/**
* Simulate the <code>dfs.name.dir</code> or <code>dfs.data.dir</code> of a populated DFS
* filesystem.
*
* <p>This method creates and populates the directory specified by <code>parent/dirName</code>,
* for each parent directory. The contents of the new directories will be appropriate for the
* given node type. If the directory does not exist, it will be created. If the directory already
* exists, it will first be deleted.
*
* <p>By default, a singleton master populated storage directory is created for a Namenode
* (contains edits, fsimage, version, and time files) and a Datanode (contains version and block
* files). These directories are then copied by this method to create new storage directories of
* the appropriate type (Namenode or Datanode).
*
* @return the array of created directories
*/
public static File[] createStorageDirs(NodeType nodeType, String[] parents, String dirName)
throws Exception {
File[] retVal = new File[parents.length];
for (int i = 0; i < parents.length; i++) {
File newDir = new File(parents[i], dirName);
createEmptyDirs(new String[] {newDir.toString()});
LocalFileSystem localFS = FileSystem.getLocal(new Configuration());
switch (nodeType) {
case NAME_NODE:
localFS.copyToLocalFile(
new Path(namenodeStorage.toString(), "current"), new Path(newDir.toString()), false);
Path newImgDir = new Path(newDir.getParent(), "image");
if (!localFS.exists(newImgDir))
localFS.copyToLocalFile(
new Path(namenodeStorage.toString(), "image"), newImgDir, false);
break;
case DATA_NODE:
localFS.copyToLocalFile(
new Path(datanodeStorage.toString(), "current"), new Path(newDir.toString()), false);
Path newStorageFile = new Path(newDir.getParent(), "storage");
if (!localFS.exists(newStorageFile))
localFS.copyToLocalFile(
new Path(datanodeStorage.toString(), "storage"), newStorageFile, false);
break;
}
retVal[i] = newDir;
}
return retVal;
}
