Uly.me

cloud engineer

Linux Screen

If you don’t have it installed.

yum install screen
apt install screen

Before you run a process, run screen, and detach.

screen
# run the command
ping yahoo.com
# ctrl-a and ctrl-d to detach

To reattach, get a list of screen sessions, and attach to it.

screen -ls
# result is somewhat similar to below
4452.hostname
# attach to it
screen -dr 4452.hostname

To stop, just type exit from the screen terminal.

Chroot A Boot Disk

Here’s a quick way to chroot another boot disk. Attach the rescued boot disk first. Run lsblk and mount. 

lsblk
mount -t xfs -o nouuid /dev/xvdf2 /mnt
mount --bind /proc /mnt/proc
mount --bind /sys /mnt/sys
mount --bind /dev /mnt/dev
chroot /mnt
cd /mnt
exit

Unmount when done.

umount /mnt/proc
umount /mnt/dev
umount /mnt/sys
umount /mnt

AWS CLI Lightsail

Get instance details

aws lightsail get-instance --instance-name your-server

Get instance state

aws lightsail get-instance-state --instance-name your-server

Create a snapshot

aws lightsail create-instance-snapshot \
--instance-snapshot-name your-server-new-snapshot-201905192200 \
--instance-name your-server

Create disk from snapshot

aws lightsail create-disk-from-snapshot \
--disk-name your-server-new-boot-disk \
--disk-name your-server-new-snapshot-201905192200 \
--availability-zone us-east-1a
--size-in-gb 50

Attach Disk

aws lightsail attach-disk \
--disk-name your-server-new-boot-disk \
--instance-name your-server \
--disk-path /dev/sda1

Create instance from snapshot

aws lightsail create-instance-snapshot \
--instance-snaphot-name your-server-new-snapshot-201905192200
--instance-name your-server

Attach Static IP Address

aws lightsail attach-static-ip \
--static-ip-name your-ip-name \
--instance-name your-server