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Chapter 7. Hardening Infrastructure and Virtualization

Check with hardware and software vendors periodically to get available information about new vulnerabilities and security updates. Red Hat Product Security maintains the following sites to inform you of security updates:

Keep the following in mind as you regularly update your deployment of Red Hat OpenStack Platform.

  • Ensure all security updates are included.
  • Kernel updates require a reboot.
  • Update hosted Image service (glance) images to ensure that newly created instances have the latest updates.

7.1. Hypervisors

When you evaluate a hypervisor platform, consider the supportability of the hardware on which the hypervisor will run. Additionally, consider the additional features available in the hardware and how those features are supported by the hypervisor you chose as part of the OpenStack deployment. To that end, hypervisors each have their own hardware compatibility lists (HCLs). When selecting compatible hardware it is important to know in advance which hardware-based virtualization technologies are important from a security perspective.

7.1.1. Hypervisor versus bare metal

It is important to recognize the difference between using Linux containers or bare metal systems versus using a hypervisor like KVM. Specifically, the focus of this security guide is largely based on having a hypervisor and virtualization platform. However, should your implementation require the use of a bare metal or containerized environment, you must pay attention to the particular differences in regard to deployment of that environment.

For bare metal, make sure the node has been properly sanitized of data prior to re-provisioning and decommissioning. In addition, before reusing a node, you must provide assurances that the hardware has not been tampered or otherwise compromised. For more information see

7.1.2. Hypervisor memory optimization

Certain hypervisors use memory optimization techniques that overcommit memory to guest virtual machines. This is a useful feature that allows you to deploy very dense compute clusters. One approach to this technique is through deduplication or sharing of memory pages: When two virtual machines have identical data in memory, there are advantages to having them reference the same memory. Typically this is performed through Copy-On-Write (COW) mechanisms, such as kernel same-page merging (KSM). These mechanisms are vulnerable to attack:

  • Memory deduplication systems are vulnerable to side-channel attacks. In academic studies, attackers were able to identify software packages and versions running on neighboring virtual machines as well as software downloads and other sensitive information through analyzing memory access times on the attacker VM. Consequently, one VM can infer something about the state of another, which might not be appropriate for multi-project environments where not all projects are trusted or share the same levels of trust
  • More importantly, row-hammer type attacks have been demonstrated against KSM to enact cross-VM modification of executable memory. This means that a hostile instance can gain code-execution access to other instances on the same Compute host.

Deployers should disable KSM if they require strong project separation (as with public clouds and some private clouds):

7.2. PCI Passthrough

PCI passthrough allows an instance to have direct access to a piece of hardware on the node. For example, this could be used to allow instances to access video cards or GPUs offering the compute unified device architecture (CUDA) for high performance computation. This feature carries two types of security risks: direct memory access and hardware infection.

Direct memory access (DMA) is a feature that permits certain hardware devices to access arbitrary physical memory addresses in the host computer. Often video cards have this capability. However, an instance should not be given arbitrary physical memory access because this would give it full view of both the host system and other instances running on the same node. Hardware vendors use an input/output memory management unit (IOMMU) to manage DMA access in these situations. You should confirm that the hypervisor is configured to use this hardware feature.

A hardware infection occurs when an instance makes a malicious modification to the firmware or some other part of a device. As this device is used by other instances or the host OS, the malicious code can spread into those systems. The end result is that one instance can run code outside of its security zone. This is a significant breach as it is harder to reset the state of physical hardware than virtual hardware, and can lead to additional exposure such as access to the management network.

Due to the risk and complexities associated with PCI passthrough, it should be disabled by default. If enabled for a specific need, you will need to have appropriate processes in place to help ensure the hardware is clean before reuse.

7.3. Selinux

Mandatory access controls limit the impact an attempted attack, by restricting the privileges on QEMU process to only what is needed. On Red Hat OpenStack Platform, SELinux is configured to run each QEMU process under a separate security context. SELinux policies have been pre-configured for Red Hat OpenStack Platform services.

