Upgrading versions in OpenSearch is often a very daunting task, especially when jumping major versions. Users fear downtime, data loss, configuration issues and more, all of which are legitimate risks when upgrading.
One way to prevent potential issues and upgrade easily is to add a second, new cluster with the updated version and write the data to both clusters in a synchronized manner. Having a mirroring solution in the application itself could be used to mirror data to multiple clusters in different versions and thus avoid downtime.
Another option is to try to restore snapshots from earlier versions in the newer version, but this might fail due for multiple reasons, such as jumping more than one major version, breaking changes or system changes.
If you’re feeling particularly lucky, you can try upgrading nodes in place using rolling restart, but this will likely cause downtime.
The free Opster Management Console (OMC) can be used to upgrade OpenSearch versions automatically without downtime. By using the OMC, you can also deploy multiple clusters, configure node roles, scale cluster resources, manage certificates and more – all from a single interface, for free. Check it out here.
