Set hadoop system user for client embedded in Java webapp

Finally I stumbled on the constant

static final String HADOOP_USER_NAME = "HADOOP_USER_NAME";`

in the UserGroupInformation class.

Setting this either as an environment variable, as a Java system property on startup (using -D) or programmatically with System.setProperty("HADOOP_USER_NAME", "hduser"); makes Hadoop use whatever username you want for connecting to the remote Hadoop cluster.

The code below works for me the same as

System.setProperty("HADOOP_USER_NAME", "hduser")

UserGroupInformation ugi = UserGroupInformation.createRemoteUser("hduser"); ugi.doAs(new PrivilegedExceptionAction<Void>() {    public Void run() throws Exception {        Configuration configuration = new Configuration();         configuration.set("hadoop.job.ugi", "hduser");        int res = ToolRunner.run(configuration, new YourTool(), args);        return null;     }});

I am able to resolve similar issue by using secure impersonation feature http://hadoop.apache.org/docs/stable1/Secure_Impersonation.html

following is code snippet

    UserGroupInformation ugi = UserGroupInformation.createProxyUser("hduser", UserGroupInformation.getLoginUser());     ugi.doAs(new PrivilegedExceptionAction() {     public Void run() throws Exception {       Configuration jobconf = new Configuration();       jobconf.set("fs.default.name", "hdfs://server:hdfsport");       jobconf.set("hadoop.job.ugi", "hduser");       jobconf.set("mapred.job.tracker", "server:jobtracker port");       String[] args = new String[] { "data/input", "data/output" };       ToolRunner.run(jobconf, WordCount.class.newInstance(), args);       return null;     } });

The remote (windows desktop host in my case) login user id should be added in core-site.xml as mentioned in above mentioned URL