Trying to upgrade Ghost and install the ghost-cli I was getting the below error on my $5 Digital Ocean droplet...

/var/www/ghost$ sudo npm i -g ghost-cli
npm WARN deprecated [email protected]: Use uuid module instead
Killed        .....] | extract:ghost-cli: sill doParallel extract 569

Digital Ocean recommend their $10 droplet for Ghost, however I've only got this small blog running, and the $5 one seems to run it fine for me (especially when combined with Cloudflare). The fix to this was easy, I just had to add some swap space, which Digital Ocean has this guide for.

Once I'd added the swap, it installed without any further problems...