Advanced Configuration

Endpoint Network Configuration

When an OpenStack cloud is deployed, the REST API of each service is presented as a series of endpoints. These endpoints are the admin URL, the internal URL, and the external URL.

Kolla offers two options for assigning these endpoints to network addresses: - Combined - Where all three endpoints share the same IP address - Separate - Where the external URL is assigned to an IP address that is different than the IP address shared by the internal and admin URLs

The configuration parameters related to these options are: - kolla_internal_vip_address - network_interface - kolla_external_vip_address - kolla_external_vip_interface

For the combined option, set the two variables below, while allowing the other two to accept their default values. In this configuration all REST API requests, internal and external, will flow over the same network.

kolla_internal_vip_address: ""
network_interface: "eth0"

For the separate option, set these four variables. In this configuration the internal and external REST API requests can flow over separate networks.

kolla_internal_vip_address: ""
network_interface: "eth0"
kolla_external_vip_address: ""
kolla_external_vip_interface: "eth1"

Fully Qualified Domain Name Configuration

When addressing a server on the internet, it is more common to use a name, like, instead of an address like If you prefer to use names to address the endpoints in your kolla deployment use the variables:

  • kolla_internal_fqdn

  • kolla_external_fqdn


Provisions must be taken outside of kolla for these names to map to the configured IP addresses. Using a DNS server or the /etc/hosts file are two ways to create this mapping.

RabbitMQ Hostname Resolution

RabbitMQ doesn’t work with IP address, hence the IP address of api_interface should be resolvable by hostnames to make sure that all RabbitMQ Cluster hosts can resolve each others hostname beforehand.

TLS Configuration

An additional endpoint configuration option is to enable or disable TLS protection for the internal and/or external VIP. TLS allows a client to authenticate the OpenStack service endpoint and allows for encryption of the requests and responses.

The configuration variables that control TLS networking are:

  • kolla_enable_tls_external

  • kolla_external_fqdn_cert

  • kolla_enable_tls_internal

  • kolla_internal_fqdn_cert


If TLS is enabled only on the internal or the external network the kolla_internal_vip_address and kolla_external_vip_address must be different.

If there is only a single network configured in your network topology (opposed to configuring seperate internal and external networks), TLS can be enabled using only the internal network configuration variables.

The default for TLS is disabled, to enable TLS networking:

kolla_enable_tls_external: "yes"
kolla_external_fqdn_cert: "{{ node_config }}/certificates/mycert.pem"


kolla_enable_tls_internal: "yes"
kolla_internal_fqdn_cert: "{{ node_config }}/certificates/mycert-internal.pem"


TLS authentication is based on certificates that have been signed by trusted Certificate Authorities. Examples of commercial CAs are Comodo, Symantec, GoDaddy, and GlobalSign. is a CA that will provide trusted certificates at no charge. Many company’s IT departments will provide certificates within that company’s domain. If using a trusted CA is not possible for your situation, you can use OpenSSL to create your own company’s domain or see the section below about kolla generated self-signed certificates.

Two certificate files are required to use TLS securely with authentication. These two files will be provided by your Certificate Authority. These two files are the server certificate with private key and the CA certificate with any intermediate certificates. The server certificate needs to be installed with the kolla deployment and is configured with the kolla_external_fqdn_cert or kolla_internal_fqdn_cert parameter. If the server certificate provided is not already trusted by the client, then the CA certificate file will need to be distributed to the client.

When using TLS to connect to a public endpoint, an OpenStack client will have settings similar to this:

export OS_PROJECT_DOMAIN_ID=default
export OS_USER_DOMAIN_ID=default
export OS_PROJECT_NAME=demo
export OS_USERNAME=demo
export OS_PASSWORD=demo-password
export OS_AUTH_URL=
# os_cacert is optional for trusted certificates
export OS_CACERT=/etc/pki/mykolla-cacert.crt

Self-Signed Certificates


Self-signed certificates should never be used in production.

It is not always practical to get a certificate signed by a well-known trust CA, for example a development or internal test kolla deployment. In these cases it can be useful to have a self-signed certificate to use.

For convenience, the kolla-ansible command will generate the necessary certificate files based on the information in the globals.yml configuration file:

kolla-ansible certificates

The files haproxy.pem and haproxy-ca.pem will be generated and stored in the /etc/kolla/certificates/ directory.

OpenStack Service Configuration in Kolla

An operator can change the location where custom config files are read from by editing /etc/kolla/globals.yml and adding the following line.

# The directory to merge custom config files the kolla's config files
node_custom_config: "/etc/kolla/config"

Kolla allows the operator to override configuration of services. Kolla will generally look for a file in /etc/kolla/config/<< config file >>, /etc/kolla/config/<< service name >>/<< config file >> or /etc/kolla/config/<< service name >>/<< hostname >>/<< config file >>, but these locations sometimes vary and you should check the config task in the appropriate Ansible role for a full list of supported locations. For example, in the case of nova.conf the following locations are supported, assuming that you have services using nova.conf running on hosts called controller-0001, controller-0002 and controller-0003:

  • /etc/kolla/config/nova.conf

  • /etc/kolla/config/nova/controller-0001/nova.conf

  • /etc/kolla/config/nova/controller-0002/nova.conf

  • /etc/kolla/config/nova/controller-0003/nova.conf

  • /etc/kolla/config/nova/nova-scheduler.conf

Using this mechanism, overrides can be configured per-project, per-project-service or per-project-service-on-specified-host.