OpenStack’s SELinux policies intend to help protect hypervisor hosts and virtual machines against two primary threat vectors:

  • Hypervisor threats - A compromised application running within a virtual machine attacks the hypervisor to access underlying resources. For example, when a virtual machine is able to access the hypervisor OS, physical devices, or other applications. This threat vector represents considerable risk as a compromise on a hypervisor can infect the physical hardware as well as exposing other virtual machines and network segments.
  • Virtual Machine (multi-project) threats - A compromised application running within a VM attacks the hypervisor to access or control another virtual machine and its resources. This is a threat vector unique to virtualization and represents considerable risk as a multitude of virtual machine file images could be compromised due to vulnerability in a single application. This virtual network attack is a major concern as the administrative techniques for protecting real networks do not directly apply to the virtual environment. Each KVM-based virtual machine is a process which is labeled by SELinux, effectively establishing a security boundary around each virtual machine. This security boundary is monitored and enforced by the Linux kernel, restricting the virtual machine’s access to resources outside of its boundary, such as host machine data files or other VMs.

Red Hat’s SELinux-based isolation is provided regardless of the guest operating system running inside the virtual machine. Linux or Windows VMs can be used.

7.3.1. Labels and Categories

KVM-based virtual machine instances are labelled with their own SELinux data type, known as svirt_image_t. Kernel level protections prevent unauthorized system processes, such as malware, from manipulating the virtual machine image files on disk. When virtual machines are powered off, images are stored as svirt_image_t as shown below:

system_u:object_r:svirt_image_t:SystemLow image1
system_u:object_r:svirt_image_t:SystemLow image2
system_u:object_r:svirt_image_t:SystemLow image3
system_u:object_r:svirt_image_t:SystemLow image4

The svirt_image_t label uniquely identifies image files on disk, allowing for the SELinux policy to restrict access. When a KVM-based compute image is powered on, SELinux appends a random numerical identifier to the image. SELinux is capable of assigning numeric identifiers to a maximum of 524,288 virtual machines per hypervisor node, however most OpenStack deployments are highly unlikely to encounter this limitation . This example shows the SELinux category identifier:

system_u:object_r:svirt_image_t:s0:c87,c520 image1
system_u:object_r:svirt_image_t:s0:419,c172 image2

7.3.2. SELinux users and roles

SELinux manages user roles. These can be viewed through the -Z flag, or with the semanage command. On the hypervisor, only administrators should be able to access the system, and should have an appropriate context around both the administrative users and any other users that are on the system.

7.4. Containerized services

Many Red Hat OpenStack Platform services such as the Compute service (nova), the Image service (glance), and the Identity service (keystone) run in containers. With containerization, you can more easily apply updates to services. Additionally, possible vulnerabilities are isolated which reduces the attack surface to adjacent services.


Paths on the host machine that are mounted into the containers can be used as mount points to transfer data between container and host, if they are configured as ro/rw.

If you intend to test configuration options in your environment, consider the following options:

  • You can update the configuration file running within the container. The environment inside the container is ephemeral, so changes are lost when you restart the container.
  • You can update the bind-mounted configuration on the system that hosts the container. The configuration changes are lost if those configuration changes are not in heat when you next run the openstack overcloud deploy command.

Do not update service configuration files in /etc, for example, /etc/cinder/cinder.conf. This is because the containerized service does not reference this file.


For permanent configuration changes, you must modify the heat templates on Red Hat OpenStack Platform director, and re-run the openstack overcloud deploy command, using the same environment files as arguments that were used originally. Include any additional environment files that contain configuration changes.

The bind-mounted service configuration files are located in the /var/lib/config-data/puppet-generated directory. For example:

  • The Identity service: /var/lib/config-data/puppet-generated/keystone/etc/keystone/keystone.conf
  • The Block Storage service: /var/lib/config-data/puppet-generated/cinder/etc/cinder/cinder.conf
  • The Compute service: /var/lib/config-data/puppet-generated/nova_libvirt/etc/nova/nova.conf

These configuration files are generated by puppet during the initial deployment, and contain sensitive configuration information that determines the behavior of the Red Hat OpenStack cloud environment. Changes are implemented when you restart the container.

7.5. Hardening Compute Deployments

One of the main security concerns with any OpenStack deployment is the security and controls around sensitive files, such as the /var/lib/config-data/puppet-generated/nova_libvirt/etc/nova/nova.conf file. This configuration file contains many sensitive options including configuration details and service passwords. All such sensitive files should be given strict file level permissions, and monitored for changes through file integrity monitoring (FIM) tools, such as AIDE. These utilities will take a hash of the target file in a known good state, and then periodically take a new hash of the file and compare it to the known good hash. An alert can be created if it was found to have been modified unexpectedly.

