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This topic describes the resource charms used by Charmed OpenStack. They are deploying supporting services that are necessary for integrating all OpenStack services together.
MySQL InnoDB Cluster is high availability and high scalability solution for MySQL clustering. It allows benefiting from the native MySQL database server clustering feature.
Note: MySQL InnoDB Cluster is not a 'scale-out' MySQL solution. Reads and writes are channeled through a single service unit and synchronously replicated to other nodes in the cluster. Reads/writes are as slow as the slowest node your deployment.
A subordinate charm that is proxying the communication between the application client and the MySQL InnoDB cluster. It is used together with mysql-inodb-cluster charm and the principle charm which the application is supposed to communicate with the MySQL database.
RabbitMQ is an implementation of AMQP, the emerging standard for high-performance enterprise messaging. The RabbitMQ server is a robust and scalable implementation of an AMQP broker. This charm deploys the RabbitMQ server and provides AMQP connectivity to clients.
When more than one unit of the charm is deployed, the charm will bring up a native RabbitMQ cluster. The process of clustering the units together takes some time.
Note: Due to the nature of asynchronous hook execution, it is possible that client relationship hooks may be executed before the cluster is complete. In some cases, this can lead to client charm errors. Single unit deployments behave as expected.
Vault secures, stores, and tightly controls access to tokens, passwords, certificates, API keys, and other secrets in modern computing. Vault handles leasing, key revocation, key rolling, and auditing. Through a unified API, users can access an encrypted Key/Value store and network encryption-as-a-service, or generate AWS IAM/STS credentials, SQL/NoSQL databases, X.509 certificates, SSH credentials, and more.
In Charmed OpenStack Vault is used for storing all necessary encryption keys for the variety of service such as Ceph, MySQL and other.
It allows you to enable encryption-at-rest for Ceph, as well as encrypt the traffic between the OpenStack services, databases, and the queuing services.
This subordinate charm provides corosync and pacemaker cluster configuration for principle charms which support the hacluster, container scoped relation.
There are two mutually exclusive HA options available:
In this Reference Architecture, deployment and testing the HA option used is the VIP. In both cases, a relationship to hacluster is required, which provides the Corosync back end HA functionality. To use virtual IP address(es) the clustered nodes must be on the same subnet, such that:
The VIP becomes a highly available API endpoint.
At a minimum, the configuration 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.
There are several prerequisites to use DNS high availability. However, DNS HA does not require the clustered nodes to be on the same subnet.
At a minimum, the configuration option, dns-ha, must be set to true, and at least one or more of the following hostnames must be set, in order to use DNS HA:
The charm will throw an exception in the following circumstances:
All the OpenStack services will be deployed in highly available mode, and each service will have three units; each one running on an LXC container in a separate hypervisor. The Charmed OpenStack provides high availability for all OpenStack services as well as HA Juju. The following diagram explains the different types of HA used in Charmed OpenStack:
The ntp charm is a subordinate charm that is designed for use with other principal charms. In its basic mode, the ntp charm is used to configure NTP in service units to talk directly to a set of NTP time sources.