Comet Backup installation 

Windows 

System Requirements 

  • x86_32+SSE2 or x86_64 CPU architecture
  • Minimum 1024x600 screen resolution
  • Windows Vista, 7, 8, 8.1, 10, or newer
  • Windows Server 2008, 2008 R2, 2012, 2012 R2, 2016, or newer

As of Comet 19.12.5, TLS 1.2 is mandatory in Comet Server. Windows Server 2008 users may require KB4019276 to continue accessing Comet Server; this update is also required for ESU (Extended Security Updates) for Windows Server 2008.

Microsoft ended Extended support for Windows 7, Server 2008, and Server 2008 R2 on January 14th 2020. Future versions of Comet may drop support for older versions of Windows no longer under active security support from Microsoft.

Not compatible with Windows XP (released 2001) 

At the time of writing, there is no version of Comet available for Windows XP / Server 2003. All versions of Comet rely heavily on features that were only introduced in Windows Vista / Server 2008.

Windows XP / Server 2003 no longer receives security patches from Microsoft. It is unsafe to connect such a machine to the internet. If you are attempting to supply backup services to a customer in this situation, you should arrange to first upgrade their operating system with urgency.

Despite the above warning, our company would like to support as many platforms as possible. It might become supported in the future.

Workarounds 

You can work around this issue by

  • installing Comet Backup on another machine, and then backup the XP machine over the network; or
  • virtualizing the XP machine, and backing up the VM guest from the VM host. This also allows you to remove internet access from the XP machine.

Install 

Run the CometBackup_install.exe file and follow the prompts.

Once installed, the client software prompts for account details to log in.

Silent install (advanced) 

Comet allows you to install and configure the software silently, by running install.exe /CONFIGURE=user:password via your remote management software.

Service account 

Comet automatically creates a Virtual Account (NT SERVICE\backup.delegate) with all necessary permissions to back up files on the PC.

Isolating Comet Backup under a Virtual Account is supported on Windows 7 or later, and Windows Server 2008 R2 or later when that server is not a Domain Controller. On other machines (e.g. Windows Server 2008 RTM, and domain controllers) the backup service will run as LOCAL SYSTEM by default.

On a Domain Controller running Windows Server 2008 R2 or later, we recommend configuring a Managed Service Account inside Active Directory for the backup service. This allows you to isolate the backup service permissions in a password-less service account. You should apply this to the backup.delegate service (but not the backup.elevator service, used for software updates).

Upgrading 

The installer will safely remove and upgrade any prior version of Comet Backup, including those with a different software branding.

If the product name is changed as a result of the installation process, the newly-branded software may be installed into the old-branded directory name. You can avoid this issue by completely uninstalling and reinstalling the software.

Silent upgrade (advanced) 

You can silently upgrade the software remotely via the Comet Server interface, or by running install.exe /S via your remote management software.

Service account 

In Comet 19.12.1 and later, if you customize the backup.delegate service to use any other user account, your changes will be preserved in any future software upgrade.

In Comet 19.3.0 and later prior to 19.12.1, such changes will be preserved as long as the target user account is not LOCAL SYSTEM or NT SERVICE\backup.delegate.

Prior to Comet 19.3.0, different restrictions were in place for this process. For more information, please see the documentation that is included with your previous version of Comet Server.

Uninstall 

The software can be uninstalled via the "Apps and Features" section in the Windows Control Panel.

During this process, you may be prompted whether you wish to preserve any username/password credentials saved on this computer.

You can also remove the saved credentials manually by deleting the AppData\Roaming\backup-tool\config.dat file. If the backup.delegate service was running as the NT SERVICE\backup.delegate user, this is stored in the C:\Users\backup.delegate\AppData\Roaming\backup-tool\ directory; the path may differ if the service was running as another user account.

Silent uninstall 

You can silently uninstall Comet Backup for Windows by passing the /S command-line argument (e.g. "C:\Program Files\Comet Backup\Uninstall.exe" /S).

If you also want to remove the saved username/password credentials, add this command-line "C:\Program Files\Comet Backup\Uninstall.exe" /S /ISDELETECREDENTIAL=yes

macOS 

System Requirements 

  • x86_64 CPU architecture
    • Including x86_64h
  • OS X 10.10 or later
    • We recommend using a version of macOS that receives ongoing security support from Apple (usually the last 3 versions)
    • OS X 10.9 was supported by Comet 19.12.1, the Comet 19.11.x series, and older versions of Comet

Install 

The macOS operating system requires codesigning to be enabled in order to launch a downloaded .pkg file. If you have not configured codesigning for macOS, you will be unable to launch the installer. However, you can bypass this by right-clicking the .pkg file and choosing Open.

