通过SSH以Plesk域名系统用户身份连接AWS Lightsail遇权限问题求助

Hey Robin, I know how frustrating it is to spend a whole day stuck on an SSH permission issue—let’s break this down and get you access to that /var/www/vhosts/domain.tld directory. The core problem here is that the directory is owned by Plesk’s domain-specific system user, not the ubuntu user you’ve been trying to use. Here’s what to do:

1. Identify the Correct Plesk System User #

First, you need to use the system user that Plesk created for your domain, not ubuntu. To find this user:

• Log into your Plesk panel
• Navigate to your domain’s Hosting Settings
• Look for the System User field—this is the user that owns /var/www/vhosts/domain.tld (it might look something like domain_tld or a custom username you set)

2. Set Up SSH Keys for the Plesk System User #

Your existing key pair was configured for the ubuntu user, so we need to add the public key to the Plesk user’s authorized keys:

Option A: If you can access the server as root #

• SSH into the server as root first, then switch to the Plesk system user:

  su - your_plesk_system_username
  

• Create the .ssh directory (if it doesn’t exist) and set proper permissions:

  mkdir -p ~/.ssh
  chmod 700 ~/.ssh
  

• Append your public key (from key.pub) to the authorized_keys file:

  echo "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQ..." >> ~/.ssh/authorized_keys
  

• Lock down the permissions on authorized_keys (critical for SSH to accept the key):

  chmod 600 ~/.ssh/authorized_keys
  

Option B: Use the Plesk Panel (no root access needed) #

• In Plesk, go to System Users (under your domain or Tools & Settings)
• Edit the domain’s system user
• Scroll to the SSH Keys section, paste your public key content, and save

3. Connect with the Correct User #

Now use the Plesk system user to initiate the SSH connection—replace the username with the one you found earlier:

ssh -i key.pem -T your_plesk_system_username@your_server_ip

Once connected, you’ll be in the user’s home directory, and you can easily navigate to /var/www/vhosts/domain.tld (you’ll have full access since this user owns it).

4. Troubleshoot If You Still Get Permission Denied #

If you’re still seeing the error, check these common issues:

• Check SSH logs: Look at /var/log/auth.log on the server—this will tell you exactly why the key was rejected (e.g., wrong permissions, invalid key format)
• Verify SSH config: Ensure /etc/ssh/sshd_config has PubkeyAuthentication yes enabled (and no user-specific restrictions blocking key login)
• Local key permissions: Double-check that your local key.pem still has chmod 600 set—SSH will reject keys with overly open permissions

内容的提问来源于stack exchange，提问作者Robin Alexander