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Version: v1.26.x LTS

Troubleshooting z/OS Services

Troubleshooting z/OS Services

The following topics contain information that can help you troubleshoot problems when you encounter unexpected behavior installing and using Zowe™ z/OS Services.

z/OSMF JVM cache corruption#


When you work with Zowe, there are situations when z/OSMF abends.

The following is a snippet from the Java core dump.

CEE3DMP V2 R4.0: Condition processing resulted in the unhandled condition.   ...  Condition Information for Active Routines    Condition Information for  (DSA address 0000005F026FDE40)      CIB Address: 0000005F026FA1E8      Current Condition:        CEE0198S The termination of a thread was signaled due to an unhandled condition.      Original Condition:        CEE3250C The system or user abend SDC2  R=4A001620 was issued.      Location:        Program Unit:  Entry: ntv_createJoinWorkUnit        Statement:     Offset: +000ABD14      Machine State:        ILC..... 0002    Interruption Code..... 000D        PSW..... 0785240180000000 000000003825D954


The error occurs when the Java runtime being used by the z/OSMF Liberty server and the Java runtimes being used by Zowe share a user ID of IZUSVR1, which results in a collision. To resolve this issue, review the following steps.

  1. Isolate the started task user IDs
  2. Update z/OSMF to not use JVM class caching

Isolate the started task user IDs#

The z/OSMF started task IZUSVR1 runs under the user ID of IZUUSER. Before version 1.9 of Zowe, its started task ZWESVSTC also ran under the same user ID. With Zowe 1.9, the default configuration changed to use a new user ID of ZWESVUSR and group of ZWEADMIN.

If your started task ZWESVSTC is configured to run under the user ID IZUUSER, change it to run under user ID ZWESVUSR. For more information, see Configuring the z/OS System for Zowe.

Update z/OSMF to not use JVM class caching#

If you need to run ZWESVSTC under the same user ID as z/OSMF for your environment, you can update the z/OSMF configuration to switch off shared class caching which stops the crash from occurring. Disabling shared class caching reduces the performance of z/OSMF so the preferred fix is to change the user ID of ZWESVSTC away from IZUUSER to ZWESVUSR as described above.

Navigate to the file /var/zosmf/configuration/local_override.cfg. This contains the startup arguments for the Java runtime used by z/OSMF. Add the following line:


You will need to recycle the z/OSMF server running, which by default will be running under the started task IZUSVR1.

For more information on the effect that disabling a shared class cache has on a Java runtime, see Class data sharing in the IBM Knowledge Center.

Unable to generate unique CeaTso APPTAG#


When you request a Zowe data set or z/OS Files API, you receive a response code 500 - 'Internal Server Error', with a message "Unable to generate unique CeaTso APPTAG".


Check z/OSMF settings of REST API of file. You must define RESTAPI_FILE in IZUPRMxx by the following statement:


The default IZUFPROC can be found in SYS1.PPROCLIB. And the proper authorization is needed to get IZUFPROC work successfully.

z/OS Services are unavailable#

If the z/OS Services are unavailable, take the following corrective actions.

  • Ensure that the z/OSMF REST API services are working. Check the z/OSMF IZUSVR1 task output for errors and confirm that the z/OSMF RESTFILES services are started successfully. If no errors occur, you can see the following message in the IZUSVR1 job output:

    CWWKZ0001I: Application IzuManagementFacilityRestFiles started in n.nnn seconds.

    To test z/OSMF REST APIs you can run curl scripts from your workstation.

    curl --user <username>:<password> -k -X GET --header 'Accept: application/json' --header 'X-CSRF-ZOSMF-HEADER: true' "https://<z/os host name>:<securezosmfport>/zosmf/restjobs/jobs?prefix=*&owner=*"

    where the securezosmfport is 443 by default. You can verify the port number by checking the izu.https.port variable assignment in the z/OSMF file.

    If z/OSMF returns jobs correctly, you can test whether it is able to returns files by using the following curl scripts:

    curl --user <username>:<password> -k -X GET --header 'Accept: application/json' --header 'X-CSRF-ZOSMF-HEADER: true' "https://<z/os host name>:<securezosmfport>/zosmf/restfiles/ds?dslevel=SYS1"

    If the restfiles curl statement returns a TSO SERVLET EXCEPTION error, check that the the z/OSMF installation step of creating a valid IZUFPROC procedure in your system PROCLIB has been completed. For more information, see the z/OSMF Configuration Guide.

    The IZUFPROC member resides in your system PROCLIB, which is similar to the following sample:

    //IZUFPROC PROC ROOT='/usr/lpp/zosmf'  /* zOSMF INSTALL ROOT     *///IZUFPROC EXEC PGM=IKJEFT01,DYNAMNBR=200                          //SYSEXEC  DD DISP=SHR,DSN=ISP.SISPEXEC                            //         DD DISP=SHR,DSN=SYS1.SBPXEXEC                           //SYSPROC  DD DISP=SHR,DSN=ISP.SISPCLIB                            //         DD DISP=SHR,DSN=SYS1.SBPXEXEC                           //ISPLLIB  DD DISP=SHR,DSN=SYS1.SIEALNKE                           //ISPPLIB  DD DISP=SHR,DSN=ISP.SISPPENU                            //ISPTLIB  DD RECFM=FB,LRECL=80,SPACE=(TRK,(1,0,1))                //         DD DISP=SHR,DSN=ISP.SISPTENU                            //ISPSLIB  DD DISP=SHR,DSN=ISP.SISPSENU                            //ISPMLIB  DD DISP=SHR,DSN=ISP.SISPMENU                            //ISPPROF  DD DISP=NEW,UNIT=SYSDA,SPACE=(TRK,(15,15,5)),            //         DCB=(RECFM=FB,LRECL=80,BLKSIZE=3120)                     //IZUSRVMP DD PATH='&ROOT./defaults/izurf.tsoservlet.mapping.json'  //SYSOUT   DD SYSOUT=H                                              //CEEDUMP  DD SYSOUT=H                                              //SYSUDUMP DD SYSOUT=H                                              //                                                                 

    Note: You might need to change paths and data sets names to match your installation.


  • Check your system console log for related error messages and respond to them.