Geth + Lighthouse kubernetes deployment on GKE

A Kubernetes project to deploy a PoS Ethereum full node on Google GKE using a Geth "execution layer" and a Lighthouse "consensus layer".

This architecture ca be deployed running the cloudbuild.yaml file from a Google cloudbuild console.

InfluxDB

Geth can be instructed to send operational metrics to an InfluxDB instance.

After deploying InfluxDB, connect to the pod and create a database and a user INFLUX_DB_USERNAME with password INFLUX_DB_PASSWORD. Keep these data in a safe place.

kubectl get pods

# Obtain something like this
NAME                                     READY   STATUS    RESTARTS      AGE
geth-deployment-7f74d4fb96-tlhhg         1/1     Running   0             42h
influxdb-deployment-0                    1/1     Running   0             42h
lighthouse-deployment-6fbc98c8b8-p89x6   1/1     Running   0             42h
nginx-deployment-7c776cbc96-f2lnw        1/1     Running   0             42h

# Obtain an InfluxDB shell
kubectl exec -it influxdb-deployment-0 bin/bash

# Run `influx`
root@influxdb-deployment-0: influx

# The InfluxDB cli will show up
Connected to http://localhost:8086 version 1.8.10
InfluxDB shell version: 1.8.10
> 

You can now issue the following commands to create a database for geth with username and password.

CREATE DATABASE "geth"
USE geth
CREATE USER "<INFLUX_DB_USERNAME>" WITH PASSWORD '<INFLUX_DB_PASSWORD>'
GRANT ALL ON "geth" TO "user"

Same credentials must be configured on the cloudbuild trigger as variables _INFLUX_DB_USERNAME, _INFLUX_DB_PASSWORD.

In order to collect geth metrics you need to enable corresponding lines in the the ./geth/deployments/geth-deployment.yaml.

# Enable the following lines to collect metrics on InfluxDB
 - "--metrics"
 - "--metrics.influxdb=true"
 - "--metrics.influxdb.endpoint=http://influxdb-service:8086"
 - "--metrics.influxdb.username=$(INFLUX_DB_USERNAME)"
 - "--metrics.influxdb.password=$(INFLUX_DB_PASSWORD)"
 - "--metrics.influxdb.database=geth"

Expose the node

You can expose your node deploying the nginx pod. All the required configuration can be found under the ./nginx folder. The current configuration exposes:

• Geth RPC Http
• Geth RPC WebSocket
• Influx DB

Nginx can be deployed running the ./nginx/cloudbuild.yaml file from a Google cloudbuild console.

Track synchronization status

Despite InfluxDB metrics allow to monitor the node status, Geth is not built to track metrics on the current sync status. We can achieve this connecting to the node IPC channel.

kubectl get pods

# Obtain something like this
NAME                                     READY   STATUS    RESTARTS      AGE
geth-deployment-7f74d4fb96-tlhhg         1/1     Running   0             42h
...

# Obtain a shell on Geth
kubectl exec -it geth-deployment-7f74d4fb96-tlhhg bin/sh

# Connect to the node IPC
root@geth-deployment-7f74d4fb96-tlhhg: geth attach var/geth/geth.ipc

Now you are connected the node IPC JavaScript console. Paste the following code to poll the synchronization status.

function syncStatus(currentBlock, highestBlock) {    
    return {
        percentage: ((currentBlock/highestBlock) * 100).toFixed(4),
        blocksLeft: highestBlock - currentBlock
    }
}

setInterval(() => {
   let s = syncStatus(eth.syncing.currentBlock, eth.syncing.highestBlock);
   console.log(`${s.percentage}% (blocks left ${s.blocksLeft})`);
}, 1000);