Hey there! Great question—you absolutely don’t need to rely on manual logins or cobble together your own scripts to restart all Ambari Agents in your cluster. Ambari Server has native, built-in ways to do this in one go, which are way more reliable and easier to manage than rolling your own solution. Let me walk you through both the graphical and command-line options:

This is the most straightforward way if you prefer a graphical interface:

• Log into your Ambari Server web dashboard (typically at http://<your-ambari-server-ip>:8080) using your admin credentials.
• Click the Hosts tab at the top of the page to view all cluster hosts.
• Use the top checkbox to select all 8 client hosts (or pick specific ones if needed).
• Look for the Actions dropdown in the top-right corner of the hosts list.
• Hover over Restart and select Restart Agents from the submenu.
• Confirm the action when prompted—Ambari will handle remotely triggering the Agent restart on every selected host, and you can monitor the progress right in the UI.

If you want to script this or prefer working from the command line, the Ambari Admin CLI has you covered:

1. On your Ambari Server host, launch the CLI shell:

   ambari-shell
   

2. Authenticate with your admin account:

   login --user=admin --password=<your-admin-password>
   

3. To restart Agents on all hosts in the cluster:

   restart agents --all
   

4. If you ever need to target only specific hosts (though you mentioned all 8), you can list them explicitly:

   restart agents --hosts=client-host-1,client-host-2,client-host-3,client-host-4,client-host-5,client-host-6,client-host-7,client-host-8
   

5. When you’re done, exit the CLI with:

   exit
   

A Quick Note on Why This Is Better Than Custom Scripts #

• Built-in reliability: Ambari handles SSH connections, error checking, and retries automatically—you don’t have to debug failed SSH commands or missing dependencies.
• Centralized tracking: All restart actions are logged in Ambari, so you can easily verify which hosts succeeded or failed, and troubleshoot any issues right from the dashboard.
• OS consistency: Ambari uses the correct service management tool (systemd, init.d, etc.) for each host’s operating system, avoiding mistakes from manual command execution.

内容的提问来源于stack exchange，提问作者NapdaN