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keep-alive cron job

Goal​

Keepalive is a script built by the DAO-DAO team which serves to automate ibc client updates, minimizing ibc channel downtimes. This guide will review:

  • how to install your node to run the keepalive scripts
  • how to setup a cronjob service on your computer locally

Alternate Approach​

Go Relayer​

By default, a running instance of go-relayer is able to automatically update clients if the client has less than 1/3 of its trusting period left.

You can choose to update clients more frequently by using the --time-threshold flag when running rly start.

Rust Relayer (Hermes)​

Install Relayer & Keepalive​

The scripts expect to be run in an environment where either hermes or ibc-rly relayer binaries are installed. It may also be useful to run a full node for both chains you expect to relay between locally.

Setup CronJob Locally​

Cron is a time-based job scheduling system. crontab is a special file that holds the schedule of jobs cron will run. You can edit your crontab with the following command:

crontab -e

If this is the first time you’re running the crontab command under this user profile, it will prompt you to select a default text editor to use when editing your crontab:

Output
no crontab for sammy - using an empty one

Select an editor.  To change later, run 'select-editor'.
  1. /bin/nano        <---- easiest
  2. /usr/bin/vim.basic
  3. /usr/bin/vim.tiny
  4. /bin/ed

Choose 1-4 [1]:

When you run crontab -e in the future, it will bring up your crontab in this text editor automatically. Once in the editor, you can input your schedule with each job on a new line. Otherwise, you can save and close the crontab for now (CTRL + X, Y, then ENTER if you selected nano).

Adding Keepalive​

add the following to your crontab file to run the keepalive script every three days.

0 0 */3 * * cd /path/to/polytone-keepalive && npm run keepalive

make sure you then restart your systemd service:

systemctl daemon-reload

References​