Glossary

Bundle

Definition: A collection of Operator CSV, manifests, and metadata which together form a unique version of an Operator that can be installed onto the cluster.

Bundle Image

Definition: An image of a bundle is built from operator manifests and contains exactly one bundle. The bundle images are stored and distributed by OCI spec container registries such as Quay.io or DockerHub.

Channel

Definition: The channel defines a stream of updates for an operator and is used to roll out updates for subscribers. The head points at the latest version of that channel. For example, a stable channel would have all stable versions of an operator arranged from the earliest to the latest. An operator can have several channels, and a subscription binding to a certain channel would only look for updates in that channel.

Channel Head

Definition: Head refers to the latest known update in a particular channel.

Catalog Image

Definition: A catalog image is a containerized datastore that describes a set of operator and update metadata that can be installed onto a cluster via OLM.

Aliases: OPM Index

Dependency

Definition: An Operator may have a dependency on another Operator being present in the cluster. For example, the Vault Operator has a dependency on the Etcd Operator for its data persistence layer. OLM resolves these dependencies by ensuring all specified versions of Operators and CRDs are installed on the cluster during the installation phase. This dependency is resolved by finding and installing an Operator in a Catalog that satisfies the required CRD API, and not related to packages/bundles.

Aliases: Operator Dependency, GVK Dependency, API Dependency, Required CRD

Index

Definition: The Index refers to an image of a database (a database snapshot) that contains information about Operator bundles including CSVs, CRDs, etc of all versions. This index can host a history of used operators on a cluster and be maintained by adding or removing operators.

Aliases: Registry DB, Catalog DB, OPM registry

Package

Definition: A package is a directory that encloses all released history of an Operator with each version contained in the bundle format. A released version of an Operator is described in a ClusterServiceVersion manifest alongside the CustomResourceDefinitions.

Registry

Definition: A database which stores Bundle Images of Operators, each with all of its latest/historical versions in all channels.

Update Graph

Definition: An upgrade graph links versions of CSV together, similar to the upgrade graph of any other packaged software. Operators can be installed sequentially, or certain versions can be skipped. The update graph is expected to grow only at the head with newer versions being added.