GlossaryΒΆ

Administrator
An administrator of Continuuity Loom defines the various configuration elements for creating clusters in Continuuity Loom. These include settings such as the provider to host the cluster, the hardware configuration of the nodes, the base disk image of nodes, the software services installed on the cluster, and the duration of lease on the clusters. These settings are all tied together via templates that can be used by Loom users to create clusters. In addition, an administrator can monitor, manage and delete the clusters created across all users.
Catalog
A catalog is a list containing the templates created by the administrator. All templates in the catalog are available to users for cluster creation. The catalog can be accessed through the Admin UI or through calls to the REST API. For a user, the catalog is displayed under ‘Template’ when creating a new cluster.
Chef
Chef is an automation platform that transforms infrastructure configurations into code. It is used to simplify server maintenance and creation tasks, and is especially useful for repeatability in server configurations.
Cluster
A cluster is a group of machines, each of which uses some hardware, image, and at least one service. It is created by end users from a template.
Constraints
Cluster templates contain constraints that describe how services, hardware, and images should come together during cluster creation. Service constraints can limit what hardware and image a service can be placed on a cluster, as well as limit the maximum or minimum instances of that service across the entire cluster. Layout constraints can force certain service groups to always coexist on the same node, and can force certain service groups to never coexist on the same node. Constraints are local to a cluster template, and can differ across templates.
Expiry Time
The expiry time of a cluster indicates the time at which the cluster will be automatically deleted.
Hardware
Hardware in Continuuity Loom refers to a type of machine, either physical or in the cloud, that a Provider can provide.
Image
An Image in Continuuity Loom refers to some type of base image that a Provider can provide. Any software that the image may contain is not managed by Continuuity Loom. Its main use is to specify the OS on a machine.
Lease Time
A lease time is an optional cluster setting that specifies the amount of time a cluster can run for before being automatically deleted.
Loom Server
The Loom Server is a component of Continuuity Loom that stores admin defined providers, hardware types, image types, services, and cluster templates. Loom server takes cluster action requests, such as requests to create or delete a cluster. It also manages the tasks each node need to run, as well as the order of tasks to complete the actions.
Provider
A provider is responsible for providing a machine. Examples include an Openstack instance, Rackspace, and Amazon EC2.
Provisioner
The provisioner is a component of Continuuity Loom that performs cluster management tasks. It performs all the actual tasks, including communicating with different providers to request machines, installing services, and configuring services.
Service
A service in Continuuity Loom is a piece of software that can be made available on a cluster. It defines at least one provisioner action that will occur during cluster creation and management. Provisioner actions fall into one of the following types: install, configure, initialize, start, stop, and remove.
Solver
The solver is the component in Loom Server that takes a cluster template and a cluster request, and determines the services to place on each node, based on their image and hardware type. The solver also performs similar tasks when a cluster is scaled up or down.
Template
A cluster template is a blueprint describing how clusters should be laid out. It defines services, hardware types, and images types that can be used to create a cluster, as well as default values for lease times, services, hardware, image, and provider to be used with the cluster. In addition, a set of constraints is specified to determine how many nodes should have different services, and what services can and cannot exist together on the same node.
User
A user of Loom can create clusters through Continuuity Loom within the permitted configurations set by the Administrator, as specified through the templates in the catalog.
Zookeeper
ZooKeeper is a centralized service for maintaining metadata, naming, providing distributed synchronization, and providing group services. ZooKeeper provides a distributed system that allows decisions to be made by quorum.

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