/spark

Arch Linux Provisioning with Ansible

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Spark

Spark is an Ansible playbook meant to provision a personal machine running Arch Linux. It is intended to run locally on a fresh Arch install (ie, taking the place of any post-installation), but due to Ansible's idempotent nature it may also be run on top of an already configured machine.

Spark assumes it will be run on a laptop and performs some configuration based on this assumption. This behaviour may be changed by removing the laptop role from the playbook or by skipping the laptop tag.

If Spark is run on either a ThinkPad or a MacBook, it will detect this and execute platform-specific tasks.

Note: If you would like to try recreating all the tasks that are currently included in the ansible playbook, through a VM, you would need a disk of at least 16GB in size.

Running

First, sync mirrors and install Ansible:

$ pacman -Syy python-passlib ansible

Second, install and update the submodules:

$ git submodule init && git submodule update

Run the playbook as root.

# ansible-playbook -i localhost playbook.yml

When run, Ansible will prompt for the user password. This only needs to be provided on the first run when the user is being created. On later runs, providing any password -- whether the current user password or a new one -- will have no effect.

SSH

By default, Ansible will attempt to install the private SSH key for the user. The key should be available at the path specified in the ssh.user_key variable. Removing this variable will cause the key installation task to be skipped.

SSHD

If ssh.enable_sshd is set to True the systemd socket service will be enabled. By default, sshd is configured but not enabled.

Dotfiles

Ansible expects that the user wishes to clone dotfiles via the git repository specified via the dotfiles.url variable and install them with rcm. The destination to clone the repository to is defined by the dotfiles.destination variable. This is relative the user's home directory.

These tasks will be skipped if the dotfiles variable is not defined.

Tagging

All tasks are tagged with their role, allowing them to be skipped by tag in addition to modifying playbook.yml.

AUR

All tasks involving the AUR are tagged aur. To provision an AUR-free system, pass this tag to ansible's --skip-tag.

AUR packages are installed via the ansible-aur module. Note that while yay, an AUR helper, is installed by default, it will not be used during any of the provisioning.

Firejail

Many applications are sandboxed with Firejail. This behavior should be largely invisible to the user.

Custom security profiles are provided for certain applications. These are installed to /usr/local/etc/firejail. Firejail does not look in this directory by default. To use the security profiles, they must either be specified on the command-line or included in an appropriately named profile located in ~/.config/firejail.

# Example 1:
# Launch Firefox using the custom profile by specifying the full path of the profile.
$ firejail --profile=/usr/local/etc/firejail/firefox.profile /usr/bin/firefox
# Example 2:
# Launch Firefox using the custom profile by specifying its directory.
$ firejail --profile-path=/usr/local/etc/firejail /usr/bin/firefox
# Example 3:
# Include the profile  in ~./config/firejail
$ mkdir -p ~/.config/firejail
$ echo 'include /usr/local/etc/firejail/firefox.profile' > ~/.config/firejail/firefox.profile
$ firejail /usr/bin/firefox

The script profile-activate is provided to automatically include the profiles when appropriate. For every profile located in /usr/local/etc/firejail, the script looks for a profile with the same name in ~/.config/firejail. If one is not found, it will create a profile that simply includes the system profile, as in the third example above. It will not modify any existing user profiles.

Blacklisting

The firejail.blacklist variable is used to populate /etc/firejail/globals.local with a list of blacklisted files and directories. This file is included by all security profiles, causing the specified locations to be inaccessible to jailed programs.

MAC Spoofing

By default, the MAC address of all network interfaces is spoofed at boot, before any network services are brought up. This is done with macchiato, which uses legitimate OUI prefixes to make the spoofing less recognizable.

MAC spoofing is desirable for greater privacy on public networks, but may be inconvenient on home or corporate networks where a consistent (if not real) MAC address is wanted for authentication. To work around this, allow macchiato to randomize the MAC on boot, but tell NetworkManager to clone the real (or a fake but consistent) MAC address in its profile for the trusted networks. This can be done in the GUI by populating the "Cloned MAC address" field for the appropriate profiles, or by setting the cloned-mac-address property in the profile file at /etc/NetworkManager/system-connections/.

