> The HA is a bit murky. I downed two of my three nodes and the cluster collapsed. Since Flynn runs on one machine I expected it to work
I'd expect this is by design. In a 3-node system that takes CP out of the CAP theorem (consistency over availability), you can only lose one node before the system becomes unavailable. This is because, as far as the remaining node knows, the other two nodes could still be up but network partitioned off from it. To prevent a split brain in such a scenario, you need a majority of nodes to be accessible or else they'll intentionally stop working.
tl;dr: A 3-node cluster with 2 nodes down is not the same thing as a 1-node cluster.
I'd expect this is by design. In a 3-node system that takes CP out of the CAP theorem (consistency over availability), you can only lose one node before the system becomes unavailable. This is because, as far as the remaining node knows, the other two nodes could still be up but network partitioned off from it. To prevent a split brain in such a scenario, you need a majority of nodes to be accessible or else they'll intentionally stop working.
tl;dr: A 3-node cluster with 2 nodes down is not the same thing as a 1-node cluster.