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Security and Your OpenMetal Private Cloud


This article provides further information for the security best practices for your OpenMetal Cloud. Although OpenStack is a security-focused architecture, it is important to follow the concepts of least privilege as well as perform regular maintenance updates to prevent security vulnerabilities from emerging. This article details how users and groups can be leveraged to segment your network and improve security through reduced privileges. Finally, additional documentation is provided for the OpenStack Security Center for analysis on current threats.

Principle of Least Privilege

The philosophy around the principle of least privilege is a user account should only have privileges necessary to perform its intended function. For example, a financial analyst does not require admin rights or a software engineer should not need to access financial records.

The benefits of operating a system using the principle of least privilege are:

  • System stability - Limiting the scope of changes reduces adverse effects of applications running on your system. This means that programs are less likely to perform actions that could crash your machine.
  • System security - Limiting the system-wide changes can reduce blast radius. The blast radius is the maximum amount of damage an intruder can inflict after gaining access to your system.
  • Ease of deployment - As a general rule, the fewer privileges an application needs to run, the easier it is to deploy to a larger environment.

When implementing the principles of least privilege, routine audits are important to maintain the security of your system and avoid privilege creep. Privilege creep is when a user or program is given more access or rights beyond what is necessary to their job. In addition to conducting regular audits, consider starting all user and system accounts with the least privilege and enforcing the separation of privileges.

Users, Groups, Projects, and Roles

Within OpenStack, there is the ability to set individual access controls. These controls have different levels of granularity from setting a project and allocating resources to managing groups of individuals. There is even the ability to manage down to an individual user.

For information about how to create a user and project, see Create an OpenStack User and Project in Horizon.


When working in OpenStack, there is only one administrative user. Using the principle of least privilege, you should create additional users when handling various tasks within your private cloud environment.


Groups are a collection of Users within OpenStack. Groups allow an administrator to manage permissions for several individual users at the same time. This method for managing access helps to avoid privilege creep as individuals can be removed from groups as their roles change within an organization.


Projects allow you to allocate resources within your private cloud. You can isolate users and individual projects to further control access to cloud resources.


Keystone roles are rights and privileges given to a user to perform tasks. Each service can require different types of roles to perform different actions. In addition, existing roles can be modified through the services policy.json file. Due to the containerization of OpenStack services these policy files will be found within the docker container of the service in /etc/service_name/policy.json. To find out more information about creating and managing roles visit Create and manage roles.

Updating Software

All software running your Private Cloud is open source. Maintaining up-to-date software is important for the security of your private cloud. Among the major areas that require updating are individual instances, images, and the control plane nodes. Both operating system packages and applications require software updates over time as changes are made.

Update Individual Instances

For any instances your cloud contains, ensure the software within is kept up to date. This includes the operating system's software and the applications running within the instance. This software is typically managed through a package manager like apt or dnf.

Updating the software in individual instances can be accomplished by connecting to the instance through SSH. Once inside the instance, updates can be run using the package manager of the Linux distribution and rebooting.

Update Glance Images

Glance is the service in OpenStack responsible for managing operating system images. Once your private cloud is deployed, these images are not updated. Over time, these images can become vulnerable as it becomes necessary to maintain security updates and patches. We recommend routinely updating and managing these images within your existing OpenStack cluster. For further information on how to upload images visit Manage and Upload Images in Horizon

Update Kolla Ansible Images

Kolla Ansible relies on Docker images to deploy the various OpenStack containers. Over time, updates occur, causing existing images to be out of date. As part of regular cloud maintenance, these images can be updated, using Kolla Ansible. To learn more, see How to Obtain Latest OpenStack Images using Kolla Ansible.

Update Control-Plane Nodes

For each hardware node, your cloud has, operating system updates should be performed as part of routine maintenance. These updates are best handled by the operating system's package manager, which for Private Clouds running CentOS 8, is dnf. For more information on how to update control plane nodes visit OpenStack Hardware Node Maintenance.

Enabling TLS

TLS stands for Transport Layer Security protocol and is the successor to the SSL. Both TLS and SSL work in much the same way, using encryption to protect the transfer of information and data between two systems. Within OpenMetal, enabling TLS is very important for protecting login credentials for your Horizon Dashboard.

For more information on how to enable TLS within Horizon, visit How to Enable TLS for OpenStack using Kolla Ansible.

Security Groups

In your private cloud, security groups act as a firewall to control inbound and outbound traffic to your instances. OpenStack has many different configurations for security groups that allow you to control the type of traffic to your instance as well as the port. The configuration options are known as rules. Rules define the types of ports that are available on your instance as well as the IP addresses that can connect to these specific ports.

For more information on how to create and manage security groups, see the title heading Security Groups in the How to Create an Instance in OpenStack Horizon guide.

SSH Authentication

Authentication in your private cloud is handled by SSH keys. These keys are injected into your control plane nodes from the moment of deployment of your cloud. Authentication keys can also be added to instances before being deployed. For additional security, consider restricting access to port 22 and limiting SSH access to control plane nodes.

OpenStack Security Advisor and Further Resources

OpenStack uses two different means for communicating security-related information: Advisories and Notes. OpenStack Security Advisories (OSSA) help to communicate fixes to severe security issues. OpenStack Security Notes (OSSN) provide general notices for potential vulnerabilities in design, deployment, and configuration. OpenStack does have a Vulnerability Management Team (VMT) for further information on how to contact visit OpenStack Security.

A list of current Security Advisories for OpenStack can be found Here.

For a more in-depth look into current best practices with OpenStack see OpenStack Security Guide.