Installing HDFS on Fedora CoreOS Latest

In this tutorial, we will guide you through the process of installing HDFS, which is a distributed file system from Apache Hadoop project, on Fedora CoreOS latest version. We assume that you already have a running instance of Fedora CoreOS up and running.

Prerequisites

A running instance of Fedora CoreOS latest version
A user account with sudo privileges
A stable internet connection

Step 1: Install Java

Before installing HDFS, it is essential to ensure you have Java installed on your system.

Update the package cache by running the following command:
```
$ sudo dnf makecache
```
Install the OpenJDK package by running the following command:
```
$ sudo dnf install java-1.8.0-openjdk-headless
```
Verify that Java has been installed by running the following command:
```
$ java -version
```
If Java has been installed correctly, you should see the version information displayed on your screen.

Step 2: Download and Install HDFS

Open your web browser and navigate to the official Hadoop website. You can download the latest version of Hadoop by clicking the following link: https://hadoop.apache.org/releases.html.
Once the download is complete, switch to the directory where you have downloaded the Hadoop package. In this case, we assume that the package has been downloaded to your home directory.
```
$ cd ~
```
Extract the Hadoop package by running the following command:
```
$ tar xvf hadoop-3.3.1.tar.gz
```
Move the extracted Hadoop directory to the /opt directory:
```
$ sudo mv hadoop-3.3.1 /opt/hadoop
```
Before configuring HDFS, it is important to set the JAVA_HOME environment variable. Edit the /etc/environment file and add the following line at the end:
```
JAVA_HOME=/usr/lib/jvm/java-1.8.0/
```
Reload the shell settings by running the following command:
```
$ source /etc/environment
```

Step 3: Configure HDFS

Open the core-site.xml file located in the /opt/hadoop/etc/hadoop directory using your preferred text editor:
```
$ sudo vi /opt/hadoop/etc/hadoop/core-site.xml
```

Add the following configuration settings within the <configuration> tags:

<property>
  <name>fs.defaultFS</name>
  <value>hdfs://localhost:9000</value>
</property>

Save and exit the file.
Open the hdfs-site.xml file using the following command:
```
$ sudo vi /opt/hadoop/etc/hadoop/hdfs-site.xml
```

Add the following configuration settings within the <configuration> tags:

<property>
  <name>dfs.replication</name>
  <value>1</value>
</property>
<property>
  <name>dfs.namenode.name.dir</name>
  <value>/opt/data/hdfs/namenode</value>
</property>
<property>
  <name>dfs.datanode.data.dir</name>
  <value>/opt/data/hdfs/datanode</value>
<property>
  <name>dfs.secondary.http.address</name>
  <value>localhost:50090</value>
</property>

Save and exit the file.

Step 4: Format HDFS

Before starting HDFS, it is important to format the file system. Run the following command to format HDFS:
```
$ /opt/hadoop/bin/hdfs namenode -format
```
If formatting is successful, you will see the following message on your screen:
```
Storage directory /opt/data/hdfs/namenode has been successfully formatted.
```

Step 5: Start HDFS

To start HDFS, run the following command:
```
$ /opt/hadoop/sbin/start-dfs.sh
```

If HDFS starts successfully, you will see the following message on your screen:

Starting namenodes on [localhost]
localhost: starting namenode, logging to /opt/hadoop/logs/hadoop-<your-username>-namenode-<your-hostname>.log
localhost: starting datanode, logging to /opt/hadoop/logs/hadoop-<your-username>-datanode-<your-hostname>.log

Step 6: Verify HDFS

To verify that HDFS is running, navigate to the following URL using your web browser:
```
http://localhost:9870/
```
If HDFS is running successfully, you will see the Hadoop Web UI displayed on your screen.
To verify that the HDFS file system has been mounted correctly, run the following command:
```
$ /opt/hadoop/bin/hdfs dfs -ls /
```
If the HDFS file system has been mounted correctly, you will see a list of root directory contents displayed on your screen.

Conclusion

Congratulations! You have successfully installed and configured HDFS on your Fedora CoreOS instance. You can now begin storing and managing your data using HDFS.