IBM Support

IT32639: JMS ConnectionFactory property CNLIST does not work in Apache Tomcat

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APAR status

  • Closed as program error.

Error description

  • A JMS connection factory has been defined within Apache Tomcat,
    and uses the CNLIST property to specify a connection name list
    to connect to a multi-instance queue manager, as shown below:
    
      < Resource name="jms/ConnectionFactory"
           auth="Container"
           CHAN="CHANNELNAME"
           QMGR="QMGRNAME"
           CNLIST="Host1(2000),Host2(2000)"
           ... ...>
    
    However, when an application uses the connection factory to
    create a connection, a JMSException containing the following
    message is thrown:
    
    JMSWMQ0018: Failed to connect to queue manager 'QMGRNAME' with
    connection mode 'Client' and host name 'localhost(1414)'.;
    nested exception is com.ibm.mq.MQException: JMSCMQ0001: IBM MQ
    call failed with compcode '2' ('MQCC_FAILED') reason '2538'
    ('MQRC_HOST_NOT_AVAILABLE').
    

Local fix

  • Specify the connection name list using the property CRSHOSTS,
    instead of CNLIST.
    

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    This issue affects users of the IBM MQ classes for JMS that:
    
    - Have defined JMS connection factories in Apache Tomcat, where
    the connection factory definition contains the CNLIST
    (Connection name list) property.
    - And have applications running inside Apache Tomcat which use
    that connection factory to connect to a queue manager.
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    When an MQ connection factory is stored in a JNDI repository,
    the MQ classes for JMS will:
    
    - Construct a javax.naming.Reference object containing a number
    of name/value pairs representing the properties of the factory.
    - And pass the Reference object to the JNDI provider to be
    stored in the repository.
    
    When the connection factory is looked up from JNDI, the JNDI
    provider passes the Reference back to the MQ classes for JMS.
    The MQ classes for JMS read the properties contained within the
    Reference to rebuild the MQ connection factory for the
    application to use.
    
    Now, the Connection Factory property CNLIST (Connection name
    list) allows users to specify a comma-separated list of
    "hostname(port)" pairs, where each pair contains:
    
    - The hostname of the system where the queue manager is running.
    - And the port that the listener associated with that queue
    manager is using.
    
    In most environments, when this property is set on a connection
    factory, the MQ classes for JMS create a new internal property
    on the connection factory called CRSHOSTS, and set its value to
    the same value of the CNLIST property. The CRSHOSTS property is
    then added to the Reference object that is stored in JNDI. When
    the MQ classes for JMS reconstruct the connection factory from
    the Reference, they check if the CRSHOSTS property has been set
    - if it has, then the connection name list for the factory is
    set to the value of CRSHOSTS. If it has not been set, then the
    connection name list property is left at its default value of
    "localhost(1414)".
    
    However, when an MQ connection factory was defined with Apache
    Tomcat, it was possible that the Reference object stored in JNDI
    had the CNLIST property set on it, rather than CRSHOSTS. In this
    situation, when the MQ classes for JMS rebuilt the connection
    factory from the Reference, the connection name list was not set
    on it. As a result, when an application created a JMS connection
    from the connection factory, the MQ classes for JMS tried to
    connect to an instance of the queue manager running on the
    system with hostname "localhost" and using port 1414. This
    attempt failed and a JMSException containing the following
    message was thrown back to the application:
    
    JMSWMQ0018: Failed to connect to queue manager '<queue manager
    name>' with connection mode 'Client' and host name
    'localhost(1414)'.;
    nested exception is com.ibm.mq.MQException: JMSCMQ0001: IBM MQ
    call failed with compcode '2' ('MQCC_FAILED') reason '2538'
    ('MQRC_HOST_NOT_AVAILABLE').
    

Problem conclusion

  • The MQ classes for JMS have been updated so that when a
    Reference object representing an MQ connection factory is
    retrieved from a JNDI repository, the following steps will now
    be performed:
    
    - Initially check to see if the Reference contains the CRSHOSTS
    property.
    - If it does:
        - Set the connection name list to the value of CRSHOSTS.
    - Else if the Reference contains the CNLIST property then:
        - Set the connection name list to the value of CNLIST.
    - End if
    
    This ensures that the connection name list will be set on an MQ
    connection factory, if the Reference object looked up from JNDI
    uses either the CNLIST or CRSHOSTS property to store this
    information.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v9.1 CD    TBC.
    v9.1 LTS   9.1.0.7
    
    The latest available maintenance can be obtained from
    'WebSphere MQ Recommended Fixes'
    http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037
    
    If the maintenance level is not yet available information on
    its planned availability can be found in 'WebSphere MQ
    Planned Maintenance Release Dates'
    http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309
    ---------------------------------------------------------------
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT32639

  • Reported component name

    IBM MQ BASE MP

  • Reported component ID

    5724H7271

  • Reported release

    910

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2020-04-23

  • Closed date

    2020-05-29

  • Last modified date

    2020-05-29

  • APAR is sysrouted FROM one or more of the following:

  • APAR is sysrouted TO one or more of the following:

Fix information

  • Fixed component name

    IBM MQ BASE MP

  • Fixed component ID

    5724H7271

Applicable component levels

[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSYHRD","label":"IBM MQ"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Line of Business":{"code":"LOB36","label":"IBM Automation"}}]

Document Information

Modified date:
30 May 2020