RHEL Intensive - Services: AWS, Networking, FTP, Apache, Firewalls, SELinux, and Samba

🎯 New to RHEL or AWS? This guide covers essential services for system administration, including AWS integration, networking, FTP, Apache, Firewalld, SELinux, and Samba. Each section includes theory, commands, and beginner tips to help you confidently manage RHEL systems and cloud services.

Table of Contents

🌐 Introduction to AWS Services

Amazon Web Services (AWS) is a leading cloud platform offering over 250 services for computing, storage, networking, databases, AI, analytics, and more. It’s widely used for scalable, cost-effective infrastructure.

Creating a Free AWS Account

AWS offers a Free Tier for new users to explore services with limited usage for 12 months. Here’s how to create one:

1. Visit aws.amazon.com/free.
2. Click Create a Free Account.
3. Provide an email, password, and account name.
4. Enter contact and billing details (a valid credit/debit card is required for verification, but you won’t be charged unless you exceed Free Tier limits).
5. Verify your identity via phone or SMS.
6. Select the Basic Support Plan (free) and complete the setup.

Free Tier Highlights:

• EC2: 750 hours/month of t2.micro or t3.micro instances (Linux/Windows).
• S3: 5 GB standard storage, 20,000 GET requests.
• RDS: 750 hours/month of a db.t2.micro database.
• Lambda: 1 million free requests/month.

Tip: Monitor usage via the AWS Billing Dashboard to stay within Free Tier limits. For detailed setup, see AWS Free Tier Guide.

Global Infrastructure

AWS operates globally, ensuring low-latency and high-availability services:

• Regions: 33 active regions (e.g., us-east-1, eu-west-1) as of 2025.
• Availability Zones (AZs): Each region has 3+ isolated AZs for redundancy.
• Edge Locations: 600+ points for CloudFront (CDN) caching.

Theory: Choose a region close to your users for lower latency. AZs provide fault tolerance by isolating failures.

Core AWS Services

Beginner Tip: Start with EC2 for RHEL servers, S3 for storage, and IAM for security. Use AWS Management Console for a user-friendly interface.

Specialty Services

• RoboMaker: Simulate and train robotics applications.
• IoT Core: Connect IoT devices (e.g., smart sensors) to AWS.
• Ground Station: Communicate with satellites.
• Braket: Experiment with quantum computing.

Example: Use IoT Core to manage smart devices with RHEL as a gateway. Learn more at AWS IoT Core.

Compute Services

• EC2: Virtual servers for RHEL, customizable with CPU, RAM, and OS.
• Elastic Load Balancer (ELB): Distributes traffic across EC2 instances.
• CloudWatch: Monitors EC2 metrics (CPU, disk I/O).
• Auto Scaling: Adjusts EC2 capacity based on load.
• Elastic Beanstalk: Simplifies app deployment (e.g., Node.js on RHEL).
• Lightsail: Easy hosting for small RHEL apps (e.g., WordPress).
• Lambda: Run code without servers (e.g., automate RHEL tasks).
• Serverless Application Repository: Prebuilt Lambda functions.
• Outposts: Run AWS services on-premises.
• Snowball/Snowcone: Physical devices for data transfer in remote areas.

Example: Deploy a RHEL-based web server on EC2. See EC2 Getting Started.

Containers

• ECR: Store Docker images for RHEL apps.
• ECS: Run Docker containers on AWS.
• EKS: Kubernetes for container orchestration.
• Fargate: Serverless container management.
• App Runner: Deploy containers with minimal setup.

Tip: Use ECS with RHEL-based Docker images for scalable apps. Learn at AWS ECS.

Storage

• S3: Store files (e.g., RHEL backups, logs).
• Glacier: Low-cost archival storage.
• EBS: Fast block storage for EC2.
• EFS: Shared file system for multiple EC2 instances.

Example: Back up RHEL logs to S3. See S3 Getting Started.

Databases

• SimpleDB: Basic NoSQL database.
• DynamoDB: Scalable NoSQL for high-traffic apps.
• DocumentDB: MongoDB-compatible database.
• OpenSearch: Search engine for logs and analytics.
• RDS: Managed SQL (e.g., MySQL on RHEL).
• Aurora: High-performance SQL database.
• Neptune: Graph database for relationships.
• ElastiCache: In-memory cache (Redis/Memcached).
• TimeStream: Time-series data (e.g., IoT metrics).
• QLDB: Tamper-proof ledger database.

Tip: Use RDS for RHEL-hosted databases. See RDS Documentation.

Analytics & Big Data

• Redshift: Data warehouse for analytics.
• Lake Formation: Centralize data storage.
• Kinesis: Real-time data streaming.
• EMR: Big data processing with Hadoop/Spark.
• MSK: Managed Kafka for streaming.
• Glue: ETL for data integration.

