Chapter 21. Glossary
This glossary defines common terms that are used in the logging documentation.
- Annotation
- You can use annotations to attach metadata to objects.
- Red Hat OpenShift Logging Operator
- The Red Hat OpenShift Logging Operator provides a set of APIs to control the collection and forwarding of application, infrastructure, and audit logs.
- Custom resource (CR)
-
A CR is an extension of the Kubernetes API. To configure the logging and log forwarding, you can customize the
ClusterLoggingand theClusterLogForwardercustom resources. - Event router
- The event router is a pod that watches OpenShift Container Platform events. It collects logs by using the logging.
- Fluentd
- Fluentd is a log collector that resides on each OpenShift Container Platform node. It gathers application, infrastructure, and audit logs and forwards them to different outputs.
- Garbage collection
- Garbage collection is the process of cleaning up cluster resources, such as terminated containers and images that are not referenced by any running pods.
- Elasticsearch
- Elasticsearch is a distributed search and analytics engine. OpenShift Container Platform uses Elasticsearch as a default log store for the logging.
- OpenShift Elasticsearch Operator
- The OpenShift Elasticsearch Operator is used to run an Elasticsearch cluster on OpenShift Container Platform. The OpenShift Elasticsearch Operator provides self-service for the Elasticsearch cluster operations and is used by the logging.
- Indexing
- Indexing is a data structure technique that is used to quickly locate and access data. Indexing optimizes the performance by minimizing the amount of disk access required when a query is processed.
- JSON logging
- The Log Forwarding API enables you to parse JSON logs into a structured object and forward them to either the logging managed Elasticsearch or any other third-party system supported by the Log Forwarding API.
- Kibana
- Kibana is a browser-based console interface to query, discover, and visualize your Elasticsearch data through histograms, line graphs, and pie charts.
- Kubernetes API server
- Kubernetes API server validates and configures data for the API objects.
- Labels
- Labels are key-value pairs that you can use to organize and select subsets of objects, such as a pod.
- Logging
- With the logging, you can aggregate application, infrastructure, and audit logs throughout your cluster. You can also store them to a default log store, forward them to third party systems, and query and visualize the stored logs in the default log store.
- Logging collector
- A logging collector collects logs from the cluster, formats them, and forwards them to the log store or third party systems.
- Log store
- A log store is used to store aggregated logs. You can use an internal log store or forward logs to external log stores.
- Log visualizer
- Log visualizer is the user interface (UI) component you can use to view information such as logs, graphs, charts, and other metrics.
- Node
- A node is a worker machine in the OpenShift Container Platform cluster. A node is either a virtual machine (VM) or a physical machine.
- Operators
- Operators are the preferred method of packaging, deploying, and managing a Kubernetes application in an OpenShift Container Platform cluster. An Operator takes human operational knowledge and encodes it into software that is packaged and shared with customers.
- Pod
- A pod is the smallest logical unit in Kubernetes. A pod consists of one or more containers and runs on a worker node.
- Role-based access control (RBAC)
- RBAC is a key security control to ensure that cluster users and workloads have access only to resources required to execute their roles.
- Shards
- Elasticsearch organizes log data from Fluentd into datastores, or indices, then subdivides each index into multiple pieces called shards.
- Taint
- Taints ensure that pods are scheduled onto appropriate nodes. You can apply one or more taints on a node.
- Toleration
- You can apply tolerations to pods. Tolerations allow the scheduler to schedule pods with matching taints.
- Web console
- A user interface (UI) to manage OpenShift Container Platform.
