Hot tip: You can calculate your slot leader schedule, which tells you when it's your stake pools turn to mint a block. This can help you know what time is best to schedule maintenance on your stake pool. It can also help verify your pool is minting blocks correctly when it is your pool's turn. This is to be setup and run on the block producer node.
Since version 1.34, it is possible to check the slot leadership schedule for the current and next epoch using cardano-cli.
Next epoch's leadership schedule becomes available 1.5 days (36 hours) before the end of the current epoch.
Next epoch's leadership schedule is obtained with the following:
SlotNo UTC Time
-------------------------------------------------------------
4073 2021-12-29 17:26:54.998001755 UTC
4126 2021-12-29 17:27:00.298001755 UTC
4206 2021-12-29 17:27:08.298001755 UTC
4256 2021-12-29 17:27:13.298001755 UTC
4309 2021-12-29 17:27:18.598001755 UTC
4376 2021-12-29 17:27:25.298001755 UTC
4423 2021-12-29 17:27:29.998001755 UTC
4433 2021-12-29 17:27:30.998001755 UTC
The automation of this process will work with the following method, as said, next epoch blocks can be checked 1.5 days before the start of the next epoch or at the 75% of the current epoch's completion.
What the script will do, is to calculate the correct day and hour to run the command, then wait until it is possible to do that and once the selected time comes, run the check listed below.
Once finished, it will redirect the output into a log file that can be analyzed.
Keep in mind that running the leadership-schedule command, listed below and used by the script, with the cardano-node at the same time, will use approximately 17GB of RAM at the time of writing this guide (April 2022).
The possible solutions to avoid a node crash are:
Increase the RAM of the node
Create the leaderScheduleCheck.sh script file in the block producer (script can also be run on a relay node but vrf.skey needs to be exported there) and paste the following code inside of it:
#!/bin/bash
# cardano node directory
DIRECTORY=
if [[ ! -d "$DIRECTORY/logs" ]]; then mkdir $DIRECTORY/logs; fi
# create a pid, this way you can ps aux | grep leaderScheduleCheck.sh to see if script is running
echo $$ > "$DIRECTORY/logs/leaderScheduleCheck.pid";
# Set your own stake pool ID
STAKE_POOL_ID=""
TESTNET="testnet"
MAINNET="mainnet"
# Set the network magic value as needed for the testnet environment that you want to use
# For details on available testnet environments, see https://book.world.dev.cardano.org/environments.html
MAGICNUMBER="1"
# Edit variable with $TESTNET for Testnet and $MAINNET for Mainnet
network=$TESTNET
# check for vrf.skey presence
if [[ ! -f "$DIRECTORY/vrf.skey" ]]; then echo "vrf.skey not found"; exit 127; fi
CCLI=$(which cardano-cli)
if [[ -z $CCLI ]]; then echo "cardano-cli command cannot be found, exiting..."; exit 127; fi
JQ=$(which jq)
if [[ -z $JQ ]]; then echo "jq command cannot be found, exiting..."; exit 127; fi
read -ra BYRON_GENESIS <<< "$(jq -r '[ .startTime, .protocolConsts.k, .blockVersionData.slotDuration ] |@tsv' < $DIRECTORY/$network-byron-genesis.json)"
if [[ -z $BYRON_GENESIS ]]; then echo "BYRON GENESIS config file not loaded correctly"; exit 127; fi
network_magic=""
if [ $network = $TESTNET ]; then
network_magic="--testnet-magic $MAGICNUMBER"
elif [ $network = $MAINNET ]; then
network_magic="--mainnet"
else
echo "Incorrect network selected, please use $TESTNET or $MAINNET network type"; exit 1
fi
# Check that node is synced
function isSynced(){
isSynced=false
sync_progress=$($CCLI query tip $network_magic | jq -r ".syncProgress")
if [[ $sync_progress == "100.00" ]]; then
isSynced=true
fi
echo $isSynced
}
# Get current epoch
function getCurrentEpoch(){
echo $($CCLI query tip $network_magic | jq -r ".epoch")
}
# Get epoch start time based on current one
function getEpochStartTime(){
byron_genesis_start_time=${BYRON_GENESIS[0]}
byron_k=${BYRON_GENESIS[1]}
byron_epoch_length=$(( 10 * byron_k ))
byron_slot_length=${BYRON_GENESIS[2]}
echo $(( $byron_genesis_start_time + (($(getCurrentEpoch) * $byron_epoch_length * $byron_slot_length) / 1000) ))
}
