At the ETHBerlin back in September, a team of hackers from ChainSafe, along with Parity's Afri Schoedon, began work on Görli, a universal proof-of-authority testnet for Ethereum developers. Following the hackathon, a call for participation, written by Schoedon, was posted across GitHub and Twitter. In the proposal, Schoedon cited the lack of "consistent availability and high reliability" among existing cross-client testnets. The hope is that Görli might fill this void.
Now, just over two months later, the testnet is up and going. There are still bugs to be worked out, and the GitHub README is calling it "pre-testnet v0.2," warning that "it might break any time."
Over the weekend there were some hiccups with Parity node compatibility, and some moments when the testnet was down due to issues with validators being offline, preventing the remaining validators from reaching consensus around two conflicting blocks. For the moment though, things appear to be trucking along fairly smoothly at the speed of roughly one block every 13 seconds.
Still, at this stage of development issues like the ones over the weekend are more helpful than concerning. Schoedon told ETHNews, "Görli is the first proof-of-authority network that is working across different clients written in different languages by different developers. So, each issue we discover helps improving the client's engines and the Clique POA protocol."
Back in September when developments were first being made, there was some debate around which consensus engine should be used. Geth's native testnet is Rinkeby, which uses Clique. Parity's native testnet is Kovan, which uses Aura. In the end, it was decided to just do both and allow for two cross-client PoA testnets.
Despite the prominence of Parity's Schoedon in this project, Görli uses the Clique engine. This explains the difficulties Parity's client is facing, but in any case, the team appears to be on it. Once these bugs are worked out, they'll begin working on a Go implementation of Aura in Geth. It's unclear what that testnet would be called.
For now, Görli is usable by Geth, Pantheon, and Nethermind – or any client supporting the Clique engine. An official launch is expected some time later, perhaps January, after bugs are worked out and there is an established and reliable validator set.