What is the function of getLocalCacheArchives method

Question

I am new to Java & Hadoop. I was going through a DistributedCache MapReduce program. In the program in code, I found a setup method and I couldn’t understand the below code.

Configuration conf = context.getConfiguration();

Path[] localpath = DistributedCache.getLocalCacheArchives(conf);

Can anyone help me in understanding the getLocalCacheArchives() method. I tried but couldn’t find the method in MapReduce documentation.

Answer 1

We use distributed cache to share those files which are needed by all nodes across the cluster. The file is made available to all the slave node before the execution of MapReduce code.

In the main method (addCacheFile) we share those files that is to be shared across the cluster, whereas in the setup method we retrieve those files using getLocalCacheArchives() method.

Go through this distributed cache official documentation:

https://hadoop.apache.org/docs/r2.6.1/api/org/apache/hadoop/filecache/DistributedCache.html