Example: Analyze RHEL server logs with Athena. Learn at AWS Athena.

Machine Learning & AI

• Data Exchange: Access public datasets.
• SageMaker: Build and deploy ML models.
• Rekognition: Image/video analysis.
• Lex: Create chatbots.
• DeepRacer: Learn ML with racing simulations.

Example: Use Rekognition to analyze images stored in S3. See AWS Rekognition.

Security & Identity

• IAM: Control access to AWS resources.
• Cognito: Manage user authentication.

Tip: Secure RHEL EC2 instances with IAM roles. See IAM Best Practices.

Communication

• SNS: Send notifications (SMS, email).
• SES: Send bulk emails.

Example: Notify admins via SNS for RHEL server alerts. Learn at AWS SNS.

Developer Tools

• CloudFormation: Automate infrastructure setup.
• Amplify: Connect RHEL apps to AWS services.

Example: Use CloudFormation to deploy RHEL EC2 instances. See CloudFormation Guide.

Cost Management

• Cost Explorer: Analyze AWS spending.
• Budgets: Set cost alerts.

Tip: Use Budgets to monitor Free Tier usage. See AWS Cost Management.

EC2 Instance Families

EC2 instances are grouped by use case:

Tip: Use t4g.micro (ARM-based Graviton) for Free Tier RHEL instances. See EC2 Instance Types.

EBS Volume Types

EBS provides block storage for EC2:

Tip: Use gp3 for cost-effective performance. See EBS Volume Types.

S3 Storage Classes

S3 storage classes optimize cost and access speed:

Tip: Use Intelligent-Tiering for RHEL logs with varying access patterns. See S3 Storage Classes.

📡 Server-Client Model (NFS Setup)

Network File System (NFS) allows file sharing between RHEL servers and clients.

On Server

1. Set Hostname:

   sudo hostnamectl set-hostname server1.example.com
   cat /etc/hostname

2. Add DNS Entry: Edit /etc/hosts:

   sudo nano /etc/hosts

   Add:

   192.168.1.10  server1.example.com

3. Install NFS:

   sudo yum install nfs-utils -y

4. Start Services:

   sudo systemctl start rpcbind nfs-server
   sudo systemctl enable rpcbind nfs-server

5. Verify Ports (NFS uses 2049):

   sudo ss -tulpn | grep 2049

6. Create Share:

   sudo mkdir -p /server
   sudo chmod -R 755 /server

7. Configure Exports: Edit /etc/exports:

   sudo nano /etc/exports

   Add:

   /server 192.168.1.0/24(rw,sync,no_root_squash)

8. Export Share:

   sudo exportfs -rv

9. Firewall Rules:

   sudo firewall-cmd --permanent --add-service=nfs
   sudo firewall-cmd --reload

On Client

1. Check Exports:

   showmount -e server1.example.com

2. Mount Share:

   sudo mkdir -p /data
   sudo mount server1.example.com:/server /data

3. Persistent Mount: Edit /etc/fstab:

   server1.example.com:/server /data nfs defaults 0 0

Theory: NFS enables seamless file sharing in a server-client model, ideal for centralized storage.

Tip: Use firewalld instead of disabling the firewall. See NFS Documentation.

📂 FTP (File Transfer Protocol)

FTP transfers files between systems. vsftpd is the default FTP server in RHEL.

Installation

sudo yum install vsftpd -y

Start Service

sudo systemctl start vsftpd
sudo systemctl enable vsftpd

Firewall Rules

sudo firewall-cmd --permanent --add-service=ftp
sudo firewall-cmd --reload

Configure vsftpd

Edit /etc/vsftpd/vsftpd.conf:

anonymous_enable=NO
local_enable=YES
write_enable=YES
chroot_local_user=YES
allow_writeable_chroot=YES
pasv_enable=YES
pasv_min_port=30000
pasv_max_port=31000

Restart:

sudo systemctl restart vsftpd

Add FTP User

sudo adduser ftpuser
sudo passwd ftpuser
sudo mkdir -p /home/ftpuser/ftp_files
sudo chown ftpuser:ftpuser /home/ftpuser/ftp_files

Test Connection

ftp 192.168.1.10

SELinux Context

Set context for FTP directories:

sudo chcon -t public_content_t /home/ftpuser/ftp_files
sudo semanage fcontext -a -t public_content_t "/home/ftpuser/ftp_files(/.*)?"
sudo restorecon -Rv /home/ftpuser/ftp_files

Theory: FTP uses ports 21 (control) and 20 (data in active mode). SFTP (port 22) is more secure. See vsftpd Documentation.

Tip: Enable passive mode for firewall compatibility.

🌐 Apache HTTP Server

Apache serves web content and is widely used in RHEL.

