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Chapter 3. Migrating from an embedded PostgreSQL 10 database to an external PostgreSQL 10 database
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Before scaling
system.appSpec.replicasto1, the database should be upgraded to the supported version, which is currently PostgreSQL 13. See Red Hat 3scale API Management Supported Configurations - This documentation is about migrating from an embedded PostgreSQL 10 database to an external PostgreSQL 10 database. To upgrade from an external PostgreSQL 10 database to an external PostgreSQL 13 database, you must following the official PostgreSQL documentation.
- Disclaimer: Links contained herein to external website(s) are provided for convenience only. Red Hat has not reviewed the links and is not responsible for the content or its availability. The inclusion of any link to an external website does not imply endorsement by Red Hat of the website or their entities, products or services. You agree that Red Hat is not responsible or liable for any loss or expenses that may result due to your use of (or reliance on) the external site or content.
The process to move from an embedded PostgreSQL database to and external PostgreSQL database should happen with the same DB version. In this migration guide, it should be PostgreSQL 10. You should use external databases for production environments.
If you are using PostgreSQL as your system-database, use the supported version for external database installation with 3scale.
- These steps are general guidelines. Exact steps may vary depending on your operating system, version of PostgreSQL, and specific requirements of your database.
- Read the PostgreSQL documentation and release notes carefully before upgrading.
- Test this procedure in a non-production environment before applying it to a production deployment.
- This process disrupts the provision of the service until the procedure finishes. Due to this disruption, be sure to have a maintenance window.
Procedure
Use APIManager customer resource (CR) to scale down the
system-appDeploymentConfig (DC):apiVersion: apps.3scale.net/v1alpha1 kind: APIManager metadata: name: <apimanager_sample> spec: system: appSpec: replicas: 0 wildcardDomain: <example.com>Verify that the pods are scaled down:
$ oc get deploymentconfig system-app -o jsonpath='{.status.availableReplicas}{"\n"}' 0-
Wait for all the 3scale pods to have the status of
Terminatedbefore proceeding with the PostgreSQL migration.
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Wait for all the 3scale pods to have the status of
Make a backup of the existing PostgreSQL database, including all data, configurations, and user accounts:
$ DB_USER=$(oc get secret system-database -o jsonpath="{.data.DB_USER}" | base64 --decode) $ DATABASE_NAME=$(oc get secret system-database -o jsonpath="{.data.URL}" | base64 --decode | cut -d '/' -f4)ImportantDo not pipe to
stdout. Binary files get corrupted.Dump with custom format:
$ oc rsh $(oc get pods -l 'deploymentConfig=system-postgresql' -o json | jq -r '.items[0].metadata.name') bash -c "pg_dump -U $DB_USER -F c $DATABASE_NAME -f /tmp/<backupfilename>.backup"
Download the backup:
$ oc cp $(oc get pods -l 'deploymentConfig=system-postgresql' -o json | jq -r '.items[0].metadata.name'):/tmp/<backupfilename>.backup <backupfilename>.backup
- Install the same version of PostgreSQL 10 that you deployed on 3scale in your target external system. Download the installation package from the PostgreSQL website following the installation instructions.
- Copy and restore the backup you made of the existing PostgreSQL database, including all data, configurations, and user accounts to the target external system.
Create a new database in PostgreSQL:
$ createdb -U <username> <databasename>
Import the data from the backup file into the new PostgreSQL database.
Restore with custom format:
$ pg_restore [--host <databasehostname>] -U <username> -d <databasename> --verbose -F c <backupfilename>.backup
Verify that the data was successfully imported into the new PostgreSQL database by connecting to the database and running queries:
postgresql://<username>:<password>@<databasehostname>/<databasename>
Update
system-databasesecret:$ oc apply -f - <<EOF --- apiVersion: v1 kind: Secret metadata: name: system-database stringData: DB_PASSWORD: <password> DB_USER: <username> URL: "postgresql://<username>:<password>@<databasehostname>:<databaseport>/<databasename>" type: Opaque EOF
Update APImanager CR to enable external database and scale up system:
$ oc patch apimanager <apimanager_sample> --type=merge --patch '{"spec": {"system": {"database": null, "appSpec": {"replicas": 1}}, "externalComponents": {"system": {"database": true}}}}'Remove local postgresql deployment:
$ oc delete service system-postgresql $ oc delete deploymentconfig system-postgresql $ oc delete pvc postgresql-data
Verify that the pods are scaled up:
$ oc wait --for=condition=available apimanager/<apimanager_sample> --timeout=-1s
Additional resources
