# Configuring Ibis¶

## Ibis global configuration¶

Ibis global configuration happens through the ibis.options attribute. Attributes can be get and set like class attributes.

### Interactive mode¶

Ibis out of the box is in developer mode. Expressions display their internal details when printed to the console. For a better interactive experience, set the interactive option:

ibis.options.interactive = True


This will cause expressions to be executed immediately when printed to the console (or in IPython or the IPython notebook).

### SQL query execution¶

If an Ibis table expression has no row limit set using the limit API, a default one is applied to prevent too much data from being retrieved from the query engine. The default is currently 10000 rows, but this can be configured with the sql.default_limit option:

ibis.options.sql.default_limit = 100


Set this to None to retrieve all rows in all queries (be careful!).

ibis.options.sql.default_limit = None


### Verbose option and Logging¶

To see all internal Ibis activity (like queries being executed) set ibis.options.verbose:

ibis.options.verbose = True


By default this information is sent to sys.stdout, but you can set some other logging function:

def cowsay(x):
print("Cow says: {0}".format(x))

ibis.options.verbose_log = cowsay


## Working with secure clusters (Kerberos)¶

Ibis is compatible with Hadoop clusters that are secured with Kerberos (as well as SSL and LDAP). Just like the Impala shell and ODBC/JDBC connectors, Ibis connects to Impala through the HiveServer2 interface (using the impyla client). Therefore, the connection semantics are similar to the other access methods for working with secure clusters.

Specifically, after authenticating yourself against Kerberos (e.g., by issuing the appropriate kinit commmand), simply pass auth_mechanism='GSSAPI' or auth_mechanism='LDAP' (and set kerberos_service_name if necessary along with user and password if necessary) to the ibis.impala_connect(...) method when instantiating an ImpalaConnection. This method also takes arguments to configure SSL (use_ssl, ca_cert). See the documentation for the Impala shell for more details.

Ibis also includes functionality that communicates directly with HDFS, using the WebHDFS REST API. When calling ibis.hdfs_connect(...), also pass auth_mechanism='GSSAPI' or auth_mechanism='LDAP', and ensure that you are connecting to the correct port, which may likely be an SSL-secured WebHDFS port. Also note that you can pass verify=False to avoid verifying SSL certificates (which may be helpful in testing). Ibis will assume https when connecting to a Kerberized cluster. Because some Ibis commands create HDFS directories as well as new Impala databases and/or tables, your user will require the necessary privileges.

### Default Configuation Values for CDH Components¶

Cloudera CDH ships with HDFS, Impala, Hive and many other components. Sometimes it’s not obvious what default configuration values these tools are using or should be using.

This url https://www.cloudera.com/documentation/enterprise/latest/topics/cdh_ig_ports_cdh5.html#topic_9_1 shows the default configuration values for every component of CDH.