# Get epoch end time based on the current one
function getEpochEndTime(){
#calculate currentEpoch Start time + 5 days of epoch duration - 10 minutes(600s) to not overlap with next epoch
echo $(( $(getEpochStartTime)+(5*86400)-(600) ))
}
# Get current timestamp
function getCurrentTime(){
echo $(printf '%(%s)T\n' -1)
}
# Convert timestamps to UTC time
function timestampToUTC(){
timestamp=$1
echo $(date +"%D %T" -ud @$timestamp)
}
# Find the correct time to run the leaderslot check command
function getLeaderslotCheckTime(){
epochStartTime=$(getEpochStartTime)
epochEndTime=$(getEpochEndTime)
# epoch completion percent to check for --next epoch leaderslots
percentage=75
checkTimestamp=$(( $epochStartTime+($percentage*($epochEndTime-$epochStartTime)/100) ))
echo $checkTimestamp
}
# Function to make the script sleep until check need to be executed
function sleepUntil(){
sleepSeconds=$1
if [[ $sleepSeconds -gt 0 ]]; then
echo "Script is going to sleep for: $sleepSeconds seconds"
sleep $sleepSeconds
fi
}
# Check leaderschedule of next epoch
function checkLeadershipSchedule(){
next_epoch=$(( $(getCurrentEpoch)+1 ))
currentTime=$(getCurrentTime)
echo "Check is running at: $(timestampToUTC $currentTime) for epoch: $next_epoch"
$CCLI query leadership-schedule $network_magic --genesis "$DIRECTORY/$network-shelley-genesis.json" --stake-pool-id $STAKE_POOL_ID --vrf-signing-key-file "$DIRECTORY/vrf.skey" --next > "$DIRECTORY/logs/leaderSchedule_$next_epoch.txt"
}
if [ isSynced ];then
echo "Current epoch: $(getCurrentEpoch)"
epochStartTimestamp=$(getEpochStartTime)
echo "Epoch start time: $(timestampToUTC $epochStartTimestamp)"
epochEndTimestamp=$(getEpochEndTime)
echo "Epoch end time: $(timestampToUTC $epochEndTimestamp)"
currentTime=$(getCurrentTime)
echo "Current cron execution time: $(timestampToUTC $currentTime)"
timestampCheckLeaders=$(getLeaderslotCheckTime)
echo "Next check time: $(timestampToUTC $timestampCheckLeaders)"
timeDifference=$(( $timestampCheckLeaders-$currentTime ))
if [ -f "$DIRECTORY/logs/leaderSchedule_$(( $(getCurrentEpoch)+1 )).txt" ]; then
echo "Check already done, check logs for results"; exit 1
elif [[ $timeDifference -gt 86400 ]]; then
echo "Too early to run the script, wait for next cron scheduled job"; exit 1
elif [[ $timeDifference -gt 0 ]] && [[ $timeDifference -le 86400 ]]; then
sleepUntil $timeDifference
echo "Check is starting on $(timestampToUTC $(getCurrentTime))"
checkLeadershipSchedule
echo "Script ended, schedule logged inside file: leaderSchedule_$(( $(getCurrentEpoch)+1 )).txt"
elif [[ $timeDifference -lt 0 ]] && [ ! -f "$DIRECTORY/logs/leaderSchedule_$(( $(getCurrentEpoch)+1 )).txt" ]; then
echo "Check is starting on $(timestampToUTC $(getCurrentTime))"
checkLeadershipSchedule
echo "Script ended, schedule logged inside file: leaderSchedule_$(( $(getCurrentEpoch)+1 )).txt"
else
echo "There were problems on running the script, check that everything is working fine"; exit 1
fi
else
echo "Node not fully synced."; exit 1
fi
Set the following variables with your data:
# cardano node directory, directory where all files needed for running a cardano-node are located
DIRECTORY=
# Set your own stake pool ID
STAKE_POOL_ID=""
# Set variable with $TESTNET for Testnet and $MAINNET for Mainnet
network=
Add execution permissions and test that the script is running without errors:
If everything is working correctly, an output as the follow will be presented:
Current epoch: 199
Epoch start time: 04/14/22 20:20:16
Epoch end time: 04/19/22 20:10:16
Current cron execution time: 04/18/22 15:37:51
Next check time: 04/18/22 14:12:46
[...] Cutted output cause it can vary based on time when the script is ran
Configure Cronjob to make the script run automatically:
To configure the job at the start of an epoch, keep in mind the following information:
Epoch in MAINNET starts at 21:45 UTC
Find the time when the cronjob should start:
Cronjobs run based on local timezone, not on UTC hours. \
Find timezone:
timedatectl | grep "Time zone"
Once you found your timezone, you need to understand when run the job (It isn't mandatory to run it at epoch's starting hour).
