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Chapter 1. Introduction

Security is an important concern and should be a strong focus of any deployment. Data breaches and downtime are costly and difficult to manage, laws might require passing audits and compliance processes, and projects can expect a certain level of privacy and security for their data. This section provides a general introduction to security in Red Hat OpenStack Platform, as well as the role of Red Hat in supporting your system’s security.


This document provides advice and good practice information for hardening the security of your Red Hat OpenStack Platform deployment, with a focus on director-based deployments. While following the instructions in this guide will help harden the security of your environment, we do not guarantee security or compliance from following these recommendations.

1.1. Basic OpenStack Concepts

1.1.1. What is OpenStack?

To understand what OpenStack is, it is necessary to first understand what a cloud is. The simple version is that cloud computing is about making processing power, disk storage, database processing, and networking services available for consumption, allowing customers to interact with them programmatically through a set of APIs.

Compare this approach with a traditional hypervisor product that is focused on hosting virtual machines (VM): the VMs are used in the same way as traditional physical standalone servers, where one sysadmin will provision the virtual machine, and maybe a different sysadmin logs in and installs the database application, or other software. The VM then runs for a few years, stores the data locally on (or an attached SAN), and is backed up every day.

It is correct that OpenStack also operates virtual machines, but the management approach differs greatly from that described above. Instances should be ready to use once they are created, with the application ready, and no further configuration needed. If an issue is encountered, you should deploy a new replacement instance, rather than spending time troubleshooting the failures.

OpenStack has a whole selection of services that work together to accomplish what’s been described above, but that is only one of the many use cases.

For more information, see the OpenStack Product Guide:

1.1.2. Key terms

Before proceeding to the rest of this guide, it is recommended you become familiar with some of the OpenStack-specific terminology that a new user would encounter early on.

  • instance: This is a virtual machine. These are hosted on a dedicated hypervisor server, called a Compute node.
  • project: A partitioned collection of OpenStack resources, combining users, instances, and virtual networks (among others). Projects allow you to keep one collection of users and instances separate from another collection. This is useful for OpenStack deployments that host multiple different departments or organizations. An administrator must specify a destination project for each user or instance they create.
  • image: An operating system template. When you create an instance, you will need to decide which operating system it will run. OpenStack allows you to choose an operating system template, called an image. Pre-built images are available for CentOS and Red Hat Enterprise Linux.
  • flavor: A virtual machine hardware template. Rather than having to specify how much RAM and CPU to allocate each time you build an instance, you can define a flavor to pre-configure these values. Your Red Hat OpenStack Platform deployment will already have flavors defined, from m1.tiny with 1GB RAM, through to the m1.xlarge with 16GB.
  • security group: These are firewall rules. Each project can have its own security group, defining the traffic that is allowed to enter or leave the network.

1.1.3. Configuration Management with the Director

The Red Hat OpenStack Platform director lets you deploy and manage an OpenStack environment using YAML templates. This allows you to easily get a view of how your settings have been configured. The OpenStack configuration files are managed by Puppet, so any unmanaged changes are overwritten whenever you run the openstack overcloud deploy process. This allows you to have some assurance that your YAML configuration represents reality at a particular point in time. This approach also allows you to have a consistent, auditable, and repeatable approach to security configuration management in your OpenStack deployment. For disaster recovery, director’s use of configuration management and orchestration also improves the recovery time, as the cloud deployment and configuration is codified.

In addition, you can add your own customizations using a custom environment file that gets passed through at deployment time.

For more information, see the Director guide:

1.2. Security Boundaries and Threats

To understand the security risks that present themselves to your cloud deployment, it can be helpful to abstractly think about it as a collection of components that have a common function, users, and shared security concerns, which this guide refers to as security zones. Threat actors and vectors are classified based on their motivation and access to resources. The intention is to provide you a sense of the security concerns for each zone, depending on your objectives.

