MongoDB Replica Issue

This repo tries to reproduce the Intermittent error: MongoConnectionException:No suitable servers found (serverselectiontryonce set): Server closed connection. calling ismaster on 'x.x.x.x:27017'

This is now fixed with MongoDB PHP Driver 1.4.2 and MongoDB PHP Library 1.3.0 with PHP 7.2.3 and Alpine 3.7!

I can reproduce the error with this setup. You find the logs of a test run in log.txt file.

Why are some requests are successfully and some failed? I guess it's a PHP-FPM static child caching (or even opcache) issue.

With this repo we have a nice playground to investigate this issue further.

Installation

Install Docker >= 1.13 and Docker Compose >= 1.11.

Install now Composer dependencies with

$ docker run --rm -it --volume $(pwd):/app prooph/composer:7.2 install

Run test

The index.php uses two different MongoDB connections.

• One with readPreference=primaryPreferred for inserts
• Second with readPreference=secondaryPreferred for reads

Simply run:

$ . start.sh | tee log.txt

To watch PHP logs in realtime run in another terminal

$ docker-compose logs -f --tail=20 php

You see the output and it is also written to the log.txt file. Search in the log file for MongoConnectionException to find the error.

You can also browse the website http://localhost:8080/.

If the test has finished reload this page some times to see the MongoConnectionException.

Check status manually

To manually check MongoDB Replica Status use one of

$ docker-compose exec mongodb0 sh status.sh
$ docker-compose exec mongodb1 sh status.sh
$ docker-compose exec mongodb2 sh status.sh

Cleanup

Simply run:

$ . down.sh