The permissions of a file can be examined by moving into the directory the file is contained in and running the ls -lh command. This will show the permissions, owner, and group that have access to the file, as well as other information such as the last time the file was modified and when it was created.

The /var/lib/nova directory holds information about the instances on a given Compute node. This directory should be considered sensitive, with strictly enforced file permissions. In addition, it should be backed up regularly as it contains information and metadata for the instances associated with that host.

If your deployment does not require full virtual machine backups, consider excluding the /var/lib/nova/instances directory as it will be as large as the combined space of each instance running on that node. If your deployment does require full VM backups, you will need to ensure this directory is backed up successfully.


Data stored in the storage subsystem (for example, Ceph) being used for Block Storage (cinder) volumes should also be considered sensitive, as full virtual machine images can be retrieved from the storage subsystem if network or logical access allows this, potentially bypassing OpenStack controls.

7.6. Firmware updates

Physical servers use complex firmware to enable and operate server hardware and lights-out management cards, which can have their own security vulnerabilities, potentially allowing system access and interruption. To address these, hardware vendors will issue firmware updates, which are installed separately from operating system updates. You will need an operational security process that retrieves, tests, and implements these updates on a regular schedule, noting that firmware updates often require a reboot of physical hosts to become effective.

7.7. Block Storage

OpenStack Block Storage (cinder) is a service that provides software (services and libraries) to self-service manage persistent block-level storage devices. This creates on-demand access to Block Storage resources for use with Compute (nova) instances. This creates software-defined storage through abstraction by virtualizing pools of block storage to a variety of back-end storage devices which can be either software implementations or traditional hardware storage products. The primary functions of this is to manage the creation, attachment, and detachment of the block devices. The consumer requires no knowledge of the type of back-end storage equipment or where it is located.

Compute instances store and retrieve block storage using industry-standard storage protocols such as iSCSI, ATA over Ethernet, or Fibre-Channel. These resources are managed and configured using OpenStack native standard HTTP RESTful API.

7.7.1. Volume Wiping

There are multiple ways to wipe a block storage device. The traditional approach is to set the lvm_type to thin, and then use the volume_clear parameter. Alternatively, if the volume encryption feature is us ed, then volume wiping is not necessary if the volume encryption key is deleted.


Previously, lvm_type=default was used to signify a wipe. While this method still works, lvm_type=default is not recommended for setting secure delete.

The volume_clear parameter can accept either zero or shred as arguments. zero will write a single pass of zeroes to the device. The shred operation will write three passes of predetermined bit patterns.

7.7.2. Use keystone for authentication

In /var/lib/config-data/puppet-generated/cinder/etc/cinder/cinder.conf, check that the value of auth_strategy under the [DEFAULT] section is set to keystone and not noauth.

7.7.3. Enable TLS for authentication

In /var/lib/config-data/puppet-generated/cinder/etc/cinder/cinder.conf, check that the value of auth_uri under the [keystone_authtoken] section is set to an Identity API endpoint that starts with https:// `, and the value of the parameter `insecure also under [keystone_authtoken] is set to False.

7.7.4. Ensure Block Storage uses TLS to communicate with Compute

In cinder.conf, check that the value of glance_api_servers under the [DEFAULT] section is set to a value that starts with https://, and the value of the parameter glance_api_insecure is set to False.

7.7.5. Set the max size for the body of a request

If the maximum body size per request is not defined, the attacker can craft an arbitrary OSAPI request of large size, causing the service to crash and finally resulting in a Denial Of Service attack. Assigning t he maximum value ensures that any malicious oversized request gets blocked ensuring continued availability of the service.

Review whether max_request_body_size under the [oslo_middleware] section in cinder.conf is set to 114688.

7.7.6. Enable volume encryption

Unencrypted volume data makes volume-hosting platforms especially high-value targets for attackers, as it allows the attacker to read the data for many different VMs. In addition, the physical storage medium cou ld be stolen, remounted, and accessed from a different machine. Encrypting volume data and volume backups can help mitigate these risks and provides defense-in-depth to volume-hosting platforms. Block Storage (c inder) is able to encrypt volume data before it is written to disk, so consider enabling volume encryption, and using Barbican for private key storage.

7.8. Networking

The OpenStack Networking service (neutron) enables the end-user or project to define and consume networking resources. OpenStack Networking provides a project-facing API for defining network connectivity and IP addressing for instances in the cloud, in addition to orchestrating the network configuration. With the transition to an API-centric networking service, cloud architects and administrators should take into consideration good practices to secure physical and virtual network infrastructure and services.

