About Creating TimesTen Databases

The TimesTen Operator creates, manages, and monitors TimesTen Classic databases. It supports the following topologies:

Replicated active standby pair configurations: The TimesTen Operator configures one TimesTen database as the active database, copies the active database to the standby, and configures an active standby pair replication scheme between them.
Non-replicated configurations: The TimesTen Operator configures one or more TimesTen Classic databases. Each database is independent and has no relationship to each other.

You use the ttclassic Helm chart to create TimesTen Classic databases for both replicated and non-replicated configurations. To distinguish the two configurations, the ttclassic chart provides the replicationTopology variable. Let's look at an example and then discuss the specifics.

Here are two YAML files that define the variables for both configurations. How you use these files to create TimesTen databases is discussed in a later section.

Replicated:
```
storageClassName: oci-bv
storageSize: 10Gi
image:
  repository: container-registry.oracle.com/timesten/timesten
  tag: "22.1.1.27.0"
imagePullSecret: sekret
replicationTopology: activeStandbyPair
dbConfigMap:
  - name: repsamplehelm
  directory: cm
```
The replicationTopology variable has a value of activeStandbyPair, indicating a replicated configuration in which the TimesTen Operator creates an active standby pair of TimesTen databases. Since the default value for the replicationTopology variable is activeStandbyPair, you have the option of not specifying the replicationTopology variable for replicated configurations.
Non-replicated:
```
storageClassName: oci-bv
storageSize: 10Gi
image:
  repository: container-registry.oracle.com/timesten/timesten
  tag: "22.1.1.27.0"
imagePullSecret: sekret
replicationTopology: none
replicas: 3
rollingUpdatePartition: 2
dbConfigMap:
  - name: norepsamplehelm
  directory: cm
```
The replicationTopology variable has a value of none, indicating a non-replicated configuration in which the TimesTen Operator creates one or more non-replicated TimesTen databases, each of which operates independently without replication configured. In addition, the ttclassic chart provides additional variables to assist in your customizations:
- replicas: Determines the number of Pods to be configured. Each Pod contains a TimesTen database. For example, if replicas is 3, there are three Pods each containing a TimesTen database. The default is 1.
- rollingUpdatePartition: Determines how many databases are upgraded. The upgrade procedure is discussed in a later section.
The following customizations apply to both configurations:
- storageClassName and storageSize: Since TimesTen is a database and is persistent, you have to specify a storage class, which is used to request persistent volumes for the database. The storageSize datum determines the amount of storage to be provisioned for TimesTen and its database.
- image: For repository, you must specify the container registry that contains the TimesTen container image. For tag, you specify an image tag. Taken together, image in this example represents the container registry that contains the TimesTen container image along with the image tag representing the release of TimesTen.
- imagePullSecret: You have to specify a Kubernetes Secret that authenticates Kubernetes to pull a TimesTen container image from the specified container registry. You created this Secret in Part 2: Choose a Container Registry for Your Kubernetes Cluster.
- dbConfigMap: Optionally, you can specify one or more ConfigMaps that contain the metadata files for your TimesTen databases. You do not create these ConfigMaps. Rather, the ttclassic chart installation process creates the ConfigMaps for you. How this is done is discussed later in this chapter.

There are many more customizations available to you. See The ttclassic Chart. In addition, the TimesTen Operator provides metadata files that enable you to customize and define the configuration for your TimesTen databases. These files include testUser, db.ini, adminUser, cacheUser, schema,sql, cachegroups.sql, and others. The TimesTen Operator provides several methods for you to make those files available to the TimesTen Operator and TimesTen. For details, see Use Configuration Metadata.