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Nextcloud Maintenance

04 Aug 2020
setup
 
nextcloud
 
snap
 

Setting up Nextcloud Server is half of the work - the other half, maintenance, is as important, if not more.

Basics

The occ Command

occ (OwnCloud Console), originated from Owncloud, is the command-line interface for server management operations, e.g. upgrading, backing up, configuring the server. Depending on the installation method, occ is run as:

  • Non-snap installation: sudo -u www-data php /var/www/[own|next]cloud/occ [--args]. Original installations typically ships occ as a wrapper php scripts, where the core functionality are called from other php source scripts. It is required to execute the occ script with php and run as user www-data;
  • snap installation: sudo nextcloud.occ [--args]. occ is shipped as a executable binary.

Notice that sudo might be required depending on user permissions. For the remaining of the post, we will simply use occ to denote the command.

Other Dependencies

Other than occ, snap also comes in handy with some dependencies and tools pre-installed. For example,

  • Non-snap installations require setting up apache server, whilst snap bundles the dependencies into the Nextcloud itself;
  • snap installation comes with nextcloud.mysql-client, nextcloud.mysqldump as a bundled database solution;
  • snap installation also comes with nextcloud.enable-https, in place of external tools (e.g. certbot), and many more.

For the rest of this post, we use a snap installation as an example.

Directories

For a snap installation, it is helpful to know how are the directories of snap applications organized. There are mainly two directories that we are concerned with in this post:

Dir /snap[/nextcloud]

Generally speaking, /snap contains the core files of the applications. For example, /snap/bin contains the applications aliases:

$ cd /snap/bin; ls *nextcloud*
nextcloud.disable-https   nextcloud.enable-https  nextcloud.export     nextcloud.import
nextcloud.manual-install  nextcloud.mysql-client  nextcloud.mysqldump  nextcloud.occ

And /snap/core contains the virtual file system used by snap applications:

$ cd /snap/core/current/; ls
bin   boot  dev  etc   home  lib  lib64  media  meta  mnt  opt
proc  root  run  sbin  snap  srv  sys    tmp    usr   var  writable

/snap/nextcloud contains the core files required to run the Nextcloud application:

$ cd /snap/nextcloud/current; ls
bin  cgi-bin  config    error  fixes  icons  lib  logs  meta  my.cnf  README  share
support-files utilities certbot_nextcloud_plugin  conf  docs  etc     htdocs  include
LICENSE  man  modules  php  setup.py  snap   usr   var

where bin holds the binaries aliased in /snap/bin, lib; htdocs, include , usr, etc holds many scripts and libraries; so on and forth.

For application level configuration and maintenance, it is usually not required to mess with /snap.

Dir /var/snap[/nextcloud]

On the other hand, /var/snap is more like a container for application data. Peeking in

$ cd /var/snap/nextcloud; ls
23027  23171  common  current  lost+found

there are two main targets common and current (23027 and 23171 are two versions of the applications and current is a symlink to the latter one).

common contains users’ data:

$ cd /var/snap/nextcloud/common/nextcloud/data; ls
admin  appdata_oc5ijq344eib  user1  user2  files_external  index.html  nextcloud.log

and current contains app data (including that of the apps installed as dependencies)

$ cd /var/snap/nextcloud/current; ls
apache  certs  mysql  nextcloud  php  redis

which includes logs, configs, etc.

Admin

Nextcloud web interface provides access to the admin user to many administrative functionalities (add users, config changes, etc). Most day-to-day tasks can be easily accomplished using that alone. If circumstances arise such that other measurements are to be taken, we might need to get our hands dirty.

