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charm-nova-cloud-controller
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Streamline README for policy overrides 

The appendix in the deploy-guide has recently been
refreshed. This is the seventh of the nine charms that
support overrides to receive a streamlining in order
to cut down on duplication.

Some driveby formatting improvements.

Added a Bugs section.

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# nova-cloud-controller # Overview
Cloud controller node for OpenStack nova. Contains nova-schedule, nova-api, nova-network and nova-objectstore. 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 If console access is required then console-proxy-ip should be set to a client
to the nova-cloud-controller. If running in HA mode then the public vip is used if console-proxy-ip is set accessible IP that resolves to the nova-cloud-controller. If running in HA mode
to local. Note: The console access protocol is baked into a guest when it is created, if you change it then then the public vip is used if console-proxy-ip is set to local. Note: The
console access for existing guests will stop working 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
## HA/Clustering ## HA/Clustering
There are two mutually exclusive high availability options: using virtual There are two mutually exclusive high availability options: using virtual IP(s)
IP(s) or DNS. In both cases, a relationship to hacluster is required which or DNS. In both cases, a relationship to hacluster is required which provides
provides the corosync back end HA functionality. the corosync back end HA functionality.
To use virtual IP(s) the clustered nodes must be on the same subnet such that To use virtual IP(s) the clustered nodes must be on the same subnet such that
the VIP is a valid IP on the subnet for one of the node's interfaces and each the VIP is a valid IP on the subnet for one of the node's interfaces and each
@ -24,36 +28,45 @@ network, separated by spaces. Optionally, vip_iface or vip_cidr may be
specified. specified.
To use DNS high availability there are several prerequisites. However, DNS HA To use DNS high availability there are several prerequisites. However, DNS HA
does not require the clustered nodes to be on the same subnet. does not require the clustered nodes to be on the same subnet. Currently the
Currently the DNS HA feature is only available for MAAS 2.0 or greater DNS HA feature is only available for MAAS 2.0 or greater environments. MAAS 2.0
environments. MAAS 2.0 requires Juju 2.0 or greater. The clustered nodes must requires Juju 2.0 or greater. The clustered nodes must have static or
have static or "reserved" IP addresses registered in MAAS. The DNS hostname(s) "reserved" IP addresses registered in MAAS. The DNS hostname(s) must be
must be pre-registered in MAAS before use with DNS HA. pre-registered in MAAS before use with DNS HA.
At a minimum, the config option 'dns-ha' must be set to true and at least one At a minimum, the config option 'dns-ha' must be set to true and at least one
of 'os-public-hostname', 'os-internal-hostname' or 'os-internal-hostname' must of 'os-public-hostname', 'os-internal-hostname' or 'os-internal-hostname' must
be set in order to use DNS HA. One or more of the above hostnames may be set. be set in order to use DNS HA. One or more of the above hostnames may be set.
The charm will throw an exception in the following circumstances: The charm will throw an exception in the following circumstances: If neither
If neither 'vip' nor 'dns-ha' is set and the charm is related to hacluster 'vip' nor 'dns-ha' is set and the charm is related to hacluster If both 'vip'
If both 'vip' and 'dns-ha' are set as they are mutually exclusive and 'dns-ha' are set as they are mutually exclusive If 'dns-ha' is set and none
If 'dns-ha' is set and none of the os-{admin,internal,public}-hostname(s) are of the os-{admin,internal,public}-hostname(s) are set
set
## Network Space support ## 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. 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. 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. 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: 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" 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: Alternatively, these can also be provided as part of a Juju native bundle
configuration:
```yaml
nova-cloud-controller: nova-cloud-controller:
charm: cs:xenial/nova-cloud-controller charm: cs:xenial/nova-cloud-controller
num_units: 1 num_units: 1
@ -62,110 +75,108 @@ alternatively these can also be provided as part of a juju native bundle configu
admin: admin-space admin: admin-space
internal: internal-space internal: internal-space
shared-db: internal-space shared-db: internal-space
```
NOTE: Spaces must be configured in the underlying provider prior to attempting to use them. 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. 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 ## Default Quota Configuration
This charm supports default quota settings for projects. This charm supports default quota settings for projects. This feature is only
This feature is only available from Openstack Icehouse and later releases. available from OpenStack Icehouse and later releases.
The default quota settings do not overwrite post-deployment CLI quotas set by operators. The default quota settings do not overwrite post-deployment CLI quotas set by
Existing projects whose quotas were not modified will adopt the new defaults when a config-changed hook occurs. operators. Existing projects whose quotas were not modified will adopt the new
Newly created projects will also adopt the defaults set in the charm's config. 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 values below as default: By default, the charm's quota configs are not set and OpenStack projects have
quota-instances - 10 the below default values:
quota-cores - 20
quota-ram - 51200 quota-instances : 10
quota-metadata_items - 128 quota-cores : 20
quota-injected_files - 5 quota-ram : 51200
quota-injected_file_content_bytes - 10240 quota-metadata_items : 128
quota-injected_file_path_length - 255 quota-injected_files : 5
quota-key_pairs - 100 quota-injected_file_content_bytes : 10240
