Prevent accidental change of network-key for active authorities (#3852)
As discovered during investigation of https://github.com/paritytech/polkadot-sdk/issues/3314 and https://github.com/paritytech/polkadot-sdk/issues/3673 there are active validators which accidentally might change their network key during restart, that's not a safe operation when you are in the active set because of distributed nature of DHT, so the old records would still exist in the network until they expire 36h, so unless they have a good reason validators should avoid changing their key when they restart their nodes. There is an effort in parallel to improve this situation https://github.com/paritytech/polkadot-sdk/pull/3786, but those changes are way more intrusive and will need more rigorous testing, additionally they will reduce the time to less than 36h, but the propagation won't be instant anyway, so not changing your network during restart should be the safest way to run your node, unless you have a really good reason to change it. ## Proposal 1. Do not auto-generate the network if the network file does not exist in the provided path. Nodes where the key file does not exist will get the following error: ``` Error: 0: Starting an authorithy without network key in /home/alexggh/.local/share/polkadot/chains/ksmcc3/network/secret_ed25519. This is not a safe operation because the old identity still lives in the dht for 36 hours. Because of it your node might suffer from not being properly connected to other nodes for validation purposes. If it is the first time running your node you could use one of the following methods. 1. Pass --unsafe-force-node-key-generation and make sure you remove it for subsequent node restarts 2. Separetly generate the key with: polkadot key generate-node-key --file <YOUR_PATH_TO_NODE_KEY> ``` 2. Add an explicit parameters for nodes that do want to change their network despite the warnings or if they run the node for the first time. `--unsafe-force-node-key-generation` 3. For `polkadot key generate-node-key` add two new mutually exclusive parameters `base_path` and `default_base_path` to help with the key generation in the same path the polkadot main command would expect it. 4. Modify the installation scripts to auto-generate a key in default path if one was not present already there, this should help with making the executable work out of the box after an instalation. ## Notes Nodes that do not have already the key persisted will fail to start after this change, however I do consider that better than the current situation where they start but they silently hide that they might not be properly connected to their peers. ## TODO - [x] Make sure only nodes that are authorities on producation chains will be affected by this restrictions. - [x] Proper PRDOC, to make sure node operators are aware this is coming. --------- Signed-off-by: Alexandru Gheorghe <[email protected]> Co-authored-by: Dmitry Markin <[email protected]> Co-authored-by: s0me0ne-unkn0wn <[email protected]> Co-authored-by: Bastian Köcher <[email protected]>
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