For Tyk for Enterprise On-prem, I believe the configuration metadata for the Tyk cluster is stored in MongoDB. In circumstances where the whole MongoDB cluster is down for a period of time (eg. DBA deleted a critical MongoDB collection by accident), can Tyk servers in the Cluster still start-up and function correctly even if they can’t reach MongoDB for the configuration metadata?
The Dashboard currently depends on MongoDB and though there are long-term plans to eventually remove this dependency, for the time being, it won’t be possible to compile the Dashboard whilst your MongoDB server is down.
Tyk gateways, when configured to be part of a Multi Data Center Bridge (MDCB) configuration (this is an enterprise component), will continue to serve traffic to known clients even if a scaling event occurs while back-end (Dashboard, mongo, master redis keystore) are down. A scaling event would essentially cause a “dumb” gateway to start, and if it cannot reach the back-end it will pull the last good configuration from the local redis cache.
MDCB encourages the use of many slaved gateway clusters with localised redis caches served my a master mongo/redis/Dashboard system that is the ultimate configuration source.
This is the most resilient configuration available.
A standard Pro installation will not do this - it will require a dashboard and mongo instance to be available for a new gateway to start,