Question about Volumes and Images Updates


I am currently using two images - the official Nginx image and my own image which is based on Wordpress’s official php-fpm image. My custom image simply adds custom themes and plugins to the same path as the wordpress core files. In my deployment (using Docker Swarm) I create a volume at /var/www/html so the Nginx container can access the Wordpress files. The problem I’m having is that whenever I make a update to the Wordpress image that involves the files being shared in the volume none of the updates seem to actually take effect. I’ve read in various topics across the internet that changes in an image will not affect a volume, where is this documented? I have seen numerous references to this page: but I do not see this issue stated. Maybe I’m missing it? Can someone point out to me where this issue is mentioned?

Thank you in advance.

Please get into a Shell in your Wordpress image and try to write to your volume and see if it succeeds as a part of troubleshooting.