nodejs to redis ECONNRESET error

Question

For our Node.js to Redis connections, we are using the Redis npm module.

Once in a while, we are getting the following error,

message: read ECONNRESET, stack: Error: read ECONNRESET
at exports._errnoException (util.js:1020:11)
at TCP.onread (net.js:568:26)

The Redis setup is, One redis server in intranet and 2 Node js servers each with 8 PM2 instances running in DMZ. There is a Firewall between the node servers and the Redis server.

NODE version - 6.11.2 REDIS version - 3.2.9 PM2 version - 2.4.6

We did the TCP dump as well. The TCP dump shows some RST/ACK packets. TCP Dump

In the nodeJS, we are creating a single redis connection and are trying to use the same redis connection for all requests.

    const Redis = require('redis');
    const Config = require('../../config');
    const Logger = require('../helpers/logger');

    const redisClient = (function() {

       // Start with a fake client so that we have a client that works
       // even when Redis server is down
      let client = {
        get: function(key, callback) {
          callback(null, null);
        },
        setex: function(key, time, value) {
          Logger.info('Value:',value);
          // Do nothing in particular
        }
      };
       // Attempt to create a new instance of an actual redis client
      const redisConfig = Config.get('/redis');
      const tempClient = Redis.createClient(redisConfig.port,redisConfig.host, {
        //eslint-disable-next-line
        // console.log('[redis]','Creating the retry strategy');
        retry_strategy: function(options) { //eslint-disable-line
          //eslint-disable-next-line
          console.log('[redis]','Creating the retry strategy');
          if (options.error && options.error.code === 'ECONNREFUSED') {
              // End reconnecting on a specific error and flush all commands with
              // a individual error
            //eslint-disable-next-line
            console.log('[redis,error]','Connection refused error');
            return new Error('The server refused the connection');
          }
          if (options.error && options.error.code === 'NR_CLOSED') {
            //eslint-disable-next-line
            console.log('[redis,error]','Connection closed error');
            return new Error('The server closed the connection');
          }
          if (options.attempt > 5) {
              // End reconnecting with built in error
            //eslint-disable-next-line
            console.log('Exceeded attempts');
            return undefined;
          }
          if (options.total_retry_time > 1000 * 60 * 60) {
            // End reconnecting after a specific timeout and flush all commands
            // with a individual error
            //eslint-disable-next-line
            console.log('Retrial time:' + options.total_retry_time);
            return 1000;
          }
          // reconnect after
          return Math.min(options.attempt * 100, 3000);
        }
      });

       // Set the "client" variable to the actual redis client instance
       // once a connection is established with the Redis server
      tempClient.on('ready', () => {
        client = tempClient;
      });
      tempClient.on('error', (error) => {
        Logger.info(['redis','error'],'Redis client error:', error);
        if (error.code === 'NR_CLOSED') {
          tempClient.end();
          client = Redis.createClient(redisConfig.port,redisConfig.host, {
            retry_strategy: function(options) { //eslint-disable-line
              if (options.error && options.error.code === 'NR_CLOSED') {
                Logger.info(['redis','error'],'Connection closed error');
                return new Error('The server refused the connection');
              }
            }
          });
        }
      });

       /**
        * Get a redis client
        * @return {Object} client - eventually a proper redis client object
        * (if redis is up) or a fake client object (if redis is down)
        */
      const getClient = function() {
        Logger.info('Getting the client ' + client);
        return client;
      };

      return {
        getClient: getClient
      };

    }());

    module.exports = redisClient;

We would like to know on what exactly is causing the connection issues and why and what is the resolution.

Answer 1

in the /etc/redis/redis.conf file ,

Replace bind 127.0.0.1 with bind 0.0.0.0 Replace protected-mode yes with protected-mode no

and then Allow port 6379 using ufw allow 6379 and ufw allow 6379/tcp

iptables -A INPUT -p tcp --dport 6379 -j ACCEPT iptables -A INPUT -p udp --dport 6379 -j ACCEPT

finally

sudo systemctl stop redis sudo systemctl start redis