18.104.22.168. Main Configuration¶
For its main configuration, WebMapReduce uses a scheme similar to Hadoop’s:
- Default settings are stored in a file named wmr-default.xml.
- Site-specific are stored in in wmr-site.xml.
Both of these files are usually stored in the $WMR_HOME/conf directory, and they have the exact same format and features as Hadoop’s configuration files.
First, make sure that the file wmr-site.xml exists in the $WMR_HOME/conf directory. If one is not present, copy/rename it from the file wmr-site.xml.example:
$ cp $WMR_HOME/conf/wmr-site.xml.example $WMR_HOME/conf/wmr-site.xml
Next, we will set the hostname and port to which the server should bind, if the defaults will not work (localhost and 50100, respectively). Open wmr-site.xml and add these two stanzas inside the <configuration> tag:
<property> <name>wmr.server.bind.host</name> <value>HOSTNAME-OR-IP</value> </property> <property> <name>wmr.server.bind.port</name> <value>PORT</value> </property>
Replace HOSTNAME-OR-IP and PORT with the appropriate values.
On many systems, binding to localhost will not allow the server to accept outside connections. If you plan to run your frontend on another machine, setting wmr.server.bind.host to 0.0.0.0 is the easiest way to allow it to connect.
Those settings should be enough for a first run of WebMapReduce. Other settings that might be of interest at this point are wmr.dfs.home and wmr.temp.dir. You may wish to change the arbitrary, internally-used used database password in wmr.db.password to your own random string. The settings beginning with wmr.quota. are used to configure the number of jobs a user may submit at a particular time. Look at wmr-default.xml for a full list of possible settings and their descriptions. Some of these will be covered in later sections.