Creating a JAAS configuration file

Certain applications, such as those using the SolrJ library, require a Java Authentication and Authorization Service (JAAS) configuration file.

If you are authenticating using kinit to obtain credentials, you can configure the client to use your credentials cache by creating a JAAS file with the following contents:
```
Client {
 com.sun.security.auth.module.Krb5LoginModule required
 useKeyTab=false
 useTicketCache=true
 principal="[***USER***]@[***REALM***]";
 };
```

If you want the client application to authenticate using a keytab, create a JAAS file with the following contents:

Client {
 com.sun.security.auth.module.Krb5LoginModule required
 useKeyTab=true
 keyTab="[***PATH/TO/USER.KEYTAB***]"
 storeKey=true
 useTicketCache=false
 principal="[***USER***]/[***HOST NAME***]@[***REALM***]";
};

[***USER***]: is a valid user name in your environment
/[***HOST NAME***]: If you use a service principal that includes the host name, make sure that it is included in the jaas.conf file (for example, solr/solr01.example.com@EXAMPLE.COM).
[***REALM***]: is your Kerberos realm
[***PATH/TO/USER.KEYTAB***]: is the path to the keytab file you want to use