Accessing the Oozie server with the Oozie Client

The Oozie client is a command-line utility that interacts with the Oozie server using the Oozie web-services API.

Use the /usr/bin/oozie script to run the Oozie client.
For example, if you want to invoke the client on the same machine where the Oozie server is running:
```
$ oozie admin -oozie http://localhost:11000/oozie -status
System mode: NORMAL
```
To make it convenient to use this utility, set the environment variable OOZIE_URL to point to the URL of the Oozie server. Then you can skip the -oozie option.
For example, if you want to invoke the client on the same machine where the Oozie server is running, set the OOZIE_URL to http://localhost:11000/oozie.
```
$ export OOZIE_URL=http://localhost:11000/oozie
$ oozie admin -version
Oozie server build version: 4.0.0-cdh5.0.0
```
important
If Oozie is configured with Kerberos Security enabled:
- You must have a Kerberos session running. For example, you can start a session by running the kinit command.
- Do not use localhost as in the above examples.
As with every service that uses Kerberos, Oozie has a Kerberos principal in the form <SERVICE>/<HOSTNAME>@<REALM>. In a Kerberos configuration, you must use the <HOSTNAME> value in the Kerberos principal to specify the Oozie server; for example, if the <HOSTNAME> in the principal is myoozieserver.mydomain.com, set OOZIE_URL as follows:
```
export OOZIE_URL=http://myoozieserver.mydomain.com:11000/oozie
```
If you use an alternate hostname or the IP address of the service, Oozie will not work properly.