title: Adding ssh-keys to gcp metadata
body: <p>I am new to Google Cloud and am facing a challenge while adding ssh-keys to google metadata (project-wide) with gcloud command line. </p>
  
  <p>When I try to add ssh-key into Google metadata (with command :: <code>gcloud compute project-info add-metadata --metadata-from-file ssh-keys=[LIST_PATH]</code>) along with the new ssh-key which I am trying to add, I also have to specify all existing ssh-keys in the source file. (the source file is the file where we store ssh-key value). because I will add all the ssh-keys which are present in source file so if I do not keep existing ssh-keys in source file and keep only one key, it will add only this single key into metadata and rest of the existing keys will be removed.</p>
  
  <p>So what I am trying to achieve is to add any single ssh-key to the metadata without affecting existing keys. Because this will be a repeated process for many of the machines in my environment, and I cannot track existing keys every time.</p>