1.2.1. Security Zones

A security zone comprises users, applications, servers or networks that share common trust requirements and expectations within a system. Typically they share the same authentication and authorization requirements and users. Although you might refine these zone definitions further, this guide refers to the following distinct security zones which form the bare minimum that is required to deploy a security-hardened OpenStack cloud. These security zones are listed below from least to most trusted:

  • Public zone - External public-facing APIs, neutron external networks (Floating IP and SNAT for instance external connectivity).
  • Guest zone - Project networks (VLAN or VXLAN).
  • Storage access zone - Storage Management (storage monitoring and clustering), Storage (SAN/object/block storage).
  • Management zone - Typically includes the undercloud, host operating system, hardware, and networking, Undercloud control plane (provisioning/management of overcloud hosts), overcloud sysadmin/monitoring/backup
  • Admin zone - Allows endpoint access through the overcloud, Internal APIs, including infrastructure APIs, DB, RPC (will vary depending on the different API access roles for projects on the overcloud). Admin access to the overcloud should not require management access to the undercloud and hardware.

These security zones can be mapped separately, or combined to represent the majority of the possible areas of trust within a given OpenStack deployment. For example, some deployment topologies might consist of a combination of zones on one physical network while other topologies have these zones separated. In each case, you should be aware of the appropriate security concerns. Security zones should be mapped out against your specific OpenStack deployment topology. The zones and their trust requirements will vary depending upon whether the cloud instance is public, private, or hybrid. Public zone

The public security zone is an entirely untrusted area of the cloud infrastructure. It can refer to the Internet as a whole or simply to networks that are external to your Red Hat OpenStack Platform deployment which you have no authority. Any data with confidentiality or integrity requirements that traverses this zone should be protected using compensating controls.


Always consider this zone to be untrusted. Guest zone

Typically used for Compute instance-to-instance traffic, the guest security zone handles compute data generated by instances on the cloud, but not services that support the operation of the cloud, such as API calls.

Public and private cloud providers that do not have stringent controls on instance use or allow unrestricted internet access to instances should consider this zone to be untrusted. Private cloud providers might want to consider this network as internal and trusted only if the proper controls are implemented to assert that the instances and all associated projects (including the underlying hardware and internal networks) can be trusted. Storage access zone

Most of the data transmitted across this network requires high levels of integrity and confidentiality. In some cases, depending on the type of deployment there might also be strong availability requirements.

The storage access network should not be accessible outside of the deployment unless absolutely required. With the exception replication requirements, this network is assumed to not be accessible from outside the cloud, other than by storage appliances, and components deployed into this zone should be treated as sensitive from a security perspective.

The trust level of this network is heavily dependent on deployment decisions, therefore this guide does not assign a default level of trust to this zone. Control Plane

The control plane is where services interact. The networks in this zone transport confidential data such as configuration parameters, usernames, and passwords. Command and Control traffic typically resides in this zone, which necessitates strong integrity requirements. Access to this zone should be highly restricted and monitored. At the same time, this zone should still employ all of the security good practices described in this guide.

In most deployments this zone is considered trusted. However, when considering an OpenStack deployment, there are many systems that bridge this zone with others, potentially reducing the level of trust you can place on this zone. Management network

The management network is used for system administration, monitoring, and/or backup, but is a place where no OpenStack APIs or control interfaces are hosted. This location is where you would place the PXE network used for an on-premises and/or private Red Hat OpenStack Platform deployment, including any hardware management interfaces, network equipment and underlying operating system access for the director and compute/storage/management nodes.

1.3. Connecting security zones

Any component that spans across multiple security zones with different trust levels or authentication requirements must be carefully configured. These connections are often the weak points in network architecture, and should always be configured to meet the security requirements of the highest trust level of any of the zones being connected. In many cases the security controls the connected zones should be a primary concern due to the likelihood of attack. The points where zones meet do present an additional attack service, and adds opportunities for attackers to migrate their attack to more sensitive parts of the deployment.

In some cases, OpenStack operators might want to consider securing the integration point at a higher standard than any of the zones in which it resides. Given the above example of an API endpoint, an adversary could potentially target the Public API endpoint from the public zone, leveraging this foothold in the hopes of compromising or gaining access to the internal or admin API within the management zone if these zones were not completely isolated.

