Configuring the Caching Service for high availability

Zowe can work in a high availability (HA) configuration where multiple instances of the Zowe launcher are started, either on the same LPAR, or different LPARs connected through sysplex distributor. If you are only running a single Zowe instance on a single LPAR you do not need to create a caching service so you may skip this step.

In an HA setup the different Zowe API Mediation Gateway servers share the same northbound port (by default 7554), and client traffic to this port is distributed between separate gateways that in turn dispatch their work to different services. When any of the services individually become unavailable the work can be routed to available services, which means that the initial northbound request will be fulfilled.

Zowe uses the Caching Service to centralize the state data persistent in high availability (HA) mode. If you are runnning the caching service on z/OS there are three storage methods: inMemory, infinispan or VSAM. If you are running the caching service off platform, such as a Linux or Windows container image, it is also possible to specify redis or infinispan.

To learn more about how the Caching Service can be used, see Using the Caching Service.

note

The Infinispan storage method is recommended for production usage.

inMemory

This storage method is designed for quick start of the service and should be used only for single instance scenario and development or test purpose. Do not use it in production or high availability scenario.

To use this method, set the zowe.components.caching-service.storage.mode value to inMemory in the zowe.yaml configuration file. When this method is enabled, the Caching Service will not persist any data.

zowe
  components:
    caching-service:
      enabled: true
      port: 7555
        storage:
          evictionStrategy: reject
          mode: imMemory
          size: 10000

Infinispan

Infinispan is designed to be run mainly on z/OS since it offers good performance. To enable this method, set the value of zowe.components.caching-service.storage.mode to infinispan in the zowe.yaml configuration file. Infinispan environment variables are not currently following the v2 naming convention, so they must be defined into zowe.environments section. For more information on these properties and their values see Infinispan configuration.

zowe
  components:
        caching-service:
          storage:
            mode: infinispan
            infinispan: 
              jgroups:
                port: 7098

VSAM

This storage method allows you tu use VSAM dataset as a storage for Caching service. You can use zwe init vsam command to generate proper dataset.

The command zwe init vsam uses the template JCL in SZWESAMP(ZWECSVSM). You can edit and submit this yourself, or else if use zwe init vsam which will copy the source template member from zowe.setup.mvs.hlq.SZWESAMP(ZWECVCSM) and create a target JCL member in zowe.setup.mvs.jcllib(ZWECVSCM) with values extracted from the zowe.yaml file.

zowe:
  setup:
    mvs:
      hlq: IBMUSER.ZWE
      jcllib: IBMUSER.ZWE.CUST.JCLLIB
    vsam:
      mode: NONRLS
      volume: VOL123
      storageClass:
  components:
    caching-service:
      storage:
        mode: VSAM
        vsam:
          name: IBMUSER.ZWE.CUST.CACHE

• zowe.components.caching-service.storage.vsam.name
  This specifies the data set name that the ZWECSVSM JCL will create. This is used to replace all occurrences of #dsname in the ZWECSVSM data set.

  note

  The ZWECSVSM JCL defines the key length and record length of the VSAM instance. If the key length and record length of this JCL is changed, zowe.environments.CACHING_STORAGE_VSAM_KEYLENGTH and zowe.environments.CACHING_STORAGE_VSAM_RECORDLENGTH must be set to the new values.

• zowe.components.caching-service.storage.mode
  This specifies whether you would like to use Record Level Sharing (RLS) for your VSAM data set. RLS is recommended for Sysplex deployment. NONRLS is also an allowed value.

• zowe.setup.vsam.storageClass
  If you use the RLS mode, a storage class is required.

• zowe.setup.vsam.volume
  If you set to use the NONRLS mode, a storage volume is required.

To preview the member before submitting it, use the value --security-dry-run. Otherwise, the command automatically submits the JCL and waits for its completion.

>zwe init vsam -c ./zowe.yaml
-------------------------------------------------------------------------------
>> Create VSAM storage for Zowe Caching Service
Modify ZWECSVSM
- IBMUSER.ZWE.CUST.JCLLIB(ZWECSVSM) is prepared
Submit USER.ZWEV2.CUST.JCLLIB(ZWECSVSM)
- Job ZWECSVSM(JOB05407) ends with code 0 (COMPLETED).
>> Zowe Caching Service VSAM storage is created successfully.
>

redis

Redis is not available if you are running the API Mediation Layer on z/OS under Unix System Services. Usage of redis is intended for when API ML is running off platform, such as in a Linux or Windows container as part of a hybrid cloud deployment.

To enable this method, set the value of zowe.components.caching-service.storage.mode to redis in the zowe.yaml configuration file. There are a number of values to control the redis nodes, sentinel and ssl properties that need to be set in the zowe.yaml file. For more information on these properties and their values see Redis configuration.

zowe:
  components:
    caching-service:
    enabled: true
      port: 7555
        storage:
          size: 10000
          evictionStrategy: reject
          mode: redis
          redis:
            masterNodeUri: 
            timeout: 60
          sentinel:
            masterInstance
            nodes
          ssl:
            enabled: true
            keystore:
            keystorePassword:
            trustStore:
            trustStorePassword