PATCH INSTALLATION PROCEDURE:

Date: 2007-08-08
Name: Subscription Service Fixes.



=INTRODUCTION:

This patch fixes some bugs in connection with the usage of the NG/AMS
Data Subscription Service together with Oracle + fixes some bugs in 
general in connection with this service.

In the following these terms are used to describe the actors in connection
with the Subscription Services:

1. Data Distributor/Server Side: The NGAS Nodes from where data should be
distributed to the client nodes requesting this.

2. Suscriber Nodes: The NGAS Nodes that subscribe for data from the Data 
Distributor.


Note: If a Subscriber Node is temporarily unavailable, e.g. due to 
maintenance, the data for that node will be back-log buffered on the Data
Distributor and delivered when the client becomes available (goes online)
again.



=SOFTWARE UPGRADE:
Note, although this SW patch is only necessary on the Data Distributor Nodes,
it is recommended to install it on all NGAS Nodes in the system for 
consistency.


To install this patch on an NGAS Node running ALMA/NGAS V3.2, do as follows:


- Back-up existing source files:

$ cp /opsw/packages/ARCHIVE/NGAS/ngams/ngamsLib/ngamsDbBase.py \
/opsw/packages/ARCHIVE/NGAS/ngams/ngamsLib/ngamsDbBase.py.org

$ cp /opsw/packages/ARCHIVE/NGAS/ngams/ngamsServer/ngamsSubscriptionThread.py \
/opsw/packages/ARCHIVE/NGAS/ngams/ngamsServer/ngamsSubscriptionThread.py.org



- Download the tarball containing the patched files from the URL:

http://www.eso.org/~jknudstr/NGAS/ALMA/RELEASES/PATCHES/2007-08-08/NGAS_V3_2-ALMA_patch_2007-08-08.tar.gz

(MD5 checksum: 36cbad0dd61816287c3cdabf530c68b0)



- Untar the patch tarball, it will replace two files:

/opsw/packages/ARCHIVE/NGAS/ngams/ngamsLib/ngamsDbBase.py
/opsw/packages/ARCHIVE/NGAS/ngams/ngamsServer/ngamsSubscriptionThread.py



=CONFIGURATION CHANGES:
In order to enable the Subscription Service, the configuration files on the
Distributer and the Subscriber Nodes have to be changed and the NGAMS servers
subsequently restarted.


- On the Data Distributor Nodes, do the following:

-- Open the configuration file: 

$ <editor> /etc/ngamsServer.conf

-- Locate the "SubscriptionDef" configuration element and edit so that
it looks like this:


  <SubscriptionDef AutoUnsubscribe="0"
                   SuspensionTime="0T00:03:00"
                   BackLogExpTime="7T00:00:00"
                   Enable="1">
  </SubscriptionDef>



- On the Data Subscriber Nodes, do the following:

-- Open the configuration file: 

$ <editor> /etc/ngamsServer.conf

-- Locate the "SubscriptionDef" configuration element and edit so that
it looks like this:


  <SubscriptionDef AutoUnsubscribe="0"
                   SuspensionTime="0T00:03:00"
                   BackLogExpTime="7T00:00:00"
                   Enable="1">
    <Subscription HostId="almadev1"
                  PortNo="8181"
                  Priority="0"
                  SubscriberUrl="http://ga004786:8181/ARCHIVE"
                  FilterPlugIn=""
                  FilterPlugInPars=""/>
  </SubscriptionDef>


Note: 
--- For each Data Distributor Node, there should be a "Subscription"
configuration element.
--- The parameters "HostId" and "PortNo" should be updated to match those
of each Data Distributor Node.
--- The parameter "SubscriberUrl" should be updated to match the URL of each
Subscription Node (local NGAS URL).



- Restart the NG/AMS Servers on each node where the configuration was 
changed:

$ sudo /etc/init.d/ngamsServer restart



- Verify that incoming data on the Distributor Nodes is delivered to the
Subscription Nodes.



# EOF