quota-server_groups - 10 (only available after Icehouse) quota-injected_file_path_length : 255
quota-server_group_members - 10 (only available after Icehouse) quota-key_pairs : 100
quota-server_groups : 10 (available since Juno)
quota-server_group_members : 10 (available since Juno)
## SSH knownhosts caching ## SSH knownhosts caching
This section covers the option involving the caching of SSH host lookups 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 (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 deployment of nova-compute units when first deploying a cloud, and when adding
a new unit. a new unit.
There is a Boolean configuration key `cache-known-hosts` that ensures that any 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 given host lookup to be performed just once. The default is `true` which means
that caching is performed. that caching is performed.
**Note**: A cloud can be deployed with the `cache-known-hosts` key set to > **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 `false`, and be set to `true` post-deployment. At that point the hosts will
will have been cached. The key only controls whether the cache is used or have been cached. The key only controls whether the cache is used or not.
not.
If the above key is set, a new Juju action `clear-unit-knownhost-cache` is 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 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 entire nova-cloud-controller application. This would be needed if DNS
resolution had changed in an existing cloud or during a cloud deployment. resolution had changed in an existing cloud or during a cloud deployment. Not
Not clearing the cache in such cases could result in an inconsistent set clearing the cache in such cases could result in an inconsistent set of
of knownhosts files. knownhosts files.
This action will cause DNS resolution to be performed (for This action will cause DNS resolution to be performed (for
unit/service/application), thus potentially triggering a relation-set on unit/service/application), thus potentially triggering a relation-set on the
the nova-cloud-controller unit(s) and subsequent changed hook on the nova-cloud-controller unit(s) and subsequent changed hook on the related
related nova-compute units. nova-compute units.
The action is used as follows, based on unit, service, or application, The action is used as follows, based on unit, service, or application,
respectively: 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/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 target=nova-compute juju run-action nova-cloud-controller/0 clear-unit-knownhost-cache
juju run-action nova-cloud-controller/0 clear-unit-knownhost-cache
```
In a high-availability setup, the action must be run on all In a high-availability setup, the action must be run on all
`nova-cloud-controller` units. `nova-cloud-controller` units.
# Policy Overrides ## Policy Overrides
This feature allows for policy overrides using the `policy.d` directory. This Policy overrides is an **advanced** feature that allows an operator to override
is an **advanced** feature and the policies that the OpenStack service supports the default policy of an OpenStack service. The policies that the service
should be clearly understood before trying to override, or add to, the default supports, the defaults it implements in its code, and the defaults that a charm
policies that the service uses. The charm also has some policy defaults. They may include should all be clearly understood before proceeding.
should also be understood before being overridden.
> **Caution**: It is possible to break the system (for tenants and other > **Caution**: It is possible to break the system (for tenants and other
services) if policies are incorrectly applied to the service. services) if policies are incorrectly applied to the service.
Policy overrides are YAML files that contain rules that will add to, or Policy statements are placed in a YAML file. This file (or files) is then (ZIP)
override, existing policy rules in the service. The `policy.d` directory is compressed into a single file and used as an application resource. The override
a place to put the YAML override files. This charm owns the is then enabled via a Boolean charm option.
`/etc/nova/policy.d` directory, and as such, any manual changes to it will
be overwritten on charm upgrades.
Overrides are provided to the charm using a Juju resource called Here are the essential commands (filenames are arbitrary):
`policyd-override`. The resource is a ZIP file. This file, say
`overrides.zip`, is attached to the charm by:
zip overrides.zip override-file.yaml
juju attach-resource nova-cloud-controller policyd-override=overrides.zip juju attach-resource nova-cloud-controller policyd-override=overrides.zip
The policy override is enabled in the charm using:
juju config nova-cloud-controller use-policyd-override=true juju config nova-cloud-controller use-policyd-override=true
When `use-policyd-override` is `True` the status line of the charm will be See appendix [Policy Overrides][cdg-appendix-n] in the [OpenStack Charms
prefixed with `PO:` indicating that policies have been overridden. If the Deployment Guide][cdg] for a thorough treatment of this feature.
installation of the policy override YAML files failed for any reason then the
status line will be prefixed with `PO (broken):`. The log file for the charm
will indicate the reason. No policy override files are installed if the `PO
(broken):` is shown. The status line indicates that the overrides are broken,
not that the policy for the service has failed. The policy will be the defaults
for the charm and service.
Policy overrides on one service may affect the functionality of another # Bugs
service. Therefore, it may be necessary to provide policy overrides for
multiple service charms to achieve a consistent set of policies across the Please report bugs on [Launchpad][lp-bugs-charm-nova-cloud-controller].
OpenStack system. The charms for the other services that may need overrides
should be checked to ensure that they support overrides before proceeding. For general charm questions refer to the OpenStack [Charm Guide][cg].
<!-- LINKS -->
[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