The cloud servers used in this course do not have enough memory (RAM) to run/compile many things at once. But you can easily add swap space to solve this issue.
Swap space in Linux is used when there is no more available physical memory (RAM). If the system needs more memory resources and the RAM is full, inactive pages in memory are moved to the swap space (on disk).
Adding 2 gigabytes of swap space should be enough for our purposes.
Run the following commands to make sure you disable any previous swap file you might have created during the exercises:
# (It's okay if this command produces an error.)
$> sudo swapoff /swapfile
$> sudo rm -f /swapfileUse the following commands to create and mount a 2-gigabyte swap file:
$> sudo fallocate -l 2G /swapfile
$> sudo chmod 600 /swapfile
$> sudo mkswap /swapfile
Setting up swapspace version 1, size = 2 GiB (2147479552 bytes)
no label, UUID=3c263053-41cc-4757-0000-13de0644cf97
$> sudo swapon /swapfileYou can verify that the swap space is correctly mounted by displaying available
memory with the free -h command. You should see the Swap line indicating the
amount of swap space you have added:
$> free -h
total used free shared buff/cache available
Mem: 914Mi 404Mi 316Mi 31Mi 193Mi 331Mi
Swap: 2.0Gi 200Mi 1.8GiThis swap space is temporary by default and will only last until your reboot your server. To make it permanent, you must tell your server to mount it on boot.
You can see the currently configured mounts with this command (the output may not be exactly the same):
$> cat /etc/fstab
# CLOUD_IMG: This file was created/modified by the Cloud Image build process
UUID=b1983cef-43a3-46ac-0000-b5e06a61c9fd / ext4 defaults,discard 0 1
UUID=0BC7-0000 /boot/efi vfat umask=0077 0 1
/dev/disk/cloud/azure_resource-part1 /mnt auto defaults,nofail,x-systemd.requires=cloud-init.service,comment=cloudconfig 0 2/etc/fstab file can
prevent your server from rebooting.)
To make the swap space permanent, execute the following command to add the
appropriate line to your server's /etc/fstab file:
$> echo "/swapfile none swap sw 0 0" | sudo tee -a /etc/fstabThis line tells your server to mount the swap file you have created as swap
space on boot. You should see the new line at the end of the /etc/fstab file
if you display its contents again:
$> cat /etc/fstab
# CLOUD_IMG: This file was created/modified by the Cloud Image build process
UUID=b1983cef-43a3-46ac-0000-b5e06a61c9fd / ext4 defaults,discard 0 1
UUID=0BC7-08EF /boot/efi vfat umask=0077 0 1
/dev/disk/cloud/azure_resource-part1 /mnt auto defaults,nofail,x-systemd.requires=cloud-init.service,comment=cloudconfig 0 2
/swapfile none swap sw 0 0You can run the following command to check that you did not make any mistakes. It's okay if you have a couple of warnings about the swap file. These are expected since you've just added it and have not rebooted yet.
$> sudo findmnt --verify --verbose
/
[ ] target exists
[ ] FS options: discard,commit=30,errors=remount-ro
[ ] UUID=bf171e20-4158-4861-0000-1443ece8c413 translated to /dev/sda1
[ ] source /dev/sda1 exists
[ ] FS type is ext4
...
none
[W] non-bind mount source /swapfile is a directory or regular file
[ ] FS type is swap
[W] your fstab has been modified, but systemd still uses the old version;
use 'systemctl daemon-reload' to reload
0 parse errors, 0 errors, 2 warningsIF everything looks ok, reboot your server:
$> sudo rebootReconnect to your server over SSH and run the free -h command again. The swap
space should still be enabled after reboot:
$> free -h
total used free shared buff/cache available
Mem: 914Mi 404Mi 316Mi 31Mi 193Mi 331Mi
Swap: 2.0Gi 200Mi 1.8GiYou can also see the currently available swap space and how much is used with the
htopcommand which shows it as theSwpbar at the top (you can quit it withqonce it is open).For more information, see the fstab Linux man page and How to Add Swap Space on Ubuntu 20.04.