OpenStack Networking was designed with a plug-in architecture that provides extensibility of the API through open source community or third-party services. As you evaluate your architectural design requirements, it is important to determine what features are available in OpenStack Networking core services, any additional services that are provided by third-party products, and what supplemental services are required to be implemented in the physical infrastructure.

This section is a high-level overview of what processes and good practices should be considered when implementing OpenStack Networking.

7.8.1. Networking architecture

OpenStack Networking is a standalone service that deploys multiple processes across a number of nodes. These processes interact with each other and other OpenStack services. The main process of the OpenStack Networking service is neutron-server, a Python daemon that exposes the OpenStack Networking API and passes project requests to a suite of plug-ins for additional processing.

The OpenStack Networking components are:

  • Neutron server (neutron-server and neutron-*-plugin) - The neutron-server service runs on the Controller node to service the Networking API and its extensions (or plugins). It also enforces the network model and IP addressing of each port. The neutron-server requires direct access to a persistent database. Agents have indirect access to the database through neutron-server, with which they communicate using AMQP (Advanced Message Queuing Protocol).
  • Neutron database - The database is the centralized source of neutron information, with the API recording all transactions in the database. This allows multiple Neutron servers to share the same database cluster, which keeps them all in sync, and allows persistence of network configuration topology.
  • Plugin agent (neutron-*-agent) - Runs on each compute node and networking node (together with the L3 and DHCP agents) to manage local virtual switch (vswitch) configuration. The enabled plug-in determines which agents are enabled. These services require message queue access and depending on the plug-in being used, access to external network controllers or SDN implementations. Some plug-ins, like OpenDaylight(ODL) and Open Virtual Network (OVN), do not require any python agents on compute nodes, requiring only an enabled Neutron plug-in for integration.
  • DHCP agent (neutron-dhcp-agent) - Provides DHCP services to project networks. This agent is the same across all plug-ins and is responsible for maintaining DHCP configuration. The neutron-dhcp-agent requires message queue access. Optional depending on plug-in.
  • Metadata agent (neutron-metadata-agent, neutron-ns-metadata-proxy) - Provides metadata services used to apply instance operating system configuration and user-supplied initialisation scripts (‘userdata’). The implementation requires the neutron-ns-metadata-proxy running in the L3 or DHCP agent namespace to intercept metadata API requests sent by cloud-init to be proxied to the metadata agent.
  • L3 agent (neutron-l3-agent) - Provides L3/NAT forwarding for external network access of VMs on project networks. Requires message queue access. Optional depending on plug-in.
  • Network provider services (SDN server/services) - Provides additional networking services to project networks. These SDN services might interact with neutron-server, neutron-plugin, and plugin-agents through communication channels such as REST APIs.

The following diagram shows an architectural and networking flow diagram of the OpenStack Networking components:

network connections

Note that this approach changes significantly when Distributed Virtual Routing (DVR) and Layer-3 High Availability (L3HA) are used. These modes change the security landscape of neutron, since L3HA implements VRRP between routers. The deployment needs to be correctly sized and hardened to help mitigate DoS attacks against routers, and local-network traffic between routers must be treated as sensitive, to help address the threat of VRRP spoofing. DVR moves networking components (such as routing) to the Compute nodes, while still requiring network nodes. As a result, the Compute nodes require access to and from public networks, increasing their exposure and requiring additional security consideration for customers, as they will need to make sure firewall rules and security model support this approach.

7.8.2. Neutron service placement on physical servers

This section describes a standard architecture that includes a controller node, a network node, and a set of compute nodes for running instances. To establish network connectivity for physical servers, a typical neutron deployment has up to four distinct physical data center networks:

network domains diagram
  • Management network - Used for internal communication between OpenStack Components. The IP addresses on this network should be reachable only within the data center and is considered the Management Security zone. By default, the Management network role is performed by the Internal API network.
  • Guest network(s) - Used for VM data communication within the cloud deployment. The IP addressing requirements of this network depend on the OpenStack Networking plug-in in use and the network configuration choices of the virtual networks made by the project. This network is considered the Guest Security zone.
  • External network - Used to provide VMs with Internet access in some deployment scenarios. The IP addresses on this network should be reachable by anyone on the Internet. This network is considered to be in the Public Security zone. This network is provided by the neutron External network(s). These neutron VLANs are hosted on the external bridge. They are not created by Red Hat OpenStack Platform director, but are created by neutron in post-deployment.
  • Public API network - Exposes all OpenStack APIs, including the OpenStack Networking API, to projects. The IP addresses on this network should be reachable by anyone on the Internet. This might be the same network as the external network, as it is possible to create a subnet for the external network that uses IP allocation ranges smaller than the full range of IP addresses in an IP block. This network is considered to be in the Public Security zone.