Installation

sudo yum install httpd -y

Start Service

sudo systemctl start httpd
sudo systemctl enable httpd

Firewall Rules

sudo firewall-cmd --permanent --add-service=http
sudo firewall-cmd --permanent --add-service=https
sudo firewall-cmd --reload

Configure Virtual Host

Edit /etc/httpd/conf.d/site1.conf:

<VirtualHost *:80>
    ServerName site1.example.com
    DocumentRoot /var/www/site1
    <Directory /var/www/site1>
        Options Indexes FollowSymLinks
        AllowOverride All
        Require all granted
    </Directory>
    ErrorLog /var/log/httpd/site1_error.log
    CustomLog /var/log/httpd/site1_access.log combined
</VirtualHost>

Create directory:

sudo mkdir -p /var/www/site1
sudo echo "<h1>Hello from site1</h1>" > /var/www/site1/index.html
sudo chown -R apache:apache /var/www/site1

SELinux Context

sudo chcon -R -t httpd_sys_content_t /var/www/site1
sudo semanage fcontext -a -t httpd_sys_content_t "/var/www/site1(/.*)?"
sudo restorecon -Rv /var/www/site1

Test Config

sudo httpd -t
sudo systemctl restart httpd

Theory: Apache uses a modular architecture with virtual hosts for multiple websites. See Apache Documentation.

Tip: Use apachectl configtest to avoid downtime from config errors.

🔥 Firewalld

Firewalld is RHEL’s default firewall, using zones and services for dynamic management.

Key Commands

• List services:

  firewall-cmd --list-services

• Add service:

  firewall-cmd --permanent --add-service=http
  firewall-cmd --reload

• List zones:

  firewall-cmd --get-zones

• Set default zone:

  firewall-cmd --set-default-zone=block

Theory: Firewalld simplifies firewall management with predefined services (e.g., http, ftp). Zones allow context-based rules.

Tip: Always use --permanent to persist rules. See Firewalld Documentation.

🔒 SELinux

SELinux enforces mandatory access control in RHEL.

Check Status

getenforce
sestatus

Set Mode

Temporary:

setenforce 0  # Permissive
setenforce 1  # Enforcing

Permanent: Edit /etc/selinux/config:

SELINUX=enforcing

Manage Contexts

View file context:

ls -Z /var/www/html

Set context:

sudo chcon -t httpd_sys_content_t /var/www/html/index.html
sudo semanage fcontext -a -t httpd_sys_content_t "/var/www/html(/.*)?"
sudo restorecon -Rv /var/www/html

Booleans

List:

getsebool -a | grep httpd

Set:

setsebool -P httpd_enable_homedirs on

Logs

Check denials:

grep denied /var/log/audit/audit.log

Analyze:

sudo yum install policycoreutils-devel -y
audit2why < /var/log/audit/audit.log

Theory: SELinux uses contexts to enforce security policies, even for root. See Red Hat SELinux Guide.

Tip: Use permissive mode for troubleshooting, then re-enable enforcing.

📂 Samba

Samba enables file sharing between RHEL and Windows systems.

Installation

sudo yum install samba samba-client samba-common -y

Configure Share

Edit /etc/samba/smb.conf:

[global]
   workgroup = WORKGROUP
   server string = Samba Server %v
   netbios name = rhel-server
   security = user
   map to guest = bad user

[shared]
   path = /srv/samba/shared
   browsable = yes
   writable = yes
   guest ok = yes
   read only = no

Create directory:

sudo mkdir -p /srv/samba/shared
sudo chown -R nobody:nogroup /srv/samba/shared
sudo chmod -R 0775 /srv/samba/shared

SELinux Context

sudo chcon -t samba_share_t /srv/samba/shared
sudo semanage fcontext -a -t samba_share_t "/srv/samba/shared(/.*)?"
sudo restorecon -Rv /srv/samba/shared

Firewall Rules

sudo firewall-cmd --permanent --add-service=samba
sudo firewall-cmd --reload

Start Services

sudo systemctl start smbd nmbd
sudo systemctl enable smbd nmbd

Add Samba User

sudo adduser smbuser
sudo smbpasswd -a smbuser
sudo smbpasswd -e smbuser

Test Share

From Windows: \\<server-ip>\shared

From Linux:

smbclient //192.168.1.10/shared -U smbuser

Theory: Samba uses SMB/CIFS for cross-platform file sharing. See Samba Documentation.

Tip: Restrict access with valid users for security.

🧭 What’s Next?

You’re now ready to manage AWS services, NFS, FTP, Apache, Firewalld, SELinux, and Samba on RHEL! Practice in a Free Tier AWS account or a local VM. Explore advanced topics like Ansible for automation or AWS CloudFormation for infrastructure. Questions? Check Red Hat Documentation or AWS Training.