The design of OpenStack is such that separation of security zones is difficult. Because core services will usually span at least two zones, special consideration must be given when applying security controls to them.

1.4. Threat classification, actors, and attack vectors

Most types of cloud deployment, public, private, or hybrid, are exposed to some form of attack. This section categorizes attackers and summarizes potential types of attacks in each security zone.

1.4.1. Threat actors

A threat actor is an abstract way to refer to a class of adversary that you might attempt to defend against. The more capable the actor, the more rigorous the security controls that are required for successful attack mitigation and prevention. Security is a matter of balancing convenience, defense, and cost, based on requirements. In some cases it will not be possible to secure a cloud deployment against all of the threat actors described here. When deploying an OpenStack cloud, you must decide where the balance lies for your deployment and usage.

As part of your risk assessment, you must also consider the type of data you store and any accessible resources, as this will also influence certain actors. However, even if your data is not appealing to threat actors, they could simply be attracted to your computing resources, for example, to participate in a botnet, or to run unauthorized cryptocurrency mining.

  • Nation-State Actors - This is the most capable adversary. Nation-state actors can bring tremendous resources against a target. They have capabilities beyond that of any other actor. It is very difficult to defend against these actors without incredibly stringent controls in place, both human and technical.
  • Serious Organized Crime - This class describes highly capable and financially driven groups of attackers. They are able to fund in-house exploit development and target research. In recent years the rise of organizations such as the Russian Business Network, a massive cyber-criminal enterprise, has demonstrated how cyber attacks have become a commodity. Industrial espionage falls within the serious organized crime group.
  • Highly Capable Groups - This refers to ‘Hacktivist’ type organizations who are not typically commercially funded but can pose a serious threat to service providers and cloud operators.
  • Motivated Individuals Acting alone - these attackers come in many guises, such as rogue or malicious employees, disaffected customers, or small-scale industrial espionage.
  • Script Kiddies - These attackers don’t target a specific organization, but run automated vulnerability scanning and exploitation. They are often only a nuisance, however compromise by one of these actors is a major risk to an organization’s reputation.

The following practices can help mitigate some of the risks identified above:

  • Security updates - You must consider the end-to-end security posture of your underlying physical infrastructure, including networking, storage, and server hardware. These systems will require their own security hardening practices. For your Red Hat OpenStack Platform deployment, you should have a plan to regularly test and deploy security updates.
  • Access management - When granting system access to individuals, you should apply the principle of least privilege, and only grant them the granular system privileges they actually need. You can help enforce this policy using the practice of AAA (access, authorization, and accounting). This approach can also help mitigate the risks of both malicious actors and typographical errors from system administrators.
  • Manage insiders - You can help mitigate the threat of malicious insiders by applying careful assignment of role-based access control (minimum required access), using encryption on internal interfaces, and using authentication/authorization security (such as centralized identity management). You can also consider additional non-technical options, such as separation of duties and irregular job role rotation. Outbound Attacks and Reputational Risk

Careful consideration should be given to potential outbound abuse from a cloud deployment. Cloud deployments tend to have lots of resources available; an attacker who has established a point of presence within the cloud, either through hacking or entitled access, such as rogue employee, can use these resources for malicious purposes. Clouds with Compute services make for ideal DDoS and brute force engines. The issue is especially pressing for public clouds as their users are largely unaccountable, and can quickly spin up numerous disposable instances for outbound attacks. Methods of prevention include egress security groups, traffic inspection, intrusion detection systems, customer education and awareness, and fraud and abuse mitigation strategies. For deployments accessible by or with access to public networks, such as the Internet, processes and infrastructure should be in place to ideally detect, and also address outbound abuse.