It is recommended you segment this traffic into separate zones. See the next section for more information.

7.8.3. Security zones

It is recommended that you use the concept of security zones to keep critical systems separate from each other. In a practical sense, this means isolating network traffic using VLANs and firewall rules. This sho uld be done with granular detail, and the result should be that only the services that need to connect to neutron are able to do so.

In the following diagram, you can see that zones have been created to separate certain components:

  • Dashboard: Accessible to public network and management network.
  • Keystone: Accessible to management network.
  • Compute node: Accessible to management network and Compute instances.
  • Network node: Accessible to management network, Compute instances, and possibly public network depending upon neutron-plugin in use.
  • SDN service node: Management services, Compute instances, and possibly public depending upon product used and configuration.
network zones


7.8.4. Networking Services

In the initial architectural phases of designing your OpenStack Network infrastructure it is important to ensure appropriate expertise is available to assist with the design of th e physical networking infrastructure, to identify proper security controls and auditing mechanisms.

OpenStack Networking adds a layer of virtualized network services which gives projects the capability to architect their own virtual networks. Currently, these virtualized service s are not as mature as their traditional networking counterparts. Consider the current state of these virtualized services before adopting them as it dictates what controls you mi ght have to implement at the virtualized and traditional network boundaries.

7.8.5. L2 isolation using VLANs and tunneling

OpenStack Networking can employ two different mechanisms for traffic segregation on a per project/network combination: VLANs (IEEE 802.1Q tagging) or L2 tunnels using VXLAN or GRE encapsulation. The scope and scale of your OpenStack deployment determines which method you should use for traffic segregation or isolation.

7.8.6. VLANs

VLANs are realized as packets on a specific physical network containing IEEE 802.1Q headers with a specific VLAN ID (VID) field value. VLAN networks sharing the same physical netw ork are isolated from each other at L2, and can even have overlapping IP address spaces. Each distinct physical network supporting VLAN networks is treated as a separate VLAN trun k, with a distinct space of VID values. Valid VID values are 1 through 4094.

VLAN configuration complexity depends on your OpenStack design requirements. To allow OpenStack Networking to more efficiently use VLANs, you must allocate a VLAN range (one for each project) and turn each Compute node physical switch port into a VLAN trunk port.

7.8.7. L2 tunneling

Network tunneling encapsulates each project/network combination with a unique tunnel-id that is used to identify the network traffic belonging to that combination. The project’s L2 network connectivity is independent of physical locality or underlying network design. By encapsulating traffic inside IP packets, that traffic can cross Layer-3 boundaries, removing the need for pre-configured VLANs and VLAN trunking. Tunneling adds a layer of obfuscation to network data traffic, reducing the visibility of individual project traffic f rom a monitoring point of view.

OpenStack Networking currently supports both GRE and VXLAN encapsulation. The choice of technology to provide L2 isolation is dependent upon the scope and size of project networks that will be created in your deployment.

7.8.8. Access control lists

Compute supports project network traffic access controls through use of the OpenStack Networking service. Security groups allow administrators and projects the ability to specify the type of traffic, and direction (ingress/egress) that is allowed to pass through a virtual interface port. Security groups rules are stateful L2-L4 traffic filters.

7.8.9. L3 routing and NAT

OpenStack Networking routers can connect multiple L2 networks, and can also provide a gateway that connects one or more private L2 networks to a shared external network, such as a public network for access to the Internet.

The L3 router provides basic Network Address Translation (SNAT and DNAT) capabilities on gateway ports that uplink the router to external networks. This router SNATs (Source NAT) all egress traffic by default, and supports floating IPs, which creates a static one-to-one bidirectional mapping from a public IP on the external network to a private IP on one o f the other subnets attached to the router. Floating IPs (through DNAT) provide external inbound connectivity to instances, and can be moved from one instances to another.

Consider using per-project L3 routing and Floating IPs for more granular connectivity of project instances. Special consideration should be given to instances connected to public networks or using Floating IPs. Usage of carefully considered security groups is recommended to filter access to only services which need to be exposed externally.

