红帽全球峰会3.2. OpenShift Container Storage operator
The ocs-operator can be described as a "meta" operator for OpenShift Data Foundation, that is, an operator meant to influence other operators and serves as a configuration gateway for the features provided by the other operators. It does not directly manage the other operators.
The ocs-operator has the following primary functions:
- Creates Custom Resources (CRs) that trigger the other operators to reconcile against them.
- Abstracts the Ceph and Multicloud Object Gateway configurations and limits them to known best practices that are validated and supported by Red Hat.
- Creates and reconciles the resources required to deploy containerized Ceph and NooBaa according to the support policies.
3.2.1. Components
The ocs-operator does not have any dependent components. However, the operator has a dependency on the existence of all the custom resource definitions (CRDs) from other operators, which are defined in the ClusterServiceVersion (CSV).
3.2.2. Design diagram
This diagram illustrates how OpenShift Container Storage is integrated with the OpenShift Container Platform.
图 3.2. OpenShift Container Storage Operator
3.2.3. Responsibilities
The two ocs-operator CRDs are:
-
OCSInitialization -
StorageCluster
OCSInitialization is a singleton CRD used for encapsulating operations that apply at the operator level. The operator takes care of ensuring that one instance always exists. The CR triggers the following:
Performs initialization tasks required for OpenShift Container Storage. If needed, these tasks can be triggered to run again by deleting the
OCSInitializationCRD.- Ensures that the required Security Context Constraints (SCCs) for OpenShift Container Storage are present.
- Manages the deployment of the Ceph toolbox Pod, used for performing advanced troubleshooting and recovery operations.
The StorageCluster CRD represents the system that provides the full functionality of OpenShift Container Storage. It triggers the operator to ensure the generation and reconciliation of Rook-Ceph and NooBaa CRDs. The ocs-operator algorithmically generates the CephCluster and NooBaa CRDs based on the configuration in the StorageCluster spec. The operator also creates additional CRs, such as CephBlockPools, Routes, and so on. These resources are required for enabling different features of OpenShift Container Storage. Currently, only one StorageCluster CR per OpenShift Container Platform cluster is supported.
3.2.4. Resources
The ocs-operator creates the following CRs in response to the spec of the CRDs it defines . The configuration of some of these resources can be overridden, allowing for changes to the generated spec or not creating them altogether.
- General resources
- Events
- Creates various events when required in response to reconciliation.
- Persistent Volumes (PVs)
- PVs are not created directly by the operator. However, the operator keeps track of all the PVs created by the Ceph CSI drivers and ensures that the PVs have appropriate annotations for the supported features.
- Quickstarts
- Deploys various Quickstart CRs for the OpenShift Container Platform Console.
- Rook-Ceph resources
CephBlockPool-
Define the default Ceph block pools.
CephFilesysPrometheusRulesoutefor the Ceph object store. StorageClass-
Define the default Storage classes. For example, for
CephBlockPoolandCephFilesystem). VolumeSnapshotClass- Define the default volume snapshot classes for the corresponding storage classes.
- Multicloud Object Gateway resources
NooBaa- Define the default Multicloud Object Gateway system.
- Monitoring resources
- Metrics Exporter Service
- Metrics Exporter Service Monitor
- PrometheusRules
3.2.5. Limitation
The ocs-operator neither deploys nor reconciles the other Pods of OpenShift Data Foundation. The ocs-operator CSV defines the top-level components such as operator Deployments and the Operator Lifecycle Manager (OLM) reconciles the specified component.
3.2.6. High availability
High availability is not a primary requirement for the ocs-operator Pod similar to most of the other operators. In general, there are no operations that require or benefit from process distribution. OpenShift Container Platform quickly spins up a replacement Pod whenever the current Pod becomes unavailable or is deleted.
3.2.7. Relevant config files
The ocs-operator configuration is entirely specified by the CSV and is not modifiable without a custom build of the CSV.
3.2.8. Relevant log files
To get an understanding of the OpenShift Container Storage and troubleshoot issues, you can look at the following:
- Operator Pod logs
- StorageCluster status and events
- OCSInitialization status
Operator Pod logs
Each operator provides standard Pod logs that include information about reconciliation and errors encountered. These logs often have information about successful reconciliation which can be filtered out and ignored.
StorageCluster status and events
The StorageCluster CR stores the reconciliation details in the status of the CR and has associated events. Status contains a section of the expected container images. It shows the container images that it expects to be present in the pods from other operators and the images that it currently detects. This helps to determine whether the OpenShift Container Storage upgrade is complete.
OCSInitialization status
This status shows whether the initialization tasks are completed successfully.
3.2.9. Lifecycle
The ocs-operator is required to be present as long as the OpenShift Container Storage bundle remains installed. This is managed as part of OLM’s reconciliation of the OpenShift Container Storage CSV. At least one instance of the pod should be in Ready state.
The operator operands such as CRDs should not affect the lifecycle of the operator. An OCSInitialization CR should always exist. The operator creates one if it does not exist. The creation and deletion of StorageClusters is an operation outside the operator’s control and must be initiated by the administrator or automated with the appropriate API calls.
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