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| hooman24 |
 Posted: Sun Jul 30, 2017 10:14 am Post subject: How to connect a client application to multiple servers? |
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Apprentice
Joined: 09 Aug 2014
Posts: 25
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We are going to connect a client application(using MQ Client) to multiple MQ servers. As I understand we should use CCDT for this purpose.
My problem is how should I create CCDT file. since we have multiple MQ servers if I use RUNMQSC and DEF CLNTCONN on one server only it will create a single file for just that MQ Server And It seems that CCDT file is a binary file that could not be edited so that I can add other channel definitions for other MQ servers.
My question is how should I create CCDT file that contains all MQ server channel definitions. |
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| bruce2359 |
| Posted: Sun Jul 30, 2017 2:38 pm Post subject: |
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Poobah
Joined: 05 Jan 2008
Posts: 9470
Location: US: west coast, almost. Otherwise, enroute.
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On a client, use runmqsc -n option to create and maintain a ccdt on that client.
Some IT shops dedicate qmgr instance solely to create ccdt's. The admin can then rename the ccdt, and export it to a specific client or clients. This is my favorite ccdt admin method.
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| gbaddeley |
| Posted: Sun Jul 30, 2017 4:08 pm Post subject: |
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Jedi Knight
Joined: 25 Mar 2003
Posts: 2538
Location: Melbourne, Australia
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| bruce2359 wrote: |
On a client, use runmqsc -n option to create and maintain a ccdt on that client.
Some IT shops dedicate qmgr instance solely to create ccdt's. The admin can then rename the ccdt, and export it to a specific client or clients. This is my favorite ccdt admin method. |
We use dedicated temporary qmgrs. The qmgr is created & started, define channel commands are run, take a copy of CCDT file (/var/mqm/qmgrs/QMGRNAME/@ipcc/AMQCLCHL.TAB) to a name based on the app, then stop & delete the qmgr. It only takes a few seconds. There are programs available that allow CCDTs to be created and edited, but we've stuck with this legacy method that works out of the box.
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Glenn |
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| PaulClarke |
| Posted: Sun Jul 30, 2017 4:41 pm Post subject: |
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Grand Master
Joined: 17 Nov 2005
Posts: 1002
Location: New Zealand
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hooman24,
Just to be clear, in case the previous answers still left some doubt. When you define a CCDT on a Queue Manager there is no restriction that all created CLNTCONN definitions must point to the Queue Manager you are making the definition on. So, on QMA you can define CLNTCONN channels that point to QMB, QMC, QMD etc. Clearly any SVRCONN channels you define must belong to that Queue Manager but not CLNTCONNs.
The only other thing to be aware of is to define your CLNTCONNs on a Queue Manager that is not newer than your client machines.
Cheers,
Paul.
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Paul Clarke
MQGem Software
www.mqgem.com |
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| hooman24 |
| Posted: Sun Jul 30, 2017 9:12 pm Post subject: |
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Apprentice
Joined: 09 Aug 2014
Posts: 25
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| Thanks for all of the replies. REALLY helpful. |
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| rammer |
| Posted: Mon Jul 31, 2017 12:07 am Post subject: |
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Partisan
Joined: 02 May 2002
Posts: 359
Location: England
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| PaulClarke wrote: |
The only other thing to be aware of is to define your CLNTCONNs on a Queue Manager that is not newer than your client machines.
Paul. |
Morning, Fully understand the statement but in real life is that practical?
Its possible many people are running MQ 8 for example and have client connections connecting in from old versions of Client. In this case is there a compatibility option for older versions of clients?
You can see the issue that Central System upgrade MQ Server but clients and customers are unwilling to pay for upgrade of client software and testing etc?
Thanks in advance |
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| zpat |
| Posted: Mon Jul 31, 2017 12:16 am Post subject: |
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Jedi Council
Joined: 19 May 2001
Posts: 5866
Location: UK
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Support pac MO72 has an option to generate the CCDT at a particular level such as v6, or v7.
This might serve as a means to generate versions CCDTs for older clients.
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| exerk |
| Posted: Mon Jul 31, 2017 3:07 am Post subject: |
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Jedi Council
Joined: 02 Nov 2006
Posts: 6339
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Additionally, there is THIS TECHNOTE, an abstract of which states:
Update on July 2016:
There are 2 APARs that allow OLDER MQ clients to use NEWER CCDT files!
These APARs relax the restriction by allowing newer CCDTs to be used on older clients but with the caveat that the older client cannot make use of any of the newer channel attributes. These attributes will assume their default values when the CCDT is negotiated with the queue manager.
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| mqjeff |
| Posted: Mon Aug 07, 2017 7:09 am Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 17447
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... what do you mean by "connect to multiple MQ servers"?
Do you mean "only one at a time, but maybe a different one at different times" ?
Or do you mean "many at the same time"?
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