This tutorial aims at transferring all the data from a remote Redis database (from another provider) to a Redis instance provisioned through the Scalingo Redis Addon.

Requirements

The remote Redis instance should be accessible on the Internet.

These instructions require Redis Input/Output Tools (RIOT) to be installed. This is a set of tools developed by the Redis team. The installation instructions are available on this page.

Install RIOT in a One-Off Container

You first need to install RIOT in a one-off container of your application. RIOT needs a Java Runtime Environment (JRE) to work. When JRE and RIOT are installed, we can replicate the Redis running on an external server:

$ scalingo --app my-app run bash
[00:00] Scalingo ~ $ wget https://github.com/redis-developer/riot/releases/latest/download/riot-redis-$(wget -q --output-document=- https://github.com/redis-developer/riot/releases/latest/download/VERSION).zip
[00:00] Scalingo ~ $ unzip riot-redis*.zip
[00:00] Scalingo ~ $ git clone https://github.com/Scalingo/buildpack-jvm-common.git
[00:00] Scalingo ~ $ echo "java.runtime.version=15" > system.properties
[00:00] Scalingo ~ $ ./buildpack-jvm-common/bin/compile /app
[00:00] Scalingo ~ $ export PATH=$PATH:/app/.jdk/bin/
[00:00] Scalingo ~ $ ./riot-redis-*/bin/riot-redis --uri $SCALINGO_REDIS_URL replicate --uri $REDIS_SOURCE_URL

The REDIS_SOURCE_URL variable must contain the connection string to the external Redis instance. For Redis URI syntax see here.

At that point, the replication process has started. Its duration is relative to the amount of data contained on the remote database. It’s usually a matter of seconds.

Note that the riot-redis tool is powerful and includes various arguments. All the information is on the documentation page. You may want to have a look at the --mode live option for continuous replication. It could be useful for a 0-downtime migration.