Overview

Heat is the main project in the OpenStack Orchestration program. It implements an orchestration engine to launch multiple composite cloud applications based on templates in the form of text files that can be treated like code.

This charm deploys the Heat infrastructure.

Usage

Heat requires the existence of the other core OpenStack services deployed via Juju charms, specifically: mysql, rabbitmq-server, keystone and nova-cloud-controller. The following assumes these services have already been deployed.

After deployment of the cloud, the domain-setup action must be run to configure required domains, roles and users in the cloud for Heat stacks.

For juju 2.x deployments use:

juju run-action heat/0 domain-setup

If using juju 1.x run:

juju action do heat/0 domain-setup

This is only required for >= OpenStack Kilo.

HA/Clustering

There are two mutually exclusive high availability options: using virtual IP(s) or DNS. In both cases, a relationship to hacluster is required which provides the corosync back end HA functionality.

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 node has an interface in said subnet. The VIP becomes a highly-available API endpoint.

At a minimum, the config option 'vip' must be set in order to use virtual IP HA. If multiple networks are being used, a VIP should be provided for each network, separated by spaces. Optionally, vip_iface or vip_cidr may be specified.

To use DNS high availability there are several prerequisites. However, DNS HA does not require the clustered nodes to be on the same subnet. Currently the DNS HA feature is only available for MAAS 2.0 or greater environments. MAAS 2.0 requires Juju 2.0 or greater. The clustered nodes must have static or "reserved" IP addresses registered in MAAS. The DNS hostname(s) must be 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 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.

The charm will throw an exception in the following circumstances: If neither 'vip' nor 'dns-ha' is set and the charm is related to hacluster If both 'vip' and 'dns-ha' are set as they are mutually exclusive If 'dns-ha' is set and none of the os-{admin,internal,public}-hostname(s) are set

Network Space support

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 heat --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:

heat:
  charm: cs:xenial/heat
  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.

Policy Overrides

This feature allows for policy overrides using the policy.d directory. This is an advanced feature and the policies that the OpenStack service supports should be clearly and unambiguously understood before trying to override, or add to, the default policies that the service uses. The charm also has some policy defaults. They should also be understood before being overridden.

Caution: It is possible to break the system (for tenants and other services) if policies are incorrectly applied to the service.

Policy overrides are YAML files that contain rules that will add to, or override, existing policy rules in the service. The policy.d directory is a place to put the YAML override files. This charm owns the /etc/heat/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 policyd-override. The resource is a ZIP file. This file, say overrides.zip, is attached to the charm by:

juju attach-resource heat policyd-override=overrides.zip

The policy override is enabled in the charm using:

juju config heat use-policyd-override=true

When use-policyd-override is True the status line of the charm will be prefixed with PO: indicating that policies have been overridden. If the 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 service. Therefore, it may be necessary to provide policy overrides for multiple service charms to achieve a consistent set of policies across the OpenStack system. The charms for the other services that may need overrides should be checked to ensure that they support overrides before proceeding.