What Operating Systems Do You Support?

Introduction

InMotion Cloud OpenStack provides a selection of pre-configured operating system images for deploying instances (virtual machines). These images come with cloud-init pre-installed, enabling automatic configuration during instance launch, including SSH key injection and network setup.

This guide covers the available operating system images, their default configurations, and how to choose the right distribution for your workload.

Available Operating System Images

InMotion Cloud maintains several production-ready Linux distribution images. All images include cloud-init for automated provisioning and are optimized for cloud workloads.

Ubuntu

Ubuntu is a popular Debian-based distribution known for its ease of use, extensive documentation, and strong community support.

Available versions:

• Ubuntu 22.04 LTS (Jammy Jellyfish)
• Ubuntu 24.04 LTS (Noble Numbat)

Default SSH username: ubuntu

Best for:

• Web applications and development environments
• Containerized workloads with Docker or Kubernetes
• Users new to Linux server administration
• Environments requiring extensive third-party software support

AlmaLinux

AlmaLinux is an enterprise-grade Linux distribution that serves as a drop-in replacement for CentOS. It is binary-compatible with Red Hat Enterprise Linux (RHEL) and receives long-term support.

Available versions:

• AlmaLinux 8
• AlmaLinux 9

Default SSH username: almalinux

Best for:

• Enterprise applications requiring RHEL compatibility
• Production workloads needing long-term stability
• Organizations migrating from CentOS
• Applications certified for RHEL environments

Rocky Linux

Rocky Linux is a community-driven enterprise operating system designed to be 100% bug-for-bug compatible with RHEL. It was created by CentOS co-founder Gregory Kurtzer.

Available versions:

• Rocky Linux 8
• Rocky Linux 9

Default SSH username: rocky

Best for:

• Enterprise workloads requiring RHEL compatibility
• Environments previously running CentOS
• Applications requiring SELinux security policies
• Production systems needing predictable release cycles

Debian

Debian is one of the oldest and most stable Linux distributions. It prioritizes stability and security, making it an excellent choice for servers that require minimal maintenance.

Available versions:

• Debian 11 (Bullseye)
• Debian 12 (Bookworm)

Default SSH username: debian

Best for:

• Long-running production servers
• Security-focused deployments
• Minimalist server configurations
• Users preferring stable over cutting-edge packages

Fedora

Fedora is a cutting-edge Linux distribution sponsored by Red Hat. It features the latest software packages and serves as a testing ground for technologies that eventually appear in RHEL.

Available versions:

• Fedora Cloud (latest release)

Default SSH username: fedora

Best for:

• Development and testing environments
• Evaluating upcoming RHEL features
• Workloads requiring the latest kernel and software versions
• Users who want newer packages than LTS distributions provide

Viewing Available Images in Horizon

To view the operating system images available in your project:

1. Log in to the OpenStack Horizon dashboard
2. Navigate to Project > Compute > Images
3. The Images panel displays all available images
4. Filter by visibility to see Public images (provided by InMotion Cloud) or Private images (uploaded by your organization)

Each image listing shows:

• Name: The image name and version
• Type: Image format (typically QCOW2)
• Status: Active images are ready for use
• Visibility: Public (shared), Private (project-specific), or Community
• Size: Disk space required for the image

Viewing Available Images Using OpenStack CLI

List all available images with the openstack command-line client:

1openstack image list
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Example output:

1+--------------------------------------+----------------------+--------+
2| ID                                   | Name                 | Status |
3+--------------------------------------+----------------------+--------+
4| a1b2c3d4-1234-5678-abcd-ef1234567890 | Ubuntu 22.04 LTS     | active |
5| b2c3d4e5-2345-6789-bcde-fg2345678901 | Ubuntu 24.04 LTS     | active |
6| c3d4e5f6-3456-7890-cdef-gh3456789012 | AlmaLinux 9          | active |
7| d4e5f6g7-4567-8901-defg-hi4567890123 | Rocky Linux 9        | active |
8| e5f6g7h8-5678-9012-efgh-ij5678901234 | Debian 12            | active |
9+--------------------------------------+----------------------+--------+
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To view detailed information about a specific image:

1openstack image show "Ubuntu 22.04 LTS"
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This displays the image properties, including minimum disk and RAM requirements, architecture, and creation date.

