
# Each IP on a separate line.
acl crunchers src 127.0.0.1


Is that correct, or should the actual IP address of the machine be used?
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computezrmle
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Message 43053 - Posted: 13 Jul 2020, 20:35:23 UTC - in response to Message 43051.  

It is redundant since a bit below "localhost" is explicitely allowed to use squid:
http_access allow localhost

"localhost" is a built-in keyword that squid resolves to 127.0.0.1
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computezrmle
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Message 43655 - Posted: 19 Nov 2020, 11:58:37 UTC

To all volunteers using the suggested squid.conf from here:
https://lhcathome.cern.ch/lhcathome/forum_thread.php?id=5473

Since David Cameron switched ATLAS Frontier to use Cloudflare's openhtc.io "extra section 2" is now obsolete.


Feel free to remove the following part from your squid.conf or disable all options using a "#" in front of each line (shown here):
#
# Start of extra section 2
# parent cache configuration
#
# ATLAS tasks route frontier requests via predefined WLCG proxy chains including load balancing and fail-over.
# The following lines ensure those proxy chains are respected by a local squid as intended by the CERN ATLAS team.

#acl request_via_atlasfrontier_chain url_regex -i ^http://+atlasfrontier[1-4]?-ai\.cern\.ch:8000/+[^/]+

#cache_peer atlas-db-squid.grid.uio.no parent 3128 0 no-query no-digest weighted-round-robin no-netdb-exchange connect-timeout=7 connect-fail-limit=1
#cache_peer_access atlas-db-squid.grid.uio.no allow request_via_atlasfrontier_chain

#cache_peer dcache.ijs.si parent 3128 0 no-query no-digest weighted-round-robin no-netdb-exchange connect-timeout=7 connect-fail-limit=1
#cache_peer_access dcache.ijs.si allow request_via_atlasfrontier_chain

#cache_peer atlasfrontier-ai.cern.ch parent 8000 0 no-query no-digest no-netdb-exchange connect-fail-limit=1
#cache_peer_access atlasfrontier-ai.cern.ch allow request_via_atlasfrontier_chain

#never_direct allow request_via_atlasfrontier_chain

# End of extra section 2
#



Changes need to be activated running:
squid -k reconfigure
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Toby Broom
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Message 43661 - Posted: 21 Nov 2020, 15:45:40 UTC

You can have 1 server and multiple clients or you need one per PC?

What about the other projects not LHC?
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computezrmle
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Message 43663 - Posted: 21 Nov 2020, 16:30:40 UTC - in response to Message 43661.  

A single Squid instance is enough for the whole LAN.
Frontier experts at Fermilab suggest to run a 2nd instance if you have more than 500 worker slots.
This is thought for fail-over, not because of the load.


Other projects send/receive work via the proxy as soon as it is configured in the BOINC client.
Since most of them use HTTPS Squid simply works as a gateway. It never touches the content of HTTPS traffic.

So far WCG is the only project known to me that requires a special setting.
It fails if it requests files that are already in Squid's local cache.
This can be fixed with a few configuration lines in squid.conf that tell Squid not to cache WCG.
Example (already included in squid.conf):
#
# Start of extra section 1
# Requests that need special handling

# worldcommunitygrid doesn't like it if data is taken from the local cache
acl wcg_nocache dstdomain .worldcommunitygrid.org
cache deny wcg_nocache
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Message boards : Number crunching : Setting up a local Squid to work with LHC@home - Comments and Questions


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