Set Up a 2GB Swap on a Remote VPS with a Simple Script
Running a small VPS with limited memory can be frustrating, especially when processes get killed due to low memory. A quick and easy way to help prevent this is by setting up a swap file.
This script will
- Checks if swap already exists on the remote machine.
- If not, it creates a 2GB swap file and enables it.
- Adds the swap file to
/etc/fstabto make it permanent.
The script uses scp to copy a temporary script to the remote machine and ssh to execute it. Here’s the full script:
#!/bin/bash
# Check if machine name is provided
if [ -z "$1" ]; then
echo "Usage: $0 <machine-name>"
exit 1
fi
REMOTE_MACHINE=$1
SWAPFILE=/swapfile
SIZE=2048
# Generate remote script content
REMOTE_SCRIPT=$(cat <<EOF
#!/bin/bash
if swapon --show | grep -q "$SWAPFILE"; then
echo "Swap is already enabled on $SWAPFILE"
exit 0
fi
sudo dd if=/dev/zero of=$SWAPFILE bs=1M count=$SIZE
sudo chmod 600 $SWAPFILE
sudo mkswap $SWAPFILE
sudo swapon $SWAPFILE
if ! grep -q "$SWAPFILE" /etc/fstab; then
echo "$SWAPFILE none swap sw 0 0" | sudo tee -a /etc/fstab
fi
free -h
EOF
)
# Save remote script locally
echo "$REMOTE_SCRIPT" > /tmp/create_swap.sh
# Copy script to remote machine and execute it
scp /tmp/create_swap.sh $REMOTE_MACHINE:/tmp/
ssh $REMOTE_MACHINE "bash /tmp/create_swap.sh"
# Cleanup
ssh $REMOTE_MACHINE "rm /tmp/create_swap.sh"
How It Works
- The script checks if the swap file already exists by running
swapon --showon the remote machine. - If swap is already enabled, it exits.
- Otherwise, it creates a 2GB swap file (
/swapfile), sets the right permissions, and adds it to/etc/fstabso it’s automatically enabled after a reboot.
Usage
-
Save the script as
create_swap.shand make it executable:chmod +x create_swap.sh -
Run the script with the remote machine name:
./create_swap.sh <remote-machine>
And that's it! The script takes care of everything for you, ensuring your VPS has a swap file ready to handle memory spikes.