Preparing for high availability

Edit online

UMS offers high availability features through Zowe with an active/passive mode, whereas most other Zowe processes use active/active.

For UMS to support high availability:
  • The API Mediation Layer (gateway component) must be enabled.
  • The external host and port specified for the API Mediation Layer in zowe.yaml must point to the DVIPA address, which is set up according to Configuring Sysplex for high availability from the Zowe documentation.
  • The DVIPA address must be specified in the parameter components.izp.server.host.

To run UMS under Zowe high availability mode, configure DVIPA with the UMS main HTTP port defined as "hot standby", listing the UMS IP addresses of the machines that are running Zowe.

The high availability instance name specified in the Zowe haInstances parameter will be included in the UMS log file name located in the UNIX System Services zowe.logDirectory.

Note: If there is any unexpected application behavior, exit the UMS screen within the Zowe application manager and reopen the UMS application after a few seconds for the backup process to finish initializing.

A sample DVIPA configuration is shown below.

VIPADYNAMIC                                           
  VIPADEFINE       <DVIPA mask> <DVIPA IP address>
    VIPADISTRIBUTE                                         
       DISTMETHOD HOTSTANDBY <DVIPA IP address> PORT <UMS port>                         
       DESTIP                                              
          <IP-address-1> PREFERRED                            
          <IP-address-2> BACKUP                               
ENDVIPADYNAMIC

In addition to the UMS port, the ZSS port should also be configured with DVIPA, and the DVIPA address should be selected as the first element in the Zowe externalDomains host array.

To use high availability, MFA_JWT authentication is required. However, the users are not required to be MFA users. The MFA_JWT authentication type invokes the API Mediation Layer Single Sign-On (SSO) mechanism that is leveraged by UMS high availability. For details on configuring the authType parameter to enable Zowe API Mediation Layer, refer to Configuring multifactor authentication for UMS.
Notes:
  • If UMS is switching to the backup server when the active server is no longer available, the user will briefly experience unexpected behaviors, including access denied error messages and changing menu items. You need to exit the UMS application within Zowe and reopen it to fix the issue.
  • Db2® DevOps Experience and IMS Administration Foundation do not support the UMS high availability configuration.