Docker deployment

Introduction#

Docker is a very popular container solution being used widely for deploying code in production environments. It makes it easier to Manage and Scale web-applications and microservices.

Remarks#

This document assumes that docker is installed and the daemon running. You can refer to Docker installation to check on how to install the same.

Get docker image for php

In order to deploy the application on docker, first we need to get the image from registry.

docker pull php

This will get you the latest version of image from official php repository. Generally speaking, PHP is usually used to deploy web-applications so we need an http server to go with the image. php:7.0-apache image comes pre-installed with apache to make deployment hastle free.

Writing dockerfile

Dockerfile is used to configure the custom image that we will be building with the web-application codes. Create a new file Dockerfile in the root folder of project and then put the following contents in the same

FROM php:7.0-apache
COPY /etc/php/php.ini /usr/local/etc/php/
COPY . /var/www/html/
EXPOSE 80

The first line is pretty straight forward and is used to describe which image should be used to build out new image. The same could be changed to any other specific version of PHP from the registry.

Second line is simply to upload php.ini file to our image. You can always change that file to some other custom file location.

The third line would copy the codes in current directory to /var/www/html which is our webroot. Remember /var/www/html inside the image.

The last line would simply open up port 80 inside the docker container.

Ignoring files

In some instances there might be some files that you don’t want on server like environment configuration etc. Let us assume that we have our environment in .env. Now in order to ignore this file, we can simply add it to .dockerignore in the root folder of our codebase.

Building image

Building image is not something specific to php, but in order to build the image that we described above, we can simply use

docker build -t <Image name> .

Once the image is built, you can verify the same using

docker images

Which would list out all the images installed in your system.

Starting application container

Once we have an image ready, we can start and serve the same. In order to create a container from the image, use

docker run -p 80:80 -d <Image name>

In the command above -p 80:80 would forward port 80 of your server to port 80 of the container. The flag -d tells that the container should run as background job. The final specifies which image should be used to build the container.

Checking container

In order to check running containers, simply use

docker ps

This will list out all the containers running on docker daemon.

Application logs

Logs are very important to debug the application. In order to check on them use

docker logs <Container id>