First thing first, always turn on maintenance mode before making anything changes (and back off when done):

$ occ maintenance:mode --[on|off]

Restart

Restarting the application using snap:

$ sudo snap disable nextcloud
$ sudo snap enable nextcloud

Upgrade

Upgrade with snap installation is fairly simple:

# first update the snap package
$ sudo snap refresh nextcloud
# now upgrade in occ
$ occ upgrade

Logs

To read the logs, simply

$ snap logs nextcloud[.app]

Database Management

Snap uses its own bundled version of database nextcloud.mysql-client. Log in

# For reference: 'mysql -u root -p'
$ sudo nextcloud.mysql-client

Manual Changes and Syncing

Sometimes manually forcing syncing the changes are required (e.g. manually resolving failed syncs or corruptions, after making large changes that are much faster to add them manually to data directory /var/snap/nextcloud/common/nextcloud/data, etc). A simple command for this purpose:

$ occ files:scan --all

Backup and Restore

Nextcloud might be often used as a file backup service, but strictly speaking it is more of a file syncing service. It is important for the admin to set up proper backup solution to avoid losing data over accidental changes or server error (including faulty hardware, etc).

Backup Artifacts

When backing up, there are three main artifacts:

  • server config: /var/snap/nextcloud/current/nextcloud/config/config.php;
  • database: includes user information, permissions, file ownership and sharing information, etc. Nextcloud supports many different database software, e.g. mysql, mariadb, etc;
  • data directory: /var/snap/nextcloud/common/nextcloud;

Scripts, Tools and Automation

Server config:

# save config
$ sudo rsync /var/snap/nextcloud/current/nextcloud/config/config.php /backup/nextcloud/config/config_`date +"%Y-%m-%d"`.php
# restore config
$ sudo rsync /backup/nextcloud/config/config_YYYY-MM-DD.php /var/snap/nextcloud/current/nextcloud/config/config.php

Database:

# dump database
$ sudo nextcloud.mysqldump --single-transaction > /backup/nextcloud/database/nextcloud-sql_`date +"%Y-%m-%d"`.bak
# restore database, first recreate the 'nextcloud' database, then load it from backup file
$ sudo nextcloud.mysql-client -e "DROP DATABASE nextcloud";
$ sudo nextcloud.mysql-client -e "CREATE DATABSE nextcloud";
$ sudo nextcloud.mysql-client nextcloud < /backup/nextcloud/database/nextcloud-sql_YYYY-MM-DD.bak

Because the user data is relatively large, we use Borg Backup as the back up solution. It is feature-rich, reliable, compression-friendly and supports incremental backup nicely.

# Initialize a repo for nextcloud user data
$ borg init --encryption none /backup/nextcloud/data-borg/
# Create a backup. Borg automatically compresses and deduplicates. Notice the 'sudo' is required because 'common' is 'root'-owned.
$ sudo borg create --progress /backup/nextcloud/data-borg::userdata-$(date '+%Y-%m-%d') /var/snap/nextcloud/common/nextcloud
# Borg requires providing full-path for extraction. Head to root dir '/' before executing.
# The starting '/' at the extraction path is intentionally omitted.
$ sudo borg extract --progress /backup/nextcloud/data-borg::userdata-YYYY-MM-DD var/snap/nextcloud/common/nextcloud
# If unsure about the name, query the repo or archive
$ sudo borg [list|info] /backup/nextcloud/data-borg[::userdata-YYYY-MM-DD]

Alternately, if one wishes to use rsync instead, it is important to toggle the right flags to preserve all information:

# -A: preserve Access Control Lists; 
# -a: archive. Recursive, preserve everything (with a few exceptions);
# -x: one-file-system.
# Backup
$ sudo rsync -Aaxv /var/snap/nextcloud/common/nextcloud /backup/nextcloud/data-rsync/nextcloud-backup_$(date '+%Y-%m-%d')
# Restore
$ sudo rsync -Aaxv /backup/nextcloud/data-rsync/nextcloud-backup_YYYY_MM_DD /var/snap/nextcloud/common/nextcloud

cron

Domain

Depending on how the domain was set up, routinely maintenance might be required.

  • Free domain name providers might require routinely verification (e.g. NOIP require monthly logins);
  • Dynamic DNS needs to be set up if the server’s public IP is not fixed;
  • SSL certification needs to be renewed every couple of years (exact length depends on CA). Snap installation of Nextcloud integrated certbot as a dependency, so renewal is straight-forward: 
    [sudo] nextcloud.enable-https lets-encrypt

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