Cannot allocate memory error while computing files - Setup Swap space

ActionView::Template::Error (Cannot allocate memory - nodejs /tmp/execjs20131021-26716-fckzo3.js 2>&1
Nodejs is used to compile javascript at runtime. In RoR applications, this error comes when server is started in production mode which compiles the assets or while running rake assets:precompile.
check for swap space and allocate
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$ sudo swapon -s
Filename Type Size Used Priority

It confirms swap space doesnot exists.

Check for the memory space.

$ df -h

Filesystem      Size  Used Avail Use% Mounted on

udev            287M  8.0K  287M   1% /dev

tmpfs           118M  184K  118M   1% /run

none            5.0M     0  5.0M   0% /run/lock

none            295M     0  295M   0% /run/shm

none            100M     0  100M   0% /run/user

/dev/xvda1      7.9G  4.2G  3.4G  56% /

We can use the /dev/xvda1  and allocate 512mb for swap.

Create swap file using dd command.

$ sudo dd if=/dev/zero of=/swapfile bs=1024 count=512k

524288+0 records in

524288+0 records out

536870912 bytes (537 MB) copied, 34.9025 s, 15.4 MB/s

File name can be changed by changing the name to any from swapfile.

sudo mkswap /swapfile

Setting up swapspace version 1, size = 524284 KiB

no label, UUID=3e47fe14-e167-452d-a7b2-e72e8e1a6gd2

sudo swapon /swapfile

swapon -s

Filename Type Size Used Priority

/swapfile                               file 524284 0 -1

use the editor of your choice and edit the fstab entry to avoid losing swap space on reboot.

sudo vi /etc/fstab

paste the below line:

/swapfile       none    swap    sw      0       0 

https://www.digitalocean.com/community/articles/how-to-add-swap-on-ubuntu-12-04

sudo chown root:root /swapfile 
sudo chmod 0600 /swapfile