You will need to do the following prior to changing the kernel:
-Detach the root volume of the instance which is failing instance health checks after the update was performed
-Attach the instance to a recovery instance
-Prepare the volume using the following commands:
The following command verifies that the root volume has successfully been attached to your recovery instance:
[ec2-user@bastian ~]$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda 202:0 0 100G 0 disk
└─xvda1 202:1 0 100G 0 part /
xvdf 202:80 0 8G 0 disk
└─xvdf1 202:81 0 8G 0 part
The following command creates a temp mount point called /mount (You can name this to whatever you want though):
[ec2-user@bastian ~]$ sudo mkdir /mount
We use the mount command to mount the volume:
[ec2-user@bastian ~]$ sudo mount /dev/xvdf1 /mount
We then use df to confirm the volume has been mounted:
[ec2-user@bastian ~]$ df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 231M 68K 231M 1% /dev
/dev/xvda1 99G 5.3G 93G 6% /
/dev/xvdf1 8.0G 3.4G 4.7G 43% /mount
Next, we will need to mount the following from our recovery instance to our mount point( /dev, /dev/shm, /proc, /sys ):
[ec2-user@bastian ~]$ sudo mount -o bind /dev /mount/dev
[ec2-user@bastian ~]$ sudo mount -o bind /dev/shm /mount/dev/shm
[ec2-user@bastian ~]$ sudo mount -o bind /proc /mount/proc
[ec2-user@bastian ~]$ sudo mount -o bind /sys /mount/sys
Next, we isolate the volume using chroot:
[ec2-user@bastian ~]$ sudo chroot /mount
After doing the above, you volume is now ready to run the following based on the flavor you are using:
REDHAT 6 AND AMAZON LINUX 1:::
[ec2-user@bastian ~]$ sudo awk ‘/\s*kernel/{print}’ /boot/grub/menu.lst
[ec2-user@bastian ~]$ sudo sed -i ‘/^default/ s/0/1/’ /boot/grub/grub.conf
[ec2-user@bastian ~]$ exit
FOR UBUNTU::::
[ubuntu@bastian ~]$ sudo awk -F\’ /\s*menuentry/{print\$2}’ /boot/grub/grub.cfg
[ubuntu@bastian ~]$ sudo grub-set-default 1
[ubuntu@bastian ~]$ cat /boot/grub/grubenv | grep saved
saved_entry=1
[ubuntu@bastian ~]$ sudo grub mkconfig -o /boot/grub/grub.cfg
[ubuntu@bastian ~]$ exit
REDHAT AND AMAZON LINUX 2::::
@bastian ~]$ sudo awk -F\’ /\s*menuentry/{print\$2}’ /boot/grub/grub.cfg
@bastian ~]$ sudo grub2-set-default 1
@bastian ~]$ sudo cat /boot/grub2/grubenv | grep saved
saved_entry=1
@bastian ~]$ sudo grub2 mkconfig -o /boot/grub/grub.cfg
@bastian ~]$ exit
No token or token has expired.