High Availability

[lachlan2k]

This issue is to discuss the ins-and-outs of making a highly-available Wag.

In general, it would be nice to have the ability to have Wag running on 2 different servers, for a highly available configuration, so if one server fails (or needs to be shut down), then operation can continue.

Since Wag relies on in-memory maps, it would quite difficult to support to an active-active configuration, so instead, allowing for an active-passive (failover) configuration would be nice.

During a failover condition, users would have to re-auth, but I think that's fine.

The first problem I see is the SQLite database cannot be easily shared, so perhaps one of the first steps could be allowing for other databases (Postgres, MySQL..?)

I don't think it should be Wag's responsibility to direct traffic to the different instances. Instead, the administrator should use features of their networking equipment to perform failover, or use something like keepalived with Vrrp.