As a Systems Administrator or DevOps engineer working with on-premises systems, you have probably encountered a situation in which serial console access was required to troubleshoot or recover your system.
With Oracle Cloud Infrastructure it's possible to remotely access your Windows Server system using Special Administration Console (SAC) redirection over SSH. This feature, unique to Oracle Cloud Infrastructure, works with both bare metal and VM compute instances and gives you the ability to launch a command prompt or PowerShell remotely and interact with the system console.
SAC is intended to perform out-of-band administrative tasks on a system that is unable to access the network or is not entirely functional. Currently, the SAC console is not enabled by default in newly launched instances, so it must be configured using remote desktop access with boot configuration data.
Here are the steps to enable console redirection:
Open the CMD console and execute the following commands:
bcdedit /ems ON bcdedit /emssettings EMSPORT:1 EMSBAUDRATE:115200
Restart the server to complete the process.
The Windows instance is now configured to accept a connection to the serial port. You will need to create an instance-console-connection attachment in OCI. This operation can be done using the web console or oci-cli.
Using the web console, navigate to the instance details, select Serial Console Connections from the right menu and click Create Serial Console Connection.
Select the SSH key that will be used for this connection by either uploading the public key file or pasting the key contents into the text field.
After the attachment is created, you can retrieve the connection string from the right side menu.
After the connection has been established you will be greeted by the very minimal prompt:
You can find detailed information on all available commands from the Microsoft website, in this post I will concentrate on accessing PowerShell, which can be used to perform most of the administrative tasks.
SAC>cmd The Command Prompt session was successfully launched. SAC> EVENT: A new channel has been created. Use "ch -?" for channel help. Channel: Cmd0001 SAC>ch -si 1 Name: Cmd0001 Description: Command Type: VT-UTF8 Channel GUID: 876afc17-c4ef-11e7-80be-020017013bac Application Type GUID: 63d02271-8aa4-11d5-bccf-00b0d014a2d0 Press for next channel. Press 0 to return to the SAC channel. Use any other key to view this channel.
Press Enter and you'll be asked for credentials.
Please enter login credentials. Username: opc Domain : Password: ****************
Now you can use the PowerShell command to launch PowerShell or use any Windows command line utility to manage your system!
To learn more about serial console access, check out the documentation.