Google Cloud Platform SSH下载无权限求助：VM实例根目录文件下载失败

Hey there, let's work through those two permission problems you're hitting with your GCP VM over SSH—they're super common, and we can sort them out quickly!

1. Can't Download Files via SSH #

First, let's troubleshoot the general file download failure. Here are the most likely fixes:

• Check file/directory permissions on the VM
  Run this command on the VM to see if your user has read access to the file you want to download:

  ls -l /path/to/your/target-file
  

  Look for the r (read) permission in the user/group section. If you don't have it, you'll need to either:

  • Copy the file to a directory you own (like your home folder) first:

    sudo cp /path/to/target-file ~/
    sudo chown $USER:$USER ~/target-file
    

    Then download from your home folder instead.
  • Use sudo to perform the download directly (if using scp or gcloud compute scp—more on that below).

• Verify your download command syntax
  If you're using gcloud compute scp, make sure you're including the --sudo flag if the file requires elevated permissions:

  gcloud compute scp --sudo your-vm-name:/path/to/target-file ./local-directory/
  

  For standard scp, you can run it with sudo on the VM side like this:

  scp your-ssh-user@vm-external-ip:"sudo cat /path/to/target-file" ./local-file-name
  

2. Can't Access/Download Files in the /root Directory #

The /root directory is restricted to the root user by default—regular SSH users can't read or write there without elevated privileges. Here's how to handle this safely:

• Option 1: Switch to root user temporarily
  Use this command to log into a root shell (your user needs sudo access, which GCP's default VM users have):

  sudo -i
  

  Now you can navigate to /root, view files, or initiate a download directly. When you're done, type exit to go back to your regular user.

• Option 2: Copy the file to your home folder first
  Instead of working directly in /root, copy the file to a directory you control, then adjust permissions:

  sudo cp /root/your-root-file ~/
  sudo chown $USER:$USER ~/your-root-file
  

  Now you can download the file from your home folder without permission issues.

• Option 3: Download directly with sudo (no root shell)
  If you're using gcloud compute scp, the --sudo flag lets you bypass root directory restrictions:

  gcloud compute scp --sudo your-vm-name:/root/your-root-file ./local-folder/
  

  For standard scp, use this trick to read the file as root and pipe it to your local machine:

  scp your-ssh-user@vm-external-ip:"sudo cat /root/your-root-file" ./local-root-file
  

Important Notes #

• Never modify permissions on /root itself—this can break system security and functionality. Always copy files out instead.
• If you're using the GCP Console's browser-based SSH window, you'll need to copy the file to your home folder first before using the "Download file" feature, since the browser session runs as your regular user.

Hope these steps resolve your permission issues! If you run into any weird edge cases, feel free to share more details.

内容的提问来源于stack exchange，提问作者John Appleseed