Option to automatically create swap space when creating droplet?

April 29, 2015 3k views
Control Panels Configuration Management Ubuntu
nicbarker
By:
nicbarker

Hi guys,
Huge fan of DO - been using it for a few years now on heaps of different projects. One thing I've noticed myself doing repeatedly on almost every small (i.e 20gb) droplet that I spin up is creating a gig or so of swap space.

Seeing as this is such a common thing to do for a lot of use cases (i.e running passenger or unicorn on a 512mb ram droplet) would you consider adding an option to the "create droplet" wizard that allows you to automatically create / turn on swap of a certain size?

Cheers,
Nic

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2 Answers
ryanpq MOD April 29, 2015

We do have this feature on some one-click applications (where a swap file is automatically created on smaller droplets) and some distributions like FreeBSD include a swap partition by default. You can add a swap file at creation by using the following script in user-data on the create page:

#!/bin/bash
 sudo fallocate -l 1G /swapfile;
 chmod 600 /swapfile;
 mkswap /swapfile;
 swapon /swapfile;
echo "/swapfile   none    swap    sw    0   0" >> /etc/fstab;

This will create a 1GB swap file as soon as your droplet boots for the first time and add it to your fstab to be automatically used on each subsequent boot.

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shumoapp October 12, 2017

If you are creating a droplet using the digitalocean docker-machine driver, put this unit in your cloud-config file (the one you provide to the --digitalocean-userdata parameter)

  units:
    - name: runcmd.service
      command: start
      content: |
        [Unit]
        Description=Enable swap

        [Service]
        Type=oneshot
        ExecStart=/bin/sh -c "\
          sudo fallocate -l 4G /swapfile && \
          sudo chmod 600 /swapfile && \
          sudo mkswap /swapfile && \
          sudo swapon /swapfile && \
          sudo echo "/swapfile   none    swap    sw    0   0" | sudo tee --append /etc/fstab"
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