Is the testnet centralized? Like is there a foundation that maintains the testnet nodes? Or is it just a lot of people who want to support testing?
- "Kovan is a new testnet for Ethereum using Parity's Proof of Authority consensus engine": https://github.com/kovan-testnet/proposal
- Ropsten public testnet with Proof of Work consensus: https://github.com/ethereum/ropsten
- Rinkeby is a cross-client Proof-of-authority testnet supported by the ethereum foundation: https://github.com/ethereum/EIPs/issues/225
if you go give a look at the config file of geth https://github.com/ethereum/go-ethereum/blob/master/params/config.go.
- at line 34,
chainId is 1refers to the mainnet
- at line 49,
chainId is 3refers to ropsten testnet
- at line 64,
chainId is 4refers to rinkeby testnet
to access kovan, you need the parity client.
Those public testnets are the initiative of the ethereum foundation or the parity team. But everyone is free to join (by that I mean running a mining node to help supporting the testnet). However as the coins (test-ether) on those network do not have any value there is no economic incentive to run a node. So those networks are mainly maintained by the developer teams and some enthusiasts