Stop "npm install" from being killed: add a swap file

Why does npm get killed?

npm is a tool that downloads code packages for Node.js projects. It can use a lot of memory. When the server runs out of memory (RAM), Linux protects itself and kills the biggest program. You see Killed.

Swap is a spare area on the disk that Linux uses like extra memory. It is slower than real RAM, but it stops crashes.

Step 1: Check current swap

1. Log in to your server with SSH.
2. Run this command:

free -h

It shows memory and swap in easy units. If the Swap line says 0, you have none.

Step 2: Create a swap file

Check you have free disk space first with df -h. These steps do not delete data, but a full disk causes other problems.

1. Create a 2 GB file:

fallocate -l 2G /swapfile

This reserves 2 GB of disk space for swap.

2. Lock the file so only root can read it:

chmod 600 /swapfile

3. Format it as swap:

mkswap /swapfile

4. Turn it on:

swapon /swapfile

5. Run free -h again. The Swap line should now show 2.0G.

Step 3: Keep it after a reboot

1. Back up the file first:

cp /etc/fstab /etc/fstab.bak

2. Add the swap file to the list of disks:

echo '/swapfile none swap sw 0 0' >> /etc/fstab

This line tells Linux to turn swap on at every start.

Step 4: Run npm again

1. Go to your project folder.
2. Run npm install again.

Quick recap

• "Killed" means the server ran out of memory.
• Check swap with free -h.
• Create, lock, format and enable a swap file.
• Add it to /etc/fstab to keep it after reboot.