# Overview Cloud controller node for OpenStack nova. Contains nova-schedule, nova-api, nova-network and nova-objectstore. If console access is required then console-proxy-ip should be set to a client accessible IP that resolves to the nova-cloud-controller. If running in HA mode then the public vip is used if console-proxy-ip is set to local. Note: The console access protocol is baked into a guest when it is created, if you change it then console access for existing guests will stop working # Usage ## High availability When more than one unit is deployed with the [hacluster][hacluster-charm] application the charm will bring up an HA active/active cluster. There are two mutually exclusive high availability options: using virtual IP(s) or DNS. In both cases the hacluster subordinate charm is used to provide the Corosync and Pacemaker backend HA functionality. See [OpenStack high availability][cdg-ha-apps] in the [OpenStack Charms Deployment Guide][cdg] for details. ## Spaces This charm supports the use of Juju Network Spaces, allowing the charm to be bound to network space configurations managed directly by Juju. This is only supported with Juju 2.0 and above. API endpoints can be bound to distinct network spaces supporting the network separation of public, internal and admin endpoints. Access to the underlying MySQL instance can also be bound to a specific space using the shared-db relation. To use this feature, use the --bind option when deploying the charm: juju deploy nova-cloud-controller --bind \ "public=public-space \ internal=internal-space \ admin=admin-space \ shared-db=internal-space" Alternatively, these can also be provided as part of a Juju native bundle configuration: ```yaml nova-cloud-controller: charm: cs:xenial/nova-cloud-controller num_units: 1 bindings: public: public-space admin: admin-space internal: internal-space shared-db: internal-space ``` NOTE: Spaces must be configured in the underlying provider prior to attempting to use them. NOTE: Existing deployments using os-*-network configuration options will continue to function; these options are preferred over any network space binding provided if set. ## Default Quota Configuration This charm supports default quota settings for projects. This feature is only available from OpenStack Icehouse and later releases. The default quota settings do not overwrite post-deployment CLI quotas set by operators. Existing projects whose quotas were not modified will adopt the new defaults when a config-changed hook occurs. Newly created projects will also adopt the defaults set in the charm's config. By default, the charm's quota configs are not set and OpenStack projects have the below default values: quota-instances : 10 quota-cores : 20 quota-ram : 51200 quota-metadata_items : 128 quota-injected_files : 5 quota-injected_file_content_bytes : 10240 quota-injected_file_path_length : 255 quota-key_pairs : 100 quota-server_groups : 10 (available since Juno) quota-server_group_members : 10 (available since Juno) ## SSH knownhosts caching This section covers the option involving the caching of SSH host lookups (knownhosts) on each nova-compute unit. Caching of SSH host lookups speeds up deployment of nova-compute units when first deploying a cloud, and when adding a new unit. There is a Boolean configuration key `cache-known-hosts` that ensures that any given host lookup to be performed just once. The default is `true` which means that caching is performed. > **Note**: A cloud can be deployed with the `cache-known-hosts` key set to `false`, and be set to `true` post-deployment. At that point the hosts will have been cached. The key only controls whether the cache is used or not. If the above key is set, a new Juju action `clear-unit-knownhost-cache` is provided to clear the cache. This can be applied to a unit, service, or an entire nova-cloud-controller application. This would be needed if DNS resolution had changed in an existing cloud or during a cloud deployment. Not clearing the cache in such cases could result in an inconsistent set of knownhosts files. This action will cause DNS resolution to be performed (for unit/service/application), thus potentially triggering a relation-set on the nova-cloud-controller unit(s) and subsequent changed hook on the related nova-compute units. The action is used as follows, based on unit, service, or application, respectively: juju run-action nova-cloud-controller/0 clear-unit-knownhost-cache target=nova-compute/2 juju run-action nova-cloud-controller/0 clear-unit-knownhost-cache target=nova-compute juju run-action nova-cloud-controller/0 clear-unit-knownhost-cache In a high-availability setup, the action must be run on all `nova-cloud-controller` units. ## Policy Overrides Policy overrides is an **advanced** feature that allows an operator to override the default policy of an OpenStack service. The policies that the service supports, the defaults it implements in its code, and the defaults that a charm may include should all be clearly understood before proceeding. > **Caution**: It is possible to break the system (for tenants and other services) if policies are incorrectly applied to the service. Policy statements are placed in a YAML file. This file (or files) is then (ZIP) compressed into a single file and used as an application resource. The override is then enabled via a Boolean charm option. Here are the essential commands (filenames are arbitrary): zip overrides.zip override-file.yaml juju attach-resource nova-cloud-controller policyd-override=overrides.zip juju config nova-cloud-controller use-policyd-override=true See appendix [Policy Overrides][cdg-appendix-n] in the [OpenStack Charms Deployment Guide][cdg] for a thorough treatment of this feature. # Bugs Please report bugs on [Launchpad][lp-bugs-charm-nova-cloud-controller]. For general charm questions refer to the OpenStack [Charm Guide][cg]. [cg]: https://docs.openstack.org/charm-guide [cdg]: https://docs.openstack.org/project-deploy-guide/charm-deployment-guide [cdg-appendix-n]: https://docs.openstack.org/project-deploy-guide/charm-deployment-guide/latest/app-policy-overrides.html [lp-bugs-charm-nova-cloud-controller]: https://bugs.launchpad.net/charm-nova-cloud-controller/+filebug [cdg-ha-apps]: https://docs.openstack.org/project-deploy-guide/charm-deployment-guide/latest/app-ha.html#ha-applications [hacluster-charm]: https://jaas.ai/hacluster