Run the Comet Backup.pkg file and follow the prompts.

Once installed, the client software prompts for account details to log in.

If you are running the .pkg file from the Downloads directory, macOS will offer to move the .pkg file to the Trash after a successful installation.

Upgrading 

The installer will safely remove and upgrade any prior versions of Comet Backup, including those with a different software branding.

Silent upgrade (advanced) 

You can silently upgrade the software remotely via the Comet Server interface, or by running /usr/sbin/installer -allowUntrusted -pkg "Comet Backup.pkg" -target / via your remote management software.

Uninstall 

macOS does not have a standard system for uninstalling programs. However, you can still uninstall Comet by running the following command from a terminal window:

sudo -u root "/Applications/Comet Backup.app/Contents/Resources/uninstall"

This will automatically stop all running Comet processes, unregister Comet's launchd services, and remove all application files from the disk.

In Comet 19.12.7 and earlier, the uninstall program was in the MacOS subdirectory instead.

Uninstalling the software preserves any username/password credentials saved on this computer. If you also want to remove the saved username/password credentials, add this command-line:

sudo -u root "/Applications/Comet Backup.app/Contents/Resources/uninstall" --also-remove-saved-passwords

Linux (Debian, Ubuntu) 

Future versions of Comet Backup will provide .deb packages for Debian, Ubuntu, and compatible distributions. In the meantime, you can install Comet Backup using the "Other Distribution" package.

Linux (Red Hat Enterprise Linux (RHEL), CentOS) 

Future versions of Comet Backup will provide .rpm packages for RHEL, CentOS, and compatible distributions. In the meantime, you can install Comet Backup using the "Other distribution" package.

Linux NAS (Synology, QNAP) 

Future versions of Comet will provide integrated packages for Synology and QNAP NAS devices. In the meantime, if you have SSH access to your NAS device, you can install Comet Backup using the "Other distribution" package.

Linux (Other Distribution) 

This is a distribution-agnostic package that can be used if Comet does not have a more specific package available for your Linux distribution.

Please note that in order to avoid distribution-specific differences, the package does not automatically start on boot. You should configure your system to run the launch script in /opt/ on boot (e.g. via a systemd unit, upstart script, /etc/init.d/ script, or a line in init.rc).

System Requirements 

  • CPU: x86_64, or x86_32 with SSE2, or ARM (see below)
  • Kernel 2.6.23 or later
  • Dependencies
    • bash, xz, GNU awk, and standard GNU/Linux system utilities
    • ca-certificates and tzdata (see below)

ARM CPU support 

Comet Backup is available for multiple ARM platform variants. The Comet Backup installer will select the best available binary for your hardware at install-time.

As of Comet 18.8.0, the following platform variants are supported:

Platform Description
ARMv8l ARM 64-bit (Aarch64), no glibc required
ARMv7l ARM 32-bit with vfp, and a glibc-based OS with the "hard-float" ABI (gnueabihf)
ARMv6kl ARM 32-bit with vfp, no glibc required

Timezone database dependency 

Comet Backup on Linux requires the OS to provide an up-to-date timezone database, to perform timezone calculations

  • On many Linux distributions, installing the tzdata or timezone package should be sufficient
  • Otherwise, Comet will look for a timezone database in all of the following locations;
    • /usr/share/zoneinfo
    • /usr/share/lib/zoneinfo
    • /usr/lib/locale/TZ

CA certificate database dependency 

Comet Backup on Linux requires the OS to provide an up-to-date set of root certificate authorities, to validate HTTPS / SSL connections.

  • On many Linux distributions, installing the ca-certificates package should be sufficient
  • Otherwise, Comet will look for a certificate bundle in all of the following locations;
    • /etc/ssl/certs/ca-certificates.crt (used by Debian/Ubuntu/Gentoo etc.)
    • /etc/pki/tls/certs/ca-bundle.crt (used by Fedora/RHEL 6)
    • /etc/ssl/ca-bundle.pem (used by OpenSUSE)
    • /etc/pki/tls/cacert.pem (used by OpenELEC)
    • /etc/pki/ca-trust/extracted/pem/tls-ca-bundle.pem (used by CentOS/RHEL 7)

Install 

Run the .run file. This is a self-extracting archive.

The installer will

  1. install the software into a branded /opt/ subdirectory
  2. prompt you for an initial username and password
  3. register the current Linux device into that Comet account
  4. start running Comet Backup in the background.

If you make a mistake with the username/password prompt, you should follow the below instructions to uninstall the software, and then start the installation again.

Install options 

You can control the installer by setting environment variables in your shell before running the .run file.

