This section discusses OpenStack Networking configuration best practices as they apply to tenant network security within your OpenStack deployment.
OpenStack Networking provides users real self services of network resources and configurations. 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.
A policy engine and its configuration file,
policy.json, within OpenStack Networking
provides a method to provide finer grained authorization of
users on tenant networking methods and objects. It is important
that cloud architects and operators evaluate their design and
use cases in providing users and tenants the ability to create,
update, and destroy available network resources as it has a
tangible effect on tenant network availability, network
security, and overall OpenStack security. For a more detailed
explanation of OpenStack Networking policy definition, please
refer to the Authentication
and authorization section in the OpenStack
Cloud Administrator Guide.
It is important to review the default networking resource policy and modify the policy appropriately for your security posture.
If your deployment of OpenStack provides multiple external access points into different security domains it is important that you limit the tenant's ability to attach multiple vNICs to multiple external access points -- this would bridge these security domains and could lead to unforeseen security compromise. It is possible mitigate this risk by utilizing the host aggregates functionality provided by OpenStack Compute or through splitting the tenant VMs into multiple tenant projects with different virtual network configurations.
The OpenStack Networking Service provides security group functionality using a mechanism that is more flexible and powerful than the security group capabilities built into OpenStack Compute. Thus, when using OpenStack Networking, nova.conf should always disable built-in security groups and proxy all security group calls to the OpenStack Networking API. Failure to do so will result in conflicting security policies being simultaneously applied by both services. To proxy security groups to OpenStack Networking, use the following configuration values:
firewall_driver : must be set to 'nova.virt.firewall.NoopFirewallDriver' so that
nova-computedoes not perform iptables-based filtering itself.security_group_api : must be set to 'neutron' so that all security group requests are proxied to the OpenStack Network Service.
Security groups and security group rules allow administrators and tenants the ability to specify the type of traffic and direction (ingress/egress) that is allowed to pass through a virtual interface port. A security group is a container for security group rules. When a virtual interface port is created in OpenStack Networking it is associated with a security group. If a security group is not specified, the port will be associated with a 'default' security group. By default this group will drop all ingress traffic and allow all egress. Rules can be added to this group in order to change the behaviour.
When using the security group API through OpenStack Compute, security groups are applied to all virtual interface ports on an instance. The reason for this is that OpenStack Compute security group APIs are instance based and not virtual interface port based as OpenStack Networking.
Quotas provide the ability to limit the number of network resources available to tenants. You can enforce default quotas for all tenants.
/etc/neutron/neutron.conf [QUOTAS] # resource name(s) that are supported in quota features quota_items = network,subnet,port # default number of resource allowed per tenant, minus for unlimited #default_quota = -1 # number of networks allowed per tenant, and minus means unlimited quota_network = 10 # number of subnets allowed per tenant, and minus means unlimited quota_subnet = 10 # number of ports allowed per tenant, and minus means unlimited quota_port = 50 # number of security groups allowed per tenant, and minus means unlimited quota_security_group = 10 # number of security group rules allowed per tenant, and minus means unlimited quota_security_group_rule = 100 # default driver to use for quota checks quota_driver = neutron.quota.ConfDriver
OpenStack Networking also supports per-tenant quotas limit via a quota extension API. To enable per-tenant quotas, you need to set quota_driver in neutron.conf.
quota_driver = neutron.db.quota_db.DbQuotaDriver
