Building and pushing an application

We saw earlier that we can also use the docker-compose build command to just build the images of an application defined in the underlying docker-compose file. But to make this work, we’ll have to add the build information to the docker-compose file:

1. Open a new browser window and navigate to the chapter’s folder (ch11):

   $ cd ~/The-Ultimate-Docker-Container-Book/ch11

2. Create a subfolder called step3 and navigate to it:

   $ mkdir step3 && cd step3

3. Copy the docker-compose.yml file from the step2 folder to this new folder:

   $ cp ../step2/docker-compose.yml .

4. Open the copied file and please note the build key for the web service on line 3 in the following screenshot. The value of that key indicates the context or folder where Docker is expecting to find the Dockerfile to build the corresponding image.

Figure 11.21 – The build key in the web service of the docker-compose.yml file

Please...