A few lines of Kubernetes configuration ... and a custom Docker image, which might tilt the scales of complexity in favor of starting from a stock installation

A few lines of Kubernetes configuration ... and a custom Docker image, which might tilt the scales of complexity in favor of starting from a stock installation of whatever server stack serves the blog and adding content, configuration files, SQL scripts etc. more frugally and explicitly. In particular, how is the blog updated? I don't see how replacing and/or backing up a Docker image could be more convenient than copying files through a SFTP client and using other kinds of real clients (administrative web interfaces, SSH, etc.).