Overriding an option is as simple as setting the option under the relevant section. For example, to set override scheduler_max_attempts in nova scheduler, the operator could create /etc/kolla/config/nova/nova-scheduler.conf with content:

scheduler_max_attempts = 100

If the operator wants to configure compute node cpu and ram allocation ratio on host myhost, the operator needs to create file /etc/kolla/config/nova/myhost/nova.conf with content:

cpu_allocation_ratio = 16.0
ram_allocation_ratio = 5.0

This method of merging configuration sections is supported for all services using Oslo Config, which includes the vast majority of OpenStack services, and in some cases for services using YAML configuration. Since the INI format is an informal standard, not all INI files can be merged in this way. In these cases Kolla supports overriding the entire config file.

Additional flexibility can be introduced by using Jinja conditionals in the config files. For example, you may create Nova cells which are homogeneous with respect to the hypervisor model. In each cell, you may wish to configure the hypervisors differently, for example the following override shows one way of setting the bandwidth_poll_interval variable as a function of the cell:

{% if 'cell0001' in group_names %}
bandwidth_poll_interval = 100
{% elif 'cell0002' in group_names %}
bandwidth_poll_interval = -1
{% else %}
bandwidth_poll_interval = 300
{% endif %}

An alternative to Jinja conditionals would be to define a variable for the bandwidth_poll_interval and set it in according to your requirements in the inventory group or host vars:

bandwidth_poll_interval = {{ bandwidth_poll_interval }}

Kolla allows the operator to override configuration globally for all services. It will look for a file called /etc/kolla/config/global.conf.

For example to modify database pool size connection for all services, the operator needs to create /etc/kolla/config/global.conf with content:

max_pool_size = 100

OpenStack policy customisation

OpenStack services allow customisation of policy. Since the Queens release, default policy configuration is defined within the source code for each service, meaning that operators only need to override rules they wish to change. Projects typically provide documentation on their default policy configuration, for example, Keystone.

Policy can be customised via JSON or YAML files. As of the Wallaby release, the JSON format is deprecated in favour of YAML. One major benefit of YAML is that it allows for the use of comments.

For example, to customise the Neutron policy in YAML format, the operator should add the customised rules in /etc/kolla/config/neutron/policy.yaml.

The operator can make these changes after services have been deployed by using the following command:

kolla-ansible deploy

In order to present a user with the correct interface, Horizon includes policy for other services. Customisations made to those services may need to be replicated in Horizon. For example, to customise the Neutron policy in YAML format for Horizon, the operator should add the customised rules in /etc/kolla/config/horizon/neutron_policy.yaml.

IP Address Constrained Environments

If a development environment doesn’t have a free IP address available for VIP configuration, the host’s IP address may be used here by disabling HAProxy by adding:

enable_haproxy: "no"

Note this method is not recommended and generally not tested by the Kolla community, but included since sometimes a free IP is not available in a testing environment.

External Elasticsearch/Kibana environment

It is possible to use an external Elasticsearch/Kibana environment. To do this first disable the deployment of the central logging.

enable_central_logging: "no"

Now you can use the parameter elasticsearch_address to configure the address of the external Elasticsearch environment.

Non-default <service> port

It is sometimes required to use a different than default port for service(s) in Kolla. It is possible with setting <service>_port in globals.yml file. For example:

database_port: 3307

As <service>_port value is saved in different services’ configuration so it’s advised to make above change before deploying.

Use an external Syslog server

By default, Fluentd is used as a syslog server to collect Swift and HAProxy logs. When Fluentd is disabled or you want to use an external syslog server, You can set syslog parameters in globals.yml file. For example:

syslog_server: ""
syslog_udp_port: "514"

You can also set syslog facility names for Swift and HAProxy logs. By default, Swift and HAProxy use local0 and local1, respectively.

syslog_swift_facility: "local0"
syslog_haproxy_facility: "local1"

Mount additional Docker volumes in containers

It is sometimes useful to be able to mount additional Docker volumes into one or more containers. This may be to integrate 3rd party components into OpenStack, or to provide access to site-specific data such as x.509 certificate bundles.

Additional volumes may be specified at three levels:

  • globally

  • per-service (e.g. nova)

  • per-container (e.g. nova-api)

To specify additional volumes globally for all containers, set default_extra_volumes in globals.yml. For example:

  - "/etc/foo:/etc/foo"

To specify additional volumes for all containers in a service, set <service_name>_extra_volumes in globals.yml. For example:

  - "/etc/foo:/etc/foo"

To specify additional volumes for a single container, set <container_name>_extra_volumes in globals.yml. For example:

  - "/etc/foo:/etc/foo"