Upgrading CICS with a running workload

The scenario uses the abilities of CICSPlex® SM to route work to any available target region, and to continue to route work, even when the maintenance point CMAS is offline. It is possible to upgrade only the CICSPlex SM component and defer the upgrade of CICS®. This scenario upgrades both at the same time.

One LPAR is upgraded first, then the other. In outline, the solution has these steps:

  1. Shut down, upgrade and restart the maintenance point CMAS and WUI.
  2. Quiesce each AOR as a workload target. When there are no longer running tasks, shut down and upgrade each AOR. Do not yet restart.
  3. Deregister each TOR from generic VTAM®. When no terminals are connected for that TOR and no work remains for that TOR, shut down and upgrade the TOR. Do not yet restart.
  4. Upgrade any remaining CMAS in the LPAR.
  5. Restart all CMAS.
  6. Restart all AORs.
  7. Restart all TORs.
  8. Repeat for the second LPAR.

Initial configuration

Figure 1. Initial configuration
The diagram shows two logical partitions (LPARs), in which CICS workload is running. LPAR 1 contains the maintenance CMAS and WUI. Both LPARs contain routing regions (TORs) that are connected to a number of target CICS regions (AORs).

To streamline the diagrams, connections between LPARs are not shown.

There are two logical partitions (LPARs), with a shared CICS system definition file (CSD):

LPAR 1 is running CICS TS for z/OS® and CICSPlex SM 4.2. It has:
  • Two CICPlex SM address spaces (CMAS), one of which is the maintenance CMAS. The CMAS on this LPAR connects to both the maintenance point CMAS and the CMAS on LPAR 2.
  • Three terminal-owning regions (TORs). These regions are linked to application-owning regions (AORs) in LPAR 2.
  • A WUI server.
  • Ten application-owning regions (AORs). These regions are linked to terminal-owning regions (TORs) in LPAR 2.
LPAR 2 is also running CICS TS for z/OS and CICSPlex SM 4.2. It has:
  • One CICSPlex SM address space (CMAS). This CMAS connects to the two CMAS on LPAR 1.
  • Three terminal-owning regions (TORs). These regions are linked to application-owning regions (AORs) in LPAR 1.
  • Ten application-owning regions (AORs). These regions are linked to terminal-owning regions (TORs) in LPAR 1.

Both sets of TORs are defined with the same z/OS Communications Server generic resource. This means that, when the regions are shut down on one LPAR, the work should transfer to the regions on the second LPAR. CICSPlex SM can pass work that comes in to a TOR to any available AOR. This means that, each TOR connects to every AOR.

Back up any data sets that you need to retain

Before you start any upgrade, you should back up any data sets that you need to retain. These data sets can include CICS system definition data sets (CSDs) and exported WUI repositories.

Upgrade the first LPAR

In this section, you upgrade one LPAR completely, then start the upgrade on the second LPAR. If you are not running a WUI server, ignore the steps that refer to it.

  1. Shut down the maintenance point CMAS. For more details, see Shutting down a CMAS. The CICS workload continues to run, even without the maintenance CMAS.
  2. Upgrade both CICS TS for z/OS and CICSPlex SM to the latest level.
  3. If you have a WUI, shut down the WUI server and upgrade it to the latest level.
  4. Start the maintenance point CMAS.
  5. If you have a WUI, restart the WUI. In the WUI or CICS Explorer®, you can see the CMAS and WUI at the latest level of CICS and CICSPlex SM.
    Figure 2. The outcome of the procedure so far: the CMAS and WUI are upgraded.
    The diagram shows the result of the procedure so far. The maintenance point CMAS and the optional WUI server in LPAR 1 are upgraded.
  6. For each AOR:
    1. Quiesce the AOR from the workload. Check that all work that was running in that region is complete. For details, see Quiescing a target region in an active workload.
    2. Shut down the AOR.
    3. Upgrade the AOR to the latest levels of CICS and CICSPlex SM. Do not restart the AOR.
    The target regions are upgraded as shown in the diagram.
    Figure 3. The outcome of the previous step: the AORs are upgraded.
    The diagram shows the result of the previous step. The target regions in LPAR 1 are upgraded.
  7. For each TOR:
    1. Deregister the router as a VTAM generic resource (SET VTAM DEREGISTERED). Set close communications with VTAM (SET VTAM CLOSED), making the TOR unavailable to incoming work. For details, see Removing a TOR from a generic resource.
    2. When all work that is running in the region is complete, close the TOR.
    3. Upgrade the TOR to the latest levels of CICS and CICSPlex SM. Do not restart the TOR.
    The routing regions are upgraded as shown in the diagram.
    Figure 4. The outcome of the previous step: the TORs are upgraded.
    The diagram shows the result of the previous step. The routing regions in LPAR 1 are upgraded.
  8. Shut down any remaining CMAS.
  9. Upgrade the remaining CMAS. You can see that only the maintenance point CMAS, and WUI if present, are running in this LPAR. The TORs and AORs are upgraded but are not yet started. The second LPAR is still fully active.
    Figure 5. The outcome of the previous step: all elements are upgraded in LPAR 1 but not yet all started.
    The diagram shows the result of the previous step. All elements in LPAR 1 are upgraded but are not yet all running.
  10. Restart the remaining CMAS. For details, see Restarting a CMAS.
  11. When the CMAS are active, restart each TOR.
  12. Restart each AOR.
Work is coming into the routing regions on both LPARs. It is routed to target regions in both LPARs. You can now upgrade the second LPAR while the workload continues to run in the first one.
Figure 6. Upgrade is complete on LPAR 1
The diagram shows the result of the previous step. All elements in LPAR 1 are upgraded and are restarted.

Upgrade the second LPAR

When work is flowing again in the first LPAR, you can upgrade the second one.

  1. For each AOR:
    1. Quiesce the AOR from the workload. Check that all work that was running in that region completed. For details, see Quiescing a target region in an active workload.
    2. Shut down the AOR.
    3. Upgrade the AOR to the latest levels of CICS and CICSPlex SM. Do not restart the AOR.
  2. For each TOR:
    1. Deregister the router as a VTAM generic resource (SET VTAM DEREGISTERED). Set close communications with VTAM (SET VTAM CLOSED), making the TOR unavailable to incoming work. For details, see Quiescing a target region in an active workload.
    2. When all work that is running in the region is complete, close the TOR.
    3. Upgrade the TOR to the latest levels of CICS and CICSPlex SM. Do not restart the TOR.
  3. Upgrade the remaining CMAS.
  4. Restart the remaining CMAS. For details, see Restarting a CMAS.
  5. When the CMAS is active, restart each TOR.
  6. Restart each AOR.
Work is coming into the routing regions on both LPARs. It is routed to target regions in both LPARs.
Figure 7. The upgrade is complete across both LPARs.
The diagram shows the result of the procedure. All elements in LPAR 2 are upgraded and are restarted.