7.8.10. Quality of Service (QoS)

By default, Quality of Service (QoS) policies and rules are managed by the cloud administrator, which results in projects being unable to create specific QoS rules, or to attach s pecific policies to ports. In some use cases, such as some telecommunications applications, the administrator might trust the projects and therefore let them create and attach the ir own policies to ports. This can be done by modifying the policy.json file.

From Red Hat OpenStack Platform 12, neutron supports bandwidth-limiting QoS rules for both ingress and egress traffic. This QoS rule is named QosBandwidthLimitRule and it accept s two non-negative integers measured in kilobits per second:

  • max-kbps: bandwidth
  • max-burst-kbps: burst buffer

The QoSBandwidthLimitRule has been implemented in the neutron Open vSwitch, Linux bridge and SR-IOV drivers. However, for SR-IOV drivers, the max-burst-kbps value is not used, and is ignored if set.

The QoS rule QosDscpMarkingRule sets the Differentiated Service Code Point (DSCP) value in the type of service header on IPv4 (RFC 2474) and traffic class header on IPv6 on all traffic leaving a virtual machine, where the rule is applied. This is a 6-bit header with 21 valid values that denote the drop priority of a packet as it crosses networks should it meet congestion. It can also be used by firewalls to match valid or invalid traffic against its access control list.

7.8.11. Load balancing

The OpenStack Load-balancing service (octavia) provides a load balancing-as-a-service (LBaaS) implementation for Red Hat OpenStack platform director installations. To achieve load balancing, octavia supports enabling multiple provider drivers. The reference provider driver (Amphora provider driver) is an open-source, scalable, and highly available load bal ancing provider. It accomplishes its delivery of load balancing services by managing a fleet of virtual machines—​collectively known as amphorae—​which it spins up on demand.

For more information about the Load-balancing service, see the Using Octavia for Load Balancing-as-a-Service guide.

7.8.12. Hardening the Networking Service

This section discusses OpenStack Networking configuration good practices as they apply to project network security within your OpenStack deployment.

7.8.13. Restrict bind address of the API server: neutron-server

To restrict the interface or IP address on which the OpenStack Networking API service binds a network socket for incoming client connections, specify the bind_host and bind_por t in the /var/lib/config-data/puppet-generated/neutron/etc/neutron/neutron.conf file:

# Address to bind the API server

# Port the bind the API server to
bind_port = 9696

7.8.14. Project network services workflow

OpenStack Networking provides users self-service configuration of network resources. It is important that cloud architects and operators evaluate their design use cases in providing users the ability to create, update, and destroy available network resources.

7.8.15. Networking resource policy engine

A policy engine and its configuration file (policy.json) within OpenStack Networking provides a method to provide finer grained authorization of users on project networking methods and objects. The OpenStack N etworking policy definitions affect network availability, network security and overall OpenStack security. Cloud architects and operators should carefully evaluate their policy towards user and project access to administration of network resources.


It is important to review the default networking resource policy, as this policy can be modified to suit your security posture.

If your deployment of OpenStack provides multiple external access points into different security zones it is important that you limit the project’s ability to attach multiple vNICs to multiple external access po ints — this would bridge these security zones and could lead to unforeseen security compromise. You can help mitigate this risk by using the host aggregates functionality provided by Compute, or by splitting th e project instances into multiple projects with different virtual network configurations. For more information on host aggregates, see Creating and managing host aggregates.

7.8.16. Security groups

A security group is a collection of security group rules. Security groups and their rules allow administrators and projects the ability to specify the type of traffic and direction (ingress/egress) that is allow ed to pass through a virtual interface port. When a virtual interface port is created in OpenStack Networking it is associated with a security group. Rules can be added to the default security group in order to change the behavior on a per-deployment basis.

When using the Compute API to modify security groups, the updated security group applies to all virtual interface ports on an instance. This is due to the Compute security group APIs being instance-based rather than port-based, as found in neutron.

7.8.17. Mitigate ARP spoofing

OpenStack Networking has a built-in feature to help mitigate the threat of ARP spoofing for instances. This should not be disabled unless careful consideration is given to the resulting risks.

7.8.18. Use a Secure Protocol for Authentication

In /var/lib/config-data/puppet-generated/neutron/etc/neutron/neutron.conf check that the value of auth_uri under the [keystone_authtoken] section is set to an Identity API endpoint that starts with `https: