In Druid 0.9, we have refactored the extension loading mechanism. The main reason behind this change is to make Druid load extensions from the local file system without having to download stuff from the internet at runtime (see here for more details).
The following properties have been deprecated:
**druid.extensions.loadList** specifies the list of extensions that will be loaded by Druid at runtime. An example would be
**druid.extensions.directory** specifies the directory where all the extensions live. An example would be
**druid.extensions.hadoopDependenciesDir** specifies the directory where all the Hadoop dependencies live. An example would be
**druid.extensions.hadoopDependenciesDir=/xxx/hadoop-dependencies.** Note: We didn’t change the way of specifying which Hadoop version to use. So you just need to make sure the Hadoop you want to use exists underneath /xxx/hadoop-dependencies.
You might now wonder if you have to manually put extensions inside
**/xxx/hadoop-dependencies**. The answer is no, we already have created them for you. Download the latest Druid tarball at http://druid.io/downloads.html. Unpack it and you will see
**hadoop-dependencies** folders there. Simply copy them to
**/xxx/hadoop-dependencies** respectively, now you are all set!
If the extension or the Hadoop dependency you want to load is not included in the core extension, you can use pull-deps to download it to your extension directory.
If you want to load your own extension, you can first do **mvn install **to install it into local repository, and then use pull-deps to download it to your extension directory.
Please feel free to leave any questions regarding the migration.