> For the complete documentation index, see [llms.txt](https://george-jen.gitbook.io/data-science-and-apache-spark/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://george-jen.gitbook.io/data-science-and-apache-spark/hadoop-configuration.md).

# Hadoop Preparation

We need to add a new host name in /etc/hosts, called hadoop.master.lan, in my case:

cat /etc/hosts

…

10.0.0.46 master.hadoop.lan

You need to specify your IP address, not copy 10.0.0.46 in this slide. Run “ifconfig” to find out the IP address of your host.

Now, configure ssh key based authentication for hadoop account by running the below commands (replace the hostname or FQDN against the ssh-copy-id command accordingly).

Also, leave the passphrase filed blank in order to automatically login via ssh.

$ ssh-keygen -t rsa

$ ssh-copy-id master.hadoop.lan

You will see something similar to below:

![](/files/-M1dafAIH3pcOewihpR0)

You can test

ssh master.hadoop.lan

You should be able to log in by ssh without password


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://george-jen.gitbook.io/data-science-and-apache-spark/hadoop-configuration.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.