Christian WellsDocker Engine on Rocky Linux 9 – Reliable Containerization on an Enterprise-Grade Linux Platform
Docker Engine is the industry-standard container runtime for building, running, and managing containerized applications. When paired with Rocky Linux 9, a RHEL-compatible, community-maintained enterprise Linux distribution, it forms a stable, secure, and efficient foundation for both development and production container workloads.
Why Use Rocky Linux 9 for Docker?
Rocky Linux 9 is a direct, binary-compatible downstream of Red Hat Enterprise Linux 9. It provides the same level of system stability and enterprise features as RHEL, making it highly suitable for running Docker Engine in environments where long-term support and consistent behavior are critical.
Key benefits of using Docker on Rocky Linux 9:
- Full compatibility with RHEL packages and security policies
- Long-term support lifecycle, ideal for production deployments
- Integrated SELinux enforcement for container isolation
- Systemd-based service management for robust daemon control
- OverlayFS and cgroups v2 support out of the box
Docker Engine Components
Docker Engine consists of:
dockerd– the background service managing containersdockerCLI – the command-line interface to interact with containers, images, and volumescontainerd– the OCI-compliant runtime delegated to by Dockerrunc– the low-level container runtime
Docker provides a full container lifecycle management system and integrates with orchestration tools, registries, CI/CD pipelines, and monitoring platforms.
System Integration with Rocky Linux 9
| System Component | Docker Compatibility |
|---|---|
| Linux Kernel 5.14 | Supports OverlayFS, cgroup v2, namespaces, and seccomp |
| Systemd 250+ | Native service control for Docker (systemctl start docker) |
| SELinux | Enforcing mode enabled by default; Docker provides SELinux profiles |
| FirewallD | Manages NAT and forwarding for container networking |
| dnf & EPEL | Provides packages for Docker, container tools, and dependencies |
Rocky Linux offers a consistent, RHEL-aligned foundation for container workloads, with hardened security defaults and robust logging capabilities.
Use Cases for Docker on Rocky Linux 9
- Hosting modern microservices using containers and Compose
- Packaging monolithic applications into isolated environments
- Building development and test environments with reproducible containers
- Creating CI/CD pipelines with tools like Jenkins, GitLab CI, or Drone
- Running self-hosted applications such as databases, message queues, and monitoring tools
- Deploying containerized apps across hybrid and multi-cloud infrastructure
Rocky Linux’s predictable system behavior is particularly useful in regulated and enterprise-grade environments.
Performance and Resource Control
| Feature | Benefit in Docker Environments |
|---|---|
| Cgroups v2 | Enables precise allocation of CPU, memory, and I/O per container |
| Namespaces | Provides isolation for process IDs, users, networks, and mounts |
| OverlayFS v2 | Reduces image size and improves filesystem performance |
| Seccomp | Filters potentially unsafe syscalls used inside containers |
| Rootless Docker | Optional configuration for non-privileged container execution |
These features are fully supported in Rocky Linux 9, allowing Docker to perform efficiently and securely across a variety of deployment models.
Docker vs Podman on Rocky Linux 9
| Aspect | Docker Engine | Podman |
|---|---|---|
| Daemon model | Requires background daemon (dockerd) | Daemonless; CLI spawns containers directly |
| CLI compatibility | Full Docker CLI | Mostly Docker-compatible CLI |
| Compose support | Native (docker compose) | Supported via Podman Compose |
| Rootless containers | Supported with setup | Native and enabled by default |
| Kubernetes integration | Via containerd | Compatible through CRI-O |
While Docker remains the most widely adopted container runtime for developers and CI/CD tools, Podman is often chosen for server environments with stricter security or no-daemon policies.
Security Considerations
Rocky Linux 9 provides several features that enhance Docker’s security:
- SELinux in enforcing mode helps restrict container behavior at the kernel level
- FirewallD and nftables help isolate container networks
- Auditd tracks container system activity
- Systemd integrates with
journaldfor centralized logging - Rootless Docker support allows users to run containers without elevated privileges
Administrators can further harden the system by customizing SELinux policies or isolating Docker with AppArmor or external firewalls.
Rocky Linux 9 as a Base Image for Containers
Rocky Linux also provides official container images such as rockylinux:9, which are useful for:
- Building enterprise-grade RPM-based application containers
- Maintaining consistency across development and production environments
- Using trusted and signed container layers for security-sensitive applications
These images are minimal and well-maintained, making them suitable for both general-purpose and specialized container builds.
Docker Engine on Rocky Linux 9 delivers a high-performance, enterprise-ready container environment built on a stable, RHEL-compatible operating system. With a strong focus on compatibility, security, and long-term viability, this combination is ideal for organizations that require reliability and support across their container infrastructure.
Rocky Linux 9 offers the same robustness as RHEL without vendor lock-in, making it a compelling choice for deploying Docker containers in production environments, development stacks, and hybrid cloud platforms.
Step 1: Set Up a Server Instance on Shape.Host
To begin, you’ll need a clean Rocky Linux 9 VPS. Shape.Host offers fast, scalable cloud VPS solutions that are perfect for Docker-based projects.
Follow these steps to create your server:
Go to https://shape.host and sign in.
Click on “Create” in the top menu.
Choose “Instance” from the options available.
Select your preferred data center (e.g., Frankfurt, Dallas).
For the operating system, select Rocky Linux 9 (64-bit).
Pick a hosting plan with at least 2 CPUs, 2 GB RAM, and 20 GB SSD.
Click “Create Instance” to launch your server.
Once it’s ready, find your instance’s IP address in the Resources section.
How to Connect to Your Instance
Use SSH to connect once the server is ready.
On Linux/macOS:
Open your terminal and run:
ssh root@your_server_ip
Replace your_server_ip with your actual server IP.
On Windows:
Use PuTTY:
- Download PuTTY from https://www.putty.org.
- Open PuTTY and paste your instance IP into the Host Name field.
- Use port
22and select SSH. - Click Open and log in with the username
root.
Step 2: Install Docker Engine on Rocky Linux 9
Below are the exact commands to install Docker Engine, split for clarity and with all intended comments included.
1. Update your system packages:
dnf update
2. Install necessary tools and dependencies:
dnf install yum-utils curl ca-certificates gnupg lsb-release
3. Create the yum repository directory:
mkdir -p /etc/yum.repos.d
4. Add the Docker repository:
tee /etc/yum.repos.d/docker-ce.repo > /dev/null <<EOF
[docker-ce-stable]
name=Docker CE Stable - \$basearch
baseurl=https://download.docker.com/linux/centos/9/\$basearch/stable
enabled=1
gpgcheck=1
gpgkey=https://download.docker.com/linux/centos/gpg
EOF
5. Install Docker Engine and its components:
dnf install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin
6. Start the Docker service:
systemctl start docker
7. Enable Docker to start automatically on boot:
systemctl enable docker
8. Check the status of the Docker service:
systemctl status docker
Step 3: Verify Docker Installation
To ensure Docker is working correctly, run the hello-world container:
docker run hello-world
You should see a success message confirming that Docker Engine is installed and running properly.
Optional Step: Uninstall Docker (if needed)
If you ever need to remove Docker, use the following commands:
1. Remove Docker and its related components:
dnf remove docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin
2. Delete Docker-related data:
rm -rf /var/lib/docker
rm -rf /var/lib/containerd
You have successfully installed Docker Engine on Rocky Linux 9. This setup allows you to create and manage containers for development and production environments effortlessly. For fast, scalable, and reliable cloud hosting, choose Shape.Host Cloud VPS—perfect for running Docker and other modern DevOps tools.
Visit https://shape.host to launch your own cloud server today.
