Shuffling node memberships of subnets: an exploratory conversation

[Lorimer]

@timo

• How often does it happen that a node degrades and needs to be replaced? We must have some data from the past.
• When a node is replaced then isn’t it replaced by a different node of the same provider?
• If it has to be replaced by a node from a different provider then how is the new provider chosen? Randomly?
• How is it decided which providers have spare nodes? Can a provider do anything to increase his probability of having spare nodes, and thereby increase his chances of being selected as the replacement for a degraded node?

• It’s not infrequent that nodes go offline and degraded. Most weeks there are a bunch of proposals to replace these sorts of nodes with healthy nodes (for numerous subnets).
• There are no constraints that enforce a node is replaced by another node from the same node provider. This can’t be expected to be possible I’m afraid. The recent situation with DFINITY-controlled node scarcity is an example. The IC Target Topology simply needs to be satisfied by the selection (but even that’s not always possible, which is also demonstrated by the example linked above).
• Anyone can submit a proposal, so secondary selection criteria (and/or any randomisation) is not controlled/guaranteed.
• Numerous factors can affect the chances of an NP having spare nodes. They can influence this themself by intentionally degrading their nodes to encourage them to be removed from a subnet (at which point they become available for other subnets, as long as they’re no longer degraded).