Checking my eth validator's sync committee duties

Avoid missing extra ETH income and get rewarded for 24hours of sync committee duties.

⏩ Quick steps guide

The following steps align with our mainnet guide. You may need to adjust file names and directory locations where appropriate. The core concepts remain the same.

🗡️ Why do I want to check my sync committee duties ?

• Since the Altair Hard Fork, checking sync committee membership is a must before performing any maintenance. This will give you up to ~27 hours of advanced notice in case your validators have been selected for sync committee duties.

• Understanding the schedule of your validator's duties better, you can find the best time to plan consensus/execution client updates, system reboots or outages.

🤖 Pre-requisites

• Linux bash shell or command line

• Assumes you will be running this script on the beacon node. If running remotely, you might need to change your beacon node's http API to bind from localhost to 0.0.0.0

• Your ETH validator index number(s) -- Enter your validator's public key on https://beaconcha.in/ or https://beaconscan.com/ Example of Validator index # 12345 is shown below.

Given your validator's public key, the index number is shown. Example of Validator 12345 from https://beaconcha.in/validator/12345

✨ Kudos to 2038 on Reddit for authoring this process.

🚧 How to Check Sync Committee Duties script

1. Create a check_sync_committee.sh script with a text editor, nano.

nano check_sync_committee.sh

2. Paste the following script content and then save your file. CTRL+O, enter, then CTRL+X.

#!/bin/sh

BEACON_NODE="http://localhost:5052"
VALIDATOR_LIST=$(echo "$@" | tr ' ' '|')

epoch_to_time(){
    expr 1606824000 + \( $1 \* 384 \)
    }

time_to_epoch(){
    expr \( $1 - 1606824000 \) / 384
    }

get_committee(){
    URLSTEM="${BEACON_NODE}/eth/v1/beacon/states/finalized"
    curl -X GET "${URLSTEM}/sync_committees?epoch=$1" 2> /dev/null \
    | sed -e 's/["]/''/g' | cut -d'[' -f2 | cut -d']' -f1 | tr ',' '\n'
    }

search_committee(){
    get_committee $2 | grep -Ex $VALIDATOR_LIST \
    | awk -v c=$1 '{print "validator:", $1, "found in", c, "sync committee"}'
    }

display_epoch(){
    echo "epoch: $1 : $(date -d@$(epoch_to_time $1)) <-- $2"
    }

CURR_EPOCH=$(time_to_epoch $(date +%s))
CURR_START_EPOCH=`expr \( $CURR_EPOCH / 256 \) \* 256`
NEXT_START_EPOCH=`expr $CURR_START_EPOCH + 256`
NEXTB1_START_EPOCH=`expr $NEXT_START_EPOCH + 256`

echo
display_epoch $CURR_START_EPOCH   "current sync committee start"
display_epoch $CURR_EPOCH         "now"
display_epoch $NEXT_START_EPOCH   "next sync committee start"
display_epoch $NEXTB1_START_EPOCH "next-but-one sync committee start"
echo

if [ "$#" -gt 0 ]
then
    search_committee "current" $CURR_EPOCH
    search_committee "next"    $NEXT_START_EPOCH
fi

3. Add execute permissions to the script.

 chmod +x check_sync_committee.sh

4. Enter your validator index numbers as parameters to the script.

./check_sync_committee.sh <validator index number(s)>
# Example
# ./check_sync_committee.sh 1000 1001 1002 1003

Sample Output of the script:

./check_sync_committee.sh 123511 124216

epoch: 75008 : Sat 30 Oct 21:51:12 BST 2021 <-- current sync committee start
epoch: 75115 : Sun 31 Oct 08:16:00 GMT 2021 <-- now
epoch: 75264 : Mon  1 Nov 00:09:36 GMT 2021 <-- next sync committee start
epoch: 75520 : Tue  2 Nov 03:28:00 GMT 2021 <-- next-but-one sync committee start

validator: 123511 found in current sync committee
validator: 124216 found in next sync committee

This output indicates the following:

• it is currently epoch 75115

• and validator #123511 is in current sync committee from epoch 75008 to epoch 75263

• and validator #124216 is in next sync committee from epoch 75264 to epoch 75520

If there is no output, then no validators are scheduled for current or next sync committee.

❓Troubleshooting:

• The python script calls the http API

• Ensure the http API is enabled for your consensus layer client.

  • teku: --rest-api-enabled=true

• Teku by default uses port 5051, rather than 5052. Replace the port number before using.

  • example: BEACON_NODE="http://localhost:5051"

🔥 Script Usage Caveats:

• Sync committee duties are only known for the current AND next sync committee period.