The following options are available:

  • WRITE_INSTALL_LOG. Set this to a file path, to record details of the installation.
  • OVERRIDE_INSTALL_SERVER. Set this to a URL (including http/https and trailing slash) to override the Comet Server URL used by Comet Backup.

You can set an environment variable in bash either on the same line (e.g. WRITE_INSTALL_LOG=install.log ./install.run) or as a separate export command (e.g. export WRITE_INSTALL_LOG=install.log followed by ./install.run).

Restarting at boot 

The installer creates a backup-daemon-start.sh script that can start the service. The Comet Backup agent on "Other Distribution" Linux can be restarted by running the backup-daemon-start.sh script.

In order for Comet Backup to start after a system reboot, you must configure this script to be run on system boot. Different Linux distributions support different methods for running commands on system boot: choose the most appropriate method for your Linux distribution. Some common choices are documented below.

Preserve HOME environment variable 

This section does not apply to Comet 19.8.0 and later.

Comet uses the $HOME environment variable to find its saved credentials. When configuring Comet to start at system boot, ensure that the $HOME environment variable is set (i.e. to /root/), to ensure that Comet can find its saved credentials. If Comet is unable to log in, it's possible that your Linux distribution does not set $HOME at this early-boot stage. In that case, you should try running HOME=/root/ /opt/CometBackup/backup-daemon-start.sh & instead.

Start in the background 

If you are running commands over SSH, please be aware that the backup-daemon-start.sh script runs in the foreground and will die when the SSH session is closed. You can avoid this by running the script in the background.

You can run the script in the background (daemonize) by using the backup-daemon-start-background.sh file instead.

Prior to Comet 19.5.0, the backup-daemon-start-background.sh file is not available, and you must daemonize it yourself via nohup / disown / double-fork (e.g. ( cd /opt/CometBackup ; ./backup-daemon-start.sh >/dev/null 2>/dev/null & ) &).

Startup via rc.local 

You can make Comet Backup start at system boot by adding an entry to the rc.local file.

First, find the rc.local file on your system:

  • /etc/rc.local (Debian/Ubuntu)
  • /etc/rc.d/rc.local (CentOS/RHEL)

Add the following content to the rc.local file:

/opt/CometBackup/backup-daemon-start.sh &

If the rc.local file contains an exit 0 statement, the additional command should be added before such a statement.

As of CentOS 7, the rc.local file is not executable by default. You should run chmod +x on the rc.local file to enable using this method for startup scripts.

Startup via rc.d 

You can make Comet Backup start at system boot by adding a file to the rc.d directory.

First, find the rc.d directory on your system:

  • /usr/local/etc/rc.d (Synology DSM 6.1+)

Add a new file to the rc.d directory with the following contents:

#!/bin/bash
/opt/CometBackup/backup-daemon-start-background.sh

Mark the file as executable: chmod +x /usr/local/etc/rc.d/my-comet-startup-script.sh

Startup via cron 

You can make Comet Backup start at system boot by adding an entry to root's crontab.

  1. Run crontab -e -u root to launch a crontab editor
  2. Add the line @reboot /opt/CometBackup/backup-daemon-start-background.sh

Startup via init.d 

No further documentation is available for this topic.

Startup via systemd 

You can use the following unit as an basic example:

[Unit]
Description=Comet Backup Client
After=network-online.target

[Service]
Type=simple
RemainAfterExit=true
User=root
ExecStart=/opt/CometBackup/backup-daemon-start.sh

[Install]
WantedBy=multi-user.target

This unit file correctly starts the Comet Backup service at system boot.

However, the process management in systemd is not fully compatible with the way Comet's multi-process model works. In particular, there are compatibility issues with the software updater. As a result, the above unit is (A) unable to take advantage of process group cleanup; (B) unable to auto-restart the Comet Backup agent service; and (C) after a software upgrade, Comet will keep running but the unit will remain in "exited" state.

A future version of Comet Backup for Linux may change the updater system to work more seamlessly with systemd unit files.

Upgrading 

The "Other Distribution" version of Comet supports upgrading the software, with some caveats:

  • The .run file will automatically upgrade the existing version
  • The software can be remotely upgraded via the Comet Server web interface.

However, the existing service will only be replaced with the upgraded version if the product brand name is unchanged.

Future "Other Distribution" versions of Comet will support upgrading between installations regardless of product brand name.

Uninstall 

To uninstall "Other Distribution" versions of Comet, you should

  1. Stop all Comet processes
  2. Remove the relevant subdirectory under /opt/
  3. Remove any custom startup scripts

Change password on Linux client 

Run backup-tool cmd -Action=change-password -Username USERNAME -Password OLDPASSWORD -Server http://YOURSERVER/ -ExtraData NEWPASSWORD

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