Starting the resolver

Prior to starting the resolver, you must have a user ID defined for the resolver started procedure that includes an OMVS segment, so that the resolver can use z/OS® UNIX services. For information about defining and assigning a user ID for started procedures, see z/OS Security Server RACF Security Administrator's Guide.

Requirement: If the resolver user ID does not have an OMVS segment and you are not using the automatic assignment of unique UNIX identities support to automatically generate OMVS segments, you must explicitly configure an OMVS segment for the resolver user ID. For more information about RACF® and z/OS UNIX, see z/OS Security Server RACF Security Administrator's Guide.

Guideline: The HOME directory in the OMVS segment for the resolver user ID must be accessible when the resolver is started. Specify the root directory [HOME(/)] to avoid problems.

There are two ways that the resolver can be started:

Use z/OS UNIX to start the resolver
The resolver is started when z/OS UNIX is initialized. This method of starting the resolver ensures that applications that require resolver services are not started before the resolver starts. If you use z/OS UNIX to start the resolver, you can use the default resolver settings (see The default resolver settings), or you can optionally create a start procedure and define the address space (see Customizing the resolver).
Use automation tools to start the resolver
The resolver is started by issuing the MVS™ START operator command. You must customize the resolver to use this starting method; see Customizing the resolver for more information. If you use this method of starting the resolver, then it is possible that an application that needs resolver services (such as INETD) is started before the resolver address space is initialized. In this case, you might need to remove the starting of INETD from the z/OS UNIX /etc/rc file and start INETD with automation after the resolver has initialized.

If you are using z/OS UNIX to start the resolver, then the following actions occur when z/OS UNIX is initialized:

z/OS UNIX uses SUB=MSTR to start the resolver (the resolver does not require JES); for information about SUB=MSTR, see z/OS MVS JCL Reference
z/OS UNIX issues an informational message that contains the name of the procedure that it is starting:
BPXF224I THE RESOLVER_PROC, procname, IS BEING STARTED

Rule: If the RESOLVER_PROC statement is not present or is specified with the procedure name DEFAULT, the procname value is RESOLVER, even though a start procedure was not used. For more information about the RESOLVER_PROC statement, see z/OS MVS Initialization and Tuning Reference.
If the start procedure is not found or if it contains a JCL error, then error messages for the z/OS START command are issued and the resolver address space does not initialize.
If the resolver address space cannot be started, z/OS UNIX initialization continues.