Overview

This charm provides a way to deploy a NATS core cluster.

Current features:

• installation of nats-server via a snap (either from the store or a resource);
• clustering with route URLs automatically added to the config of each unit;
• debug options.

TLS support is currently WIP but a cluster with a single certificate and key for all units is possible to configure via the relevant config options.

Clustering Notes

• NATS core does not have message persistence so leadership is not used for ordering of addition of units to the cluster - they come up as they are added and for a full mesh;
• Route URLs are added to all other peers on each unit so that there is no dependency on a particular unit for discovering others;
• Official NATS clients are multi-endpoint aware and will attempt to connect to a random NATS server and find the one that is alive so there is no need for a cluster virtual IP. Therefore, different NATS units can be in different subnets and are not tied to a shared L2 domain.

Deploy

From the Charm Store:

juju deploy cs:~dmitriis/nats-9

juju deploy --resource nats=<path-to-nats-snap-file> <nats-charm-dir>

Debug

juju config nats debug=true trace=true
juju ssh --unit nats/0
journalctl -f -u snap.nats.server.service