Spoofing may be disabled entirely by setting the network.spoof_mac variable to False.

Trusted Networks

The trusted network framework provided by nmtrust is leveraged to start certain systemd units when connected to trusted networks, and stop them elsewhere.

This helps to avoid leaking personal information on untrusted networks by ensuring that certain network tasks are not running in the background. Currently, this is used for mail syncing (see the section below on Syncing and Scheduling Mail), Tarsnap backups (see the section below on Scheduling Tarsnap), BitlBee (see the section below on BitlBee), and git-annex (see the section below on git-annex).

Trusted networks are defined using their NetworkManager UUIDs, configured in the network.trusted_uuid list. NetworkManager UUIDs may be discovered using nmcli con.

Mail

Receiving Mail

Receiving mail is supported by syncing from IMAP servers via both isync and OfflineIMAP. By default isync is enabled, but this can be changed to OfflineIMAP by setting the value of the mail.sync_tool variable to offlineimap.

Sending Mail

msmtp is used to send mail. Included as part of msmtp's documentation are a set of msmtpq scripts for queuing mail. These scripts are copied to the user's path for use. When calling msmtpq instead of msmtp, mail is sent normally if internet connectivity is available. If the user is offline, the mail is saved in a queue, to be sent out when internet connectivity is again available. This helps support a seamless workflow, both offline and online.

System Mail

If the email.user variable is defined, the system will be configured to forward mail for the user and root to this address. Removing this variable will cause no mail aliases to be put in place.

The cron implementation is configured to send mail using msmtp.

Syncing and Scheduling Mail

A shell script called mailsync is included to sync mail, by first sending any mail in the msmtp queue and then syncing with the chosen IMAP servers via either isync or OfflineIMAP. The script will also attempt to sync contacts and calendars via vdirsyncer. To disable this behavior, set the mail.sync_pim variable to False.

Before syncing, the mailsync script checks for internet connectivity using NetworkMananger. mailsync may be called directly by the user, ie by configuring a hotkey in Mutt.

A systemd timer is also included to periodically call mailsync. The timer is set to sync every 5 minutes (configurable through the mail.sync_time variable).

The timer is not started or enabled by default. Instead, the timer is added to /etc/nmtrust/trusted_units, causing the NetworkManager trusted unit dispatcher to activate the timer whenever a connection is established to a trusted network. The timer is stopped whenever the network goes down or a connection is established to an untrusted network.

To have the timer activated at boot, change the mail.sync_on variable from trusted to all.

If the mail.sync_on variable is set to anything other than trusted or all, the timer will never be activated.

Tarsnap

Tarsnap is installed with its default configuration file. However, setting up Tarsnap is left as an exercise for the user. New Tarsnap users should register their machine and generate a key. Existing users should recover their key(s) and cache directory from their backups (or, alternatively, recover their key(s) and rebuild the cache directory with tarsnap --fsck).

Tarsnapper is installed to manage backups. A basic configuration file to backup /etc is included. Tarsnapper is configured to look in /usr/local/etc/tarsnapper.d for additional jobs. As with with the Tarsnap key and cache directory, users should recover their jobs files from backups after the Tarsnapper install is complete. See the Tarsnapper documentation for more details.

Running Tarsnap

A systemd unit file and timer are included for Tarsnapper. Rather than calling it directly, the systemd unit wraps Tarsnapper with backitup.

The timer is set to execute the unit hourly, but backitup will only call Tarsnapper once within the period defined in the tarsnapper.period variable. This defaults to DAILY. This increases the likelyhood of completing daily backups by checking each hour if the unit has run succesfully on the current calendar day.

In addition to the period limitation, backitup defaults to only calling Tarsnapper when it detects the machine ison AC power. To allow Tarsnapper to run when on battery, set the tarsnapper.ac_only variable to False.