1.5. Supporting software

Underpinning the whole of the Red Hat solution stack is the secure software supply chain. A cornerstone of Red Hat’s security strategy, the goal of this strategically important set of practices and procedures is to deliver solutions that have security built-in upfront and supported over time. Specific steps which Red Hat take include:

  • Maintaining upstream relationships and community involvement to help focus on security from the start.
  • Selecting and configuring packages based on their security and performance track records.
  • Building binaries from associated source code (instead of simply accepting upstream builds).
  • Applying a suite of inspection and quality assurance tools to prevent an extensive array of potential security issues and regressions.
  • Digitally signing all released packages and distributing them through cryptographically authenticated distribution channels.
  • Providing a single, unified mechanism for distributing patches and updates. The Red Hat Enterprise Linux and KVM components which underlie OpenStack are also Common Criteria certified. This involves a third party auditor performing physical site visits, and interviewing staff about adhering to good practices, for example, about the supply chain or development.

In addition, Red Hat maintains a dedicated security team that analyzes threats and vulnerabilities against our products, and provides relevant advice and updates through the Customer Portal. This team determines which issues are important, as opposed to those that are mostly theoretical problems. The Red Hat Product Security team maintains expertise in, and makes extensive contributions to the upstream communities associated with our subscription products. A key part of the process, Red Hat Security Advisories, deliver proactive notification of security flaws affecting Red Hat solutions – along with patches that are frequently distributed on the same day the vulnerability is first published.

1.6. System Documentation

1.6.1. System Roles and Types

The two broadly defined types of nodes that generally make up an OpenStack installation are:

  • Infrastructure nodes - These run the cloud-related services, such as the OpenStack API providers (such as neutron), the message queuing service, storage management, monitoring, networking, and other services required to support the operation and provisioning of the cloud.
  • Compute, storage, or other resource nodes - Provide compute and storage capacity for instances running on your cloud.

1.6.2. System Inventory

Documentation should provide a general description of the OpenStack environment and cover all systems used (for example, production, development, or test). Documenting system components, networks, services, and software often provides the perspective needed to thoroughly cover and consider security concerns, attack vectors, and possible security zone bridging points. A system inventory might need to capture ephemeral resources such as virtual machines or virtual disk volumes that would otherwise be persistent resources in a traditional IT environment.

1.6.3. Hardware Inventory

Clouds without stringent compliance requirements for written documentation might benefit from having a Configuration Management Database (CMDB). CMDBs are normally used for hardware asset tracking and overall life-cycle management. By leveraging a CMDB, an organization can quickly identify cloud infrastructure hardware such as compute nodes, storage nodes, or network devices. A CMDB can assist in identifying assets that exist on the network which might have vulnerabilities due to inadequate maintenance, inadequate protection, or being displaced and forgotten. An OpenStack provisioning system can provide some basic CMDB functions if the underlying hardware supports the necessary auto-discovery features.

1.6.4. Software Inventory

As with hardware, all software components within the OpenStack deployment should be documented. Examples include:

  • System databases, such as MySQL or mongoDB
  • OpenStack software components, such as Identity or Compute
  • Supporting components, such as load-balancers, reverse proxies, DNS, or DHCP services An authoritative list of software components might be critical when assessing the impact of a compromise or vulnerability in a library, application or class of software.

1.6.5. Network Topology

A network topology should be provided with highlights specifically calling out the data flows and bridging points between the security zones. Network ingress and egress points should be identified along with any OpenStack logical system boundaries. Multiple diagrams might be needed to provide complete visual coverage of the system. A network topology document should include virtual networks created on behalf of projects by the system along with virtual machine instances and gateways created by OpenStack, as well as physical and overlay networks used to provide communication between nodes and external networks.

1.6.6. Services, Protocols, and Ports

Knowing information about organizational assets is typically a good practice. An assets table can assist with validating security requirements and help to maintain standard security components such as firewall configuration, service port conflicts, security remediation areas, and compliance. Additionally, the table can help identify the relationship between OpenStack components. The table might include:

  • Services, protocols, and ports being used in the OpenStack deployment.
  • An overview of all services running within the cloud infrastructure.

It is recommended that OpenStack deployments maintain a record of this information. For a list of ports required for a director deployment, see

The port configuration is also contained in the heat templates of each service. You can extract this information with the following command:

find -L /usr/share/openstack-tripleo-heat-templates/ -type f | while read f;do if `grep -q firewall_rules $f`;then echo -e "\n $f " ; grep firewall_rules "$f" -A10;fi; done