Create a Console Connection to DBCS system in OCI if you Forgot or Lost Keys

Create a Console Connection to DBCS system in OCI

I was working for an OCI customer and they came to me for an issue for PROD DBCS system. I check and found someone tempered the file permission and no command was working after logging to DB node.

As DBCS is a PAAS service so we cannot go to the OS boot directly.

To fix there problem I created a Console Connection to login on DBCS underlying OS and correct the permissions.

A serial console connection to bare metal or virtual machine DB system allows you to manage and troubleshoot your system in single-user mode using an SSH connection

Steps:

1) Go to DB System on OCI an Click the respective DB System name

2) On the Left Bottom go to Resources and select Console Conection.

3) Click on Create Console Connection

4) Paste the SSH key of the server from where I would be connecting. I am using another server to connect to it.

5) Now once the Console Connection is Ready. Copy the ssh string and connect from Server.

You should see a login prompt, We don't need to login.

6) Now Go Back to OCI console for DB system and Go To Resource >Nodes and Reboot.

7) As soon as we click reboot, go back to the Server from where console connection was created , we will see its going and and starting back. Keep pressing arrow key until we get grub menu.

8) press 'e' and 

At the end of that line, add the following and press Cntrl +X

init=/bin/bash

9)  Now we can see from serial connection directly connected to the server.

10) If we want to modify any thing the run below before modifying.

a) Run Command "/usr/sbin/load_policy -i” - to preserve the SELinux policies for the files you will modify.

b) Run Command "/bin/mount -o remount,rw /“ - to remount the root partition with read/write permissions.

For doing same on VM Click Here

11) Delete the Create console connection once the work is done.

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