Operators are among the most important components of Red Hat OpenShift Service on AWS. Operators are the preferred method of packaging, deploying, and managing services on the control plane. They can also provide advantages to applications that users run.
Operators integrate with Kubernetes APIs and CLI tools such as
oc commands. They provide the means of monitoring applications, performing health checks, managing over-the-air (OTA) updates, and ensuring that applications remain in your specified state.
While both follow similar Operator concepts and goals, Operators in Red Hat OpenShift Service on AWS are managed by two different systems, depending on their purpose:
Cluster Operators, which are managed by the Cluster Version Operator (CVO), are installed by default to perform cluster functions.
Optional add-on Operators, which are managed by Operator Lifecycle Manager (OLM), can be made accessible for users to run in their applications.
With Operators, you can create applications to monitor the running services in the cluster. Operators are designed specifically for your applications. Operators implement and automate the common Day 1 operations such as installation and configuration as well as Day 2 operations such as autoscaling up and down and creating backups. All these activities are in a piece of software running inside your cluster.
In Red Hat OpenShift Service on AWS, all cluster functions are divided into a series of default cluster Operators. Cluster Operators manage a particular area of cluster functionality, such as cluster-wide application logging, management of the Kubernetes control plane, or the machine provisioning system.
Cluster Operators are represented by a
ClusterOperator object, which
administrators with the
can view in the Red Hat OpenShift Service on AWS web console from the Administration → Cluster Settings page. Each cluster Operator provides a simple API for determining cluster functionality. The Operator hides the details of managing the lifecycle of that component. Operators can manage a single component or tens of components, but the end goal is always to reduce operational burden by automating common actions.
Operator Lifecycle Manager (OLM) and OperatorHub are default components in Red Hat OpenShift Service on AWS that help manage Kubernetes-native applications as Operators. Together they provide the system for discovering, installing, and managing the optional add-on Operators available on the cluster.
Using OperatorHub in the Red Hat OpenShift Service on AWS web console,
administrators with the
and authorized users can select Operators to install from catalogs of Operators. After installing an Operator from OperatorHub, it can be made available globally or in specific namespaces to run in user applications.
Default catalog sources are available that include Red Hat Operators, certified Operators, and community Operators.
Administrators with the
can also add their own custom catalog sources, which can contain a custom set of Operators.
All Operators listed in the Operator Hub marketplace should be available for installation. These Operators are considered customer workloads, and are not monitored by Red Hat Site Reliability Engineering (SRE).
Developers can use the Operator SDK to help author custom Operators that take advantage of OLM features, as well. Their Operator can then be bundled and added to a custom catalog source, which can be added to a cluster and made available to users.
OLM does not manage the cluster Operators that comprise the Red Hat OpenShift Service on AWS architecture.
As a developer, you can perform the following Operator tasks:
To understand more about Operators, see What are Operators?