As with mailsync, the timer is not started or enabled by default. Instead, the timer is added to /etc/nmtrust/trusted_units, causing the NetworkManager trusted unit dispatcher to activate the timer whenever a connection is established to a trusted network. The timer is stopped whenever the network goes down or a connection is established to an untrusted network.

To have the timer activated at boot, change the tarsnapper.run_on variable from trusted to all.

If the tarsnapper.run_on variable is set to anything other than trusted or all, the timer will never be activated.

Tor

Tor is installed by default. A systemd service unit for Tor is installed, but not enabled or started. instead, the service is added to /etc/nmtrust/trusted_units, causing the NetworkManager trusted unit dispatcher to activate the service whenever a connection is established to a trusted network. The service is stopped whenever the network goes down or a connection is established to an untrusted network.

To have the service activated at boot, change the tor.run_on variable from trusted to all.

If you do not wish to use Tor, simply remove the tor variable from the configuration.

parcimonie.sh

parcimonie.sh is provided to periodically refresh entries in the user's GnuPG keyring over the Tor network. The service is added to /etc/nmtrust/trusted_units and respects the tor.run_on variable.

BitlBee

BitlBee and WeeChat are used to provide chat services. A systemd service unit for BitlBee is installed, but not enabled or started by default. Instead, the service is added to /etc/nmtrust/trusted_units, causing the NetworkManager trusted unit dispatcher to activate the service whenever a connection is established to a trusted network. The service is stopped whenever the network goes down or a connection is established to an untrusted network.

To have the service activated at boot, change the bitlbee.run_on variable from trusted to all.

If the bitlbee.run_on variable is set to anything other than trusted or all, the service will never be activated.

By default BitlBee will be configured to proxy through Tor. To disable this, remove the bitlebee.torify variable or disable Tor entirely by removing the tor variable.

git-annex

git-annex is installed for file syncing. A systemd service unit for the git-annex assistant is enabled and started by default. To prevent this, remove the gitannex variable from the config.

Additionally, the git-annex unit is added to /etc/nmtrust/trusted_units, causing the NetworkManager trusted unit dispatcher to activate the service whenever a connection is established to a trusted network. The service is stopped whenever a connection is established to an untrusted network. Unlike other units using the trusted network framework, the git-annex unit is also activated when there are no active network connections. This allows the git-annex assistant to be used when on trusted networks and when offline, but not when on untrusted networks.

If the gitannex.stop_on_untrusted variable is set to anything other than True or is not defined, the git-annex unit will not be added to the trusted unit file, resulting in the git-annex assistant not being stopped on untrusted networks.

PostgreSQL

PostgreSQL is installed and enabled by default. If the postgresql.enable variable is set to anything other than True or is not defined, the service will not be started or enabled.

This is intended for local development. PostgreSQL is configured to only listen on localhost and no additional ports are opened in the default firewall. This configuration means that PostgreSQL is not a network service. As such, the PostgreSQL service is not added to /etc/nmtrust/trusted_units.

Additional configuration options are set which improve performance but make the database service inappropriate for production use.

Himawaripy

Himawaripy is provided to fetch near-realtime photos of Earth from the Japanese Himawari 8 weather satellite and set them as the user's desktop background via feh. This should provide early warning of the presence of any Vogon constructor fleets appearing over the Eastern Hemisphere.

A systemd service unit and timer is installed, but not enabled or started by default. Instead, the service is added to /etc/nmtrust/trusted_units, causing the NetworkManager trusted unit dispatcher to activate the service whenever a connection is established to a trusted network. The service is stopped whenever the network goes down or a connection is established to an untrusted network.

To have the service activated at boot, change the himawaripy.run_on variable from trusted to all.

If the himawaripy.run_on variable is set to anything other than trusted or all, the service will never be activated.

By default the timer is scheduled to fetch a new image at 15 minute intervals. This can be changed by modifying the himawaripy.run_time variable.

By completely removing the himawaripy variable, no related tasks will be run.