Hi Santanu
Thank you for spotting that, it should indeed be a capital F. I
thought I had copied and pasted the commands directly but maybe my
mail client decided to do some formatting. That should fix most of
the problems as the Frontier server/squid should be accessible to all.
If we were to make this change, it would not make RAL a single point
of failure. In order for their to be a failure both your own squid
and RAL would have to fail If RAL fails your own squid should be set
up to access PIC. The current situation means that if you and your
back squid fail, things will break. (If both RAL and PIC are down
then you will also fail under both systems but multiple T1 failures
should hopefully be rare!)
Alastair
So the new instructions are:
Log into a WN
> wget http://frontier.cern.ch/dist/fnget.py
> export http_proxy=http://lcgft-atlas.gridpp.rl.ac.uk:3128
> python fnget.py --url=http://lcgft-atlas.gridpp.rl.ac.uk:3128/
frontierATLAS/Frontier --sql="SELECT TABLE_NAME FROM ALL_TABLES"
This should provide a big list of table names and not a python error!
On 16 Jun 2010, at 11:51, Santanu Das wrote:
> Hi Alastair and all,
>
> I think there is typo in the URL, it should be "http://lcgft-
> atlas.gridpp.rl.ac.uk:3128/frontierATLAS/Frontier" *not* "frontier"
> with small f. Now it works for with or without a http_proxy setting.
>
> [root@farm002 tmp]# unset http_proxy [root@farm002 tmp]# python
> fnget.py --url=http://lcgft-atlas.gridpp.rl.ac.uk:3128/
> frontierATLAS/Frontier --sql="SELECT count(*) FROM ALL_TABLES"
> Using Frontier URL: http://lcgft-atlas.gridpp.rl.ac.uk:3128/
> frontierATLAS/Frontier Query: SELECT count(*) FROM ALL_TABLES
> Decode results: True Refresh cache: False Frontier Request: http://
> lcgft-atlas.gridpp.rl.ac.uk:3128/frontierATLAS/Frontier?
> type=frontier_request:
> 1:DEFAULT&encoding=BLOBzip&p1=eNoLdvVxdQ5RSM4vzSvR0NJUcAvy91Vw9PGJD3F0
> 8nENBgCQ9wjs Query started: 06/16/10 11:44:15 BST Query ended:
> 06/16/10 11:44:16 BST Query time: 1.34605288506 [seconds] Query
> result: <?xml version="1.0" encoding="US-ASCII"?> <!DOCTYPE
> frontier SYSTEM "http://frontier.fnal.gov/frontier.dtd"> <frontier
> version="3.22" xmlversion="1.0"> <transaction payloads="1">
> <payload type="frontier_request" version="1" encoding="BLOBzip">
> <data>eJxjY2Bg4HD2D/UL0dDSZANy2PxCfZ1cg9hBbBYLC2NjdgBW1ATW</data>
> <quality error="0" md5="3c31cc5665b2636e8feb209fafa558f6"
> records="1" full_size="35"/> </payload> </transaction> </frontier>
> Fields: COUNT(*) NUMBER Records: 8833 Cheers,
> Santanu
>
>
>> Hi
>>
>> The current state of the ATLAS frontier service is not ideal. The
>> SAM tests:
>> https://lcg-sam.cern.ch:8443/sam/sam.py?CE_atlas_disp_tests=CE-
>> ATLAS-sft-Frontier-
>> Squid&order=SiteName&funct=ShowSensorTests&disp_status=na&disp_status
>> =ok&disp_status=info&disp_status=note&disp_status=warn&disp_status=er
>> ror&disp_status=crit&disp_status=maint
>> show several production sites getting a warning. This warning is
>> normally caused by the backup squid not being configured correctly.
>>
>> To remind people: WNs should connect to the local squid (normally
>> at the site) which connects to the Frontier server at RAL. If the
>> local squid is down then the WN will try and connect to a backup
>> squid which is meant to be at a nearby site which will then try
>> and connect to the Frontier server. There is a similar backup
>> process should the Frontier server at RAL fail then all the squids
>> will try and connect to the frontier server at PIC.
>>
>> To ease this problem it has been suggested that the default backup
>> for Tier 2 sites is the squid at RAL (The Tier 1 not the Tier
>> 2!). The squid at the Tier 1 is the same installation as the
>> Frontier server so if the frontier services goes down so will the
>> backup squid. This does reduce the resilience of the setup
>> slightly but I think this is worth it given it should make things
>> significantly simpler to maintain. It does also means I will have
>> to get the SAM test modified slightly. If however there are sites
>> that are happy with the current setup and managing firewall access
>> to their squid from other sites worker nodes then please feel free
>> to respond.
>>
>> Before committing any change to Tiersofatlas I would like sites to
>> run a test to make sure they can indeed successfully access the
>> RAL squid.
>>
>> To do this:
>> Log into a WN
>> > wget http://frontier.cern.ch/dist/fnget.py
>> > export http_proxy=http://lcgft-atlas.gridpp.rl.ac.uk:3128
>> > python fnget.py --url=http://lcgft-atlas.gridpp.rl.ac.uk:3128/
>> frontierATLAS/frontier --sql="SELECT TABLE_NAME FROM ALL_TABLES"
>> This should provide a big list of table names and not a python error!
>>
>> Could sites please reply with the results of the test and any
>> comments are also welcome.
>>
>> Thanks
>>
>> Alastair
>
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