System update

Automated system update is available from version 0.7.0. Previous versions were unable to update system data. There was only an update of the code. As of version 0.7.0 the system keeps information about the indexes used. In addition, access to data is carried out using aliases, these are indicators for data, something reminiscent of symbolic links.

The update process

When upgrading, Tracardi leaves the old version indexes unchanged and only marks them as the previous version (aliases to these indexes have the .prev suffix).

At the same time, new empty indexes are created along with new aliases. Then, if the schema of the old index has not changed, the data pointer is switched from the old index to the new one. If the scheme has changed, the data is migrated using a script that rewrites the data between indexes and copies the data from the old fields to the new ones, respectively.

Prerequisites

However, it is important to only install dockers with a tagged version. The latest version may contain incorrect data, which may result in the loss of continuity of updates. As a result, it may be difficult to update the system.

Installation of version 0.7.0

As it was said above the versions prior to 0.7.0 are not aware of previous data schemas. Therefore, the system does not know what indexes were used previously and it is not able to check the changes that have occurred in their schemas. That means, the manual data migration by re-indexing is necessary. If the collected data in previous versions is not important and it is possible to lose it, we recommend a fresh install.

Manual transfer

To transfer data, first check what indexes you have in elasticsearch. This can be done by going to Monitoring / Elasticsearch indices in Tracardi. Indexes marked Connected are currently in use and are prefixed with a version number. Old indexes from system e.g. version 0.6.0, do not have a prefix and are marked as Not Connected.

To transfer data, use the reindex function available in elasticsearch. Documentation of this functionality can be found here.

https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-reindex.html

Reindexing data is nothing more than copying it from one index to another.