I have a ruby on rails app running on a Google Cloud Platform VM running on the app engine flexible environment. It looks like it installs most of the software on the VM when I deploy the app with gcloud --project project-name preview app deploy I think it installs rails and other software from reading the temporary dockerfile it creates. It grabs the info for the dockerfile from the app.yaml file (I got this setup from following their tutorials).
This was working fine for me but now I need to install ImageMagick onto the server to manipulate images on the site. Normally you do this by running sudo apt-get install imagemagick from the project directory. When I SSH onto the VM I cant find the project directory so that doesn't work.
I have no idea how to get it to run sudo apt-get install imagemagick each time I make a new deploy to the site so it has the software on the new VM.
As you might be able to tell I'm not very good with the server side of things and want to know what I'm supposed to do to get new software onto the VM the right way so its always there like ruby and rails etc.. are each time I make a new deploy.
You should use a custom Dockerfile when you need additional configuration.
To install ImageMagics you have to set runtime: custom in your app.yaml, create a Dockerfile based on default one, and add following line:
RUN apt-get update && \
apt-get install imagemagick -y
来源：https://stackoverflow.com/questions/39062214/how-to-install-new-software-onto-a-gcp-flexible-environment-vm