Docker Troubleshooting

  1. How to Run Multiple Projects by Docker
    1. Multiple Projects - Quick Solution - Only One Project Running at the Time
    2. Multiple Projects - Long Term Solution
  2. Update of Dockerfile is not Reflected
  3. Update of Docker-compose is not Reflected
  4. Docker-sync stopped to sync files
  5. Application is slow on Mac
  6. A docker container is not running
  7. Composer dependencies installation fails on memory limit
  8. Starting up the Docker containers fails due to invalid reference format

If you are developing on Shopsys Framework using docker, you might run into some problems during the process.

Most of the time you might think that a problem is in docker, but the truth is that you are probably using it wrong. This document provides advices that will help you develop Shopsys Framework on docker without problems.

How to Run Multiple Projects by Docker

If you are using docker for more than one Shopsys Framework project, you might run into a problem with container names and their ports. Docker requires to have unique container name and port for each container and since our docker-compose is not dynamically initialized, it contains hard coded container names and ports and that makes running more projects in docker on same machine impossible without modifying your configuration.

With that being said we got two options to solve this problem.

Multiple Projects - Quick Solution - Only One Project Running at the Time

This solution is simpler and is used if we only need one project running at the time.

All we really need to do is to properly turn off docker-compose.

Usually everyone shut off their docker-compose by running docker-compose stop, which is not correct way.

This command is used to stop containers, not to delete them. That means that if you now try to start docker compose in other project, it will output error that there already are containers with that names. That's true because these stopped containers are still registered in memory.

To properly delete your workspace containers, run:

docker-compose down

This will not only stop the containers but it will also delete them. This means, that containers and all their data in volumes will be deleted. Now you can use same configuration in other project and it will work.

Multiple Projects - Long Term Solution

This solution is more viable for someone who really needs to have projects ready to run in a few seconds and often end up having two or more projects running at the same time. So what if we don't want to always reinstall whole containers and we want our data to persist in volumes?

Earlier we said that Docker needs to have unique container names and ports.

So how about changing their name? We recommend to replace shopsys-framework with your project name. For instance, php-fpm conainer that is defaultly named as shopsys-framework-php-fpm would now be named my-project-name-php-fpm.

This would actually work only if you always downed docker-compose before switching between projects. Because it would try to locate our localhost ports to the same value and that would fail.

So we need to change the ports of the containers. Containers have their ports defined in this format

8000:8000

First one defines port exposed on our local computer, second one is for docker network. Since with every start of docker compose docker creates the new network and that isolates each project from each other, we do not need to care about second port. We actually just need to allocate the first port to free port on our local system.

Since we are trying to change ports on your local machine there is a chance that you will pick port that is already allocated for something else running on your computer. You can check all of your taken ports using netstat (for MacOs lsof).

netstat -ltn

This will output all listening TCP ports in numeric format. Now we can just pick one that isn't in this list and set it to our container.

Warning

Try not to use ports between 1000-1100, these are ports that root usually uses for its processes.

So now we got configured our docker-compose files in a way they do not have any conflicts among them. That way we can have as many projects running at the same time as many ports there are in our local network.

Remember that after changing these you need to do few things differently.

  • You changed port of webserver container which affects the domain URL, so you need to change ports in domains_urls.yaml.
  • You changed container_name of php-fpm which means that in order to get inside the php-fpm container you must now use this name. for instance, if your new container name is my-new-project-name-php-fpm you need to execute
docker exec -it my-new-project-name-php-fpm bash

Update of Dockerfile is not Reflected

Sometimes there is need to change the dockerfile for one of our images. If we already had project running once in docker, there is probably cached image for the container.

That means that docker does not really check if there is change in the dockerfile, it will always build container by cached image. So what we actually need is to rebuild our containers. First we need to stop our containers in docker-compose because we cannot update containers that are already in use:

docker-compose stop

Then we need to force Docker to rebuild our containers:

docker-compose build

Docker has now updated our containers and we can continue as usual with:

docker-compose up -d

Update of Docker-compose is not Reflected

Docker compose is much easier to change than images. If we change anything in docker-compose we just need to recreate docker-compose. That is done by executing:

docker-compose up -d --force-recreate

Docker-sync stopped to sync files

Docker-sync suggests (in known issue) to use Docker for Mac in version 17.09.1-ce-mac42 (21090). This version helped most people to solve their issues with syncing.

You may sometimes encounter a sync problem even with the suggested version of Docker. In those cases, you need to recreate docker-sync containers. Here are two easy steps you have to follow:

Delete your docker-sync containers and volumes (data on your host will not be removed):

docker-sync clean

Start docker-sync so your docker-sync containers and volumes will be recreated:

docker-sync start

Application is slow on Mac

We focus on enhancing the performance of the application on all platforms. With Docker for Mac and Docker for Windows there are known some performance issues because of all project files need to be synchronized from host computer to application running in a virtual machine. On Mac, we partially solved this by implementing docker-sync. Docker-sync has some limits and that is the reason why we use Docker native volumes for syncing PostgreSQL and Elasticsearch data to ensure the data persistence. In some cases, performance can be more important than the persistence of the data. In this case, you can increase the performance by deleting these volumes in your docker-compose.yml file but that will result in loss of persistence, which means that the data will be lost after the removal of the container, e.g. during docker-compose down.

A docker container is not running

You can inspect what is wrong by using docker logs <container-name> command.

Composer dependencies installation fails on memory limit

When composer install or composer update fails on an error with exceeding the allowed memory size, you can increase the memory limit by setting COMPOSER_MEMORY_LIMIT environment variable in your docker/php-fpm/Dockerfile or docker-compose.yml.

Note

Since v7.0.0-beta4 we have set the Composer memory limit to -1 (which means unlimited) in the php-fpm's Dockerfile.
If you still encounter memory issues while using Docker for Windows (or Mac), try increasing the limits in Docker -> Preferences… -> Advanced.

Note

Composer dependencies contain 3-rd party software with licenses that are described in document Open Source License Acknowledgements and Third-Party Copyrights

Starting up the Docker containers fails due to invalid reference format

Docker images may fail to build during docker-compose up -d due to invalid reference format, eg.:

Building php-fpm
Step 1/41 : FROM php:7.2-fpm-stretch as base
ERROR: Service 'php-fpm' failed to build: Error parsing reference: "php:7.2-fpm-stretch as base" is not a valid repository/tag: invalid reference format

This is because you have a version of Docker which does not support multi-stage builds.

Upgrade your Docker to version 17.05 or higher and try running the command again.