Teku Zero Sync

Teku now offers a Zero Sync mode that supports validation from a backup Beacon Chain provided by AVADO. Enabling Zero Sync eliminates the need to wait for your Execution Client to sync initially and reduces downtime in case of errors or maintenance.

The Zero Sync mode is not enabled by default. You can enable it by setting the MODE parameter to zerosync in the Management Page of Teku.

1. Navigate to the Management Page of Teku. You can do this by:

   • Clicking the Manage Package button immediately upon installing Teku; or equivalently,

   • Navigating to My Dapps menu, then clicking the Manage button on the Teku Consensus Client line.

2. Locate the section called "Environment Variables".

3. Insert zerosync (all small letters) into the value of the MODE parameter.

4. Click "Update environment variables". Teku will restart.

5. You can now check Teku's status by opening the DApp. With Zero Sync enabled, you will see the status of your local the Zero Sync beacon chains side by side in the header.

When your local chain is in sync, Teku will automatically start using it. You can leave Teku in Zero Sync mode such that, in the event your local Beacon Chain falls out of sync, Teku will automatically switch to the fall back Beacon Chain for continued operations.

If you wish, you can also disable the Zero Sync mode by setting the MODE parameter to standalone in the Management Page of Teku.

Caveats

Note that when using the Zero Sync mode and your local node is not fully synced:

• You cannot exit a validator while your node is relying on the failover server. Your node needs to be synced before you can exit the validator.

• MEV-Boost does not work.

• If you happen to hit a block proposal, an empty block may be produced, with zero block rewards.

The idea of the Zero Sync mode is to help you keep your validators attesting during the initial sync or re-sync of your node. Block production during that time may not work - but consider the alternative of not using Zero Sync and your node was offline, you would miss the block proposal anyway and also miss out on the attestation rewards completely. So although the current setup is not optimal, it's better than being offline.

During the time when Zero Sync mode is active (and your node is still syncing), Teku will periodically report the following error (in red) in the Logs:

Remote Validator Client detected and no default fee recipient has been configured via the validators-proposer-default-fee-recipient option! It is strongly recommended to configure it to avoid possible block production failures in case the node has not been prepared for potential proposers by the Validator Client.

The error message indicates that block production may fail, as explained above.

Once your Beacon Chain and Execution Client are back in sync, Teku will switch back to your local node and work with the MEV-Boost settings you have configured. You may also consider setting the MODE parameter to standalone to make sure Teku uses the local node.