To filter images by visibility:

1openstack image list --public
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Default SSH Usernames by Distribution

When connecting to a newly launched instance, use the default username for the operating system image:

Connection example:

1ssh -i /path/to/private-key.pem ubuntu@instance-ip
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Replace ubuntu with the appropriate username for your distribution.

Minimum Instance Requirements

Each operating system image has minimum resource requirements. These are general guidelines; production workloads typically require more resources.

When creating boot volumes, allocate at least the minimum disk size specified for the image. Boot volume creation will fail if the volume size is smaller than the image requires.

Choosing an Operating System

Consider the following factors when selecting an operating system:

Application Compatibility

• RHEL-compatible applications: Choose AlmaLinux or Rocky Linux
• Ubuntu-specific packages: Choose Ubuntu
• Stability over features: Choose Debian
• Latest software versions: Choose Fedora or Ubuntu non-LTS

Support Lifecycle

Long-term support (LTS) releases receive security updates for extended periods:

• Ubuntu LTS: 5 years of standard support
• AlmaLinux: 10 years of support
• Rocky Linux: 10 years of support
• Debian: Approximately 5 years (3 years full + 2 years LTS)

For production workloads, LTS releases minimize the frequency of major version upgrades.

Package Management

• APT-based (Ubuntu, Debian): apt update && apt upgrade
• DNF-based (AlmaLinux, Rocky, Fedora): dnf update

Choose a distribution whose package manager your team is comfortable with.

Security Features

• SELinux is enabled by default on AlmaLinux, Rocky Linux, and Fedora
• AppArmor is enabled by default on Ubuntu and Debian

Both provide mandatory access control; choose based on your organization's security policies and expertise.

Custom Images

In addition to the provided public images, you can upload custom images to use with your instances.

Supported Image Formats

OpenStack Glance supports multiple image formats:

• QCOW2: Recommended format, supports copy-on-write and snapshots
• RAW: Uncompressed disk image
• VHD/VHDX: Microsoft Hyper-V format
• VMDK: VMware format
• ISO: Bootable installation media

Custom Image Requirements

For an image to work properly in OpenStack, it should:

1. Include cloud-init: Enables automatic configuration and SSH key injection
2. Use virtio drivers: Provides optimal performance for disk and network I/O
3. Have DHCP enabled: Allows automatic network configuration
4. Disable root password: Use SSH keys for authentication

Uploading a Custom Image in Horizon

1. Navigate to Project > Compute > Images
2. Click Create Image
3. Enter the image name and description
4. Select the image source (file upload or URL)
5. Choose the image format
6. Set minimum disk and RAM requirements
7. Click Create Image

Uploading a Custom Image Using CLI

1openstack image create \
2  --file /path/to/image.qcow2 \
3  --disk-format qcow2 \
4  --container-format bare \
5  --min-disk 10 \
6  --min-ram 1024 \
7  --property os_distro=ubuntu \
8  "My Custom Ubuntu Image"
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Windows Operating Systems

InMotion Cloud OpenStack is a Linux-based cloud platform. Windows Server images are not provided in the public image library.

If your workload requires Windows Server, consider the following options:

1. Upload a custom Windows image: You can create and upload your own Windows Server image with appropriate licensing
2. Use a Linux alternative: Many Windows workloads can be migrated to Linux equivalents
3. Contact support: Discuss Windows hosting requirements with the InMotion Cloud team

Custom Windows images must include the VirtIO drivers for proper disk and network functionality in OpenStack.

Related Resources

• OpenStack Virtual Machine Image Guide
• Ubuntu Cloud Images
• AlmaLinux Cloud Images
• Rocky Linux Cloud Images
• Debian Cloud Images