Here is an example with a UTC+2 timezone for Mainnet:
Epoch starting hour UTC: 21:45 Epoch starting hour for requested timezone: 23:45 Cronjob will be set to run at 23:45
Add cronjob and edit parameters based on your needs, PATH, NODE_HOME, NODE_CONFIG, CARDANO_NODE_SOCKET_PATH, MM, HH, path_to_script and desired_log_folder:
cat > $NODE_HOME/crontab-fragment.txt << EOF
# disable MTA use
MAILTO=""
# linux path, needed because cron doesn't know where to find cardano-cli
PATH=
# folder with cardano-node files
NODE_HOME=
# testnet or mainnet
NODE_CONFIG=
# path to the socket of cardano node, should be under db/ folder under NODE_HOME
CARDANO_NODE_SOCKET_PATH=
MM HH * * * path_to_script/leaderScheduleCheck.sh > desired_log_folder/leaderSchedule_logs.txt 2>&1
EOF
crontab -l | cat - ${NODE_HOME}/crontab-fragment.txt > ${NODE_HOME}/crontab.txt && crontab ${NODE_HOME}/crontab.txt
rm ${NODE_HOME}/crontab-fragment.txt
Once the cronjob is set, the script will be run every day and it will check if in the next 24H, it will be the correct time to run the command and see if there are scheduled blocks in the next epoch.
For every epoch, there will be a file called leaderSchedule_epoch.txt
A community-based cardano-node CLI tool. It's a collection of utilities to enhance and extend beyond those available with cardano-cli.
The number of slots in which your stake pool is currently elected to mint blocks
To send data to PoolTool using CNCLI utilities without using the cncli.sh script, create a configuration file containing your PoolTool API key and stake pool details.
To create a configuration file, update values in the following example with your pool information. To follow the example, save the configuration file at $NODE_HOME/scripts/pooltool.json
cat > ${NODE_HOME}/scripts/pooltool.json << EOF
{
"api_key": "<UPDATE WITH YOUR API KEY FROM POOLTOOL PROFILE PAGE>",
"pools": [
{
"name": "<UPDATE TO MY POOL TICKER>",
"pool_id": "$(cat ${NODE_HOME}/stakepoolid.txt)",
"host" : "127.0.0.1",
"port": 6000
}
]
}
EOF
Creating systemd Services
CNCLI sync and sendtip can be easily enabled as systemd services. When enabled as systemd services:
sync will continuously keep the cncli.db database synchronized.
sendtip will continuously send your stake pool tip to PoolTool.
To set up systemd:
Create the following and move to/etc/systemd/system/cncli-sync.service
If your pool is scheduled to mint blocks, you should hopefully see output similar to this. Listed by date and time, this is your slot leader schedule or in other words, when your pool is eligible to mint a block.
Checking leadership log for Epoch 222 [ d Param: 0.6 ]
2020-10-01 00:11:10 ==> Leader for slot 121212, Cumulative epoch blocks: 1
2020-10-01 00:12:22 ==> Leader for slot 131313, Cumulative epoch blocks: 2
2020-10-01 00:19:55 ==> Leader for slot 161212, Cumulative epoch blocks: 3
Your slot leader log should remain confidential. If you share this information publicly, an attacker could use this information to attack your stake pool.
Automate the process with Cronjob:
Credits to for developing the .
by,,
Installing the Binary
Running LeaderLog with stake-snapshot
provides to submit the following data for your stake pool:
The following figure shows the green badge that PoolTool displays next to your stake pool when your node is fully synchronized with the blockchain (image credit to ):
You can also use developed by the Cardano Community to send the block height and slot count to PoolTool.
maintain the companion script to help stake pool operators use the Cardano Community's CNCLI utilities.
For details on requesting an API key from PoolTool, see the topic .
Upgrading CNCLI
Credits for inventing this process goes to the hard work by (developer of JorManager and operator of BCSH family of stake pools).
Clone the leaderLog scripts from git repo.
Official documentation for this LeaderLogs tool can be
Set the timezone name to format the schedule's times properly. Use the --tz option. [Default: America/Los_Angeles]')
Pro Tip: 1.5 days before the end of the current epoch, you can find the next epoch's schedule.
Pro Tip #2: Add the flag --epoch <INTEGER #> to find a specific epoch's slot schedule.
Pro Tip #3: Ensure your slot leader scripts are up to date.
