Error encountered

After editing partitions to enlarge my vagrant box. The following error is encountered and the machine took 1min30 to boot:

A start job is running for dev-disk-by\x2duuid

Solution

List machine partition by-uuid

vagrant@moodle-prod:~$ ls -l /dev/disk/by-uuid/
total 0
lrwxrwxrwx 1 root root 10 Nov 13 08:49 a01bd0bf-1ffc-400d-b383-d74354750926 -> ../../sda2
lrwxrwxrwx 1 root root 10 Nov 13 08:49 db36bd9a-c8f7-4b02-bb1a-81e4913a21d7 -> ../../sda1

Check /etc/fstab file

vagrant@moodle-prod:~$ sudo cat /etc/fstab
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
# / was on /dev/vda1 during installation
UUID=db36bd9a-c8f7-4b02-bb1a-81e4913a21d7 /               ext4    errors=remount-ro 0       1
# swap was on /dev/vda5 during installation
UUID=8d7d9300-7fd3-4a5a-bfd1-9bc61a20fabd none            swap    sw              0       0
/dev/sr0        /media/cdrom0   udf,iso9660 user,noauto     0       0

SWAP UUID has changed

Problem: SWAP UID has changed

# swap was on /dev/vda5 during installation
UUID=8d7d9300-7fd3-4a5a-bfd1-9bc61a20fabd none            swap    sw     

Edit this line with the new UUID (change '8d7d9300-7fd3-4a5a-bfd1-9bc61a20fabd' to 'a01bd0bf-1ffc-400d-b383-d74354750926') in /etc/fstab:

UUID=a01bd0bf-1ffc-400d-b383-d74354750926 none            swap    sw              0       0

Check

Everything is now fine! Error solved!

source

If you need to activate debug but you cannot access moodle admin page, this article is for you:

Step 1: note original settings

SELECT name, value
FROM mdl_config
where name ='debug' or name ='debugdisplay'
;

for instance :

debug   0
debugdisplay    0

Step 2 : setup debug config in db

UPDATE mdl_config SET VALUE = 32767 WHERE name = 'debug';
UPDATE mdl_config SET VALUE = 1 WHERE name = 'debugdisplay';

Step 3: clear cache from CLI

php  moodle/admin/cli/purge_caches.php

Step 4: restore original settings

UPDATE mdl_config SET VALUE = 0 WHERE name = 'debug';
UPDATE mdl_config SET VALUE = 0 WHERE name = 'debugdisplay';

Access your server using ssh key authentication.

If you loose your time, typing password, this is for you:

Generate ssh authentication keys on the client side

ssh-keygen -t rsa

Create a .ssh folder on the server

ssh pi@192.168.1.84 mkdir -p .ssh

Grant the client to access to the server using public key

cat .ssh/id_local.pub | ssh pi@192.168.1.84 'cat >> .ssh/authorized_keys'

Connect to server without password

ssh pi@192.168.1.84

That's it, you can now access your server whithout typing your password!