The image is docker image you are using, in this example I’m using docker image built by dpolyakov (https://hub.docker.com/r/dpolyakov/docker-node-latest-with-rsync/) If you want specific build image just created your self.
The pipelines is contain step by step to build and deploy your source code, Cache meaning we cache node and node_modules so we reduce the time for installing node modules.
In script we put step by step to install your source code, this step is different each framework, you can also do integration testing or tdd test in this script.
Rsync is tools to copy the result of build to remote server. (https://en.wikipedia.org/wiki/Rsync)
The ssh command is to stop/start/restart the service inside remote server.