Poddery - Diaspora, Matrix and XMPP

We run decentralized and federated Diaspora social netowrk, XMPP and Matrix instant messaging services at poddery.com. Along with Diaspora, Poddery username and password can be used to access XMPP and Matrix services as well. chat.poddery.com provides Riot client (accessed by a web browser), which can be used to connect to any Matrix server without installing a Riot app/client.

Environment

Hosting

Poddery is hosted at Hetzner with the following specs:

• Intel Xeon E3-1246V3 Process - 4 Cores, 3.5GHz
• 4TB HDD
• 32GB DDR3 RAM

Operating System

• Debian Buster

User Visible Services

Diaspora

• Currently installed version is 0.7.6.1 which is available in Debian Buster contrib
• For live statistics see https://poddery.com/statistics

Chat/XMPP

• Prosody is used as the XMPP server which is modern and lightweight.
• Currently installed version is 0.11.2 which is available in Debian Buster.
• All XEPs are enabled which the Conversations app support.

Chat/Matrix

• Synapse is used as the Matrix server.
• Synapse is currently installed directly from the official GitHub repo.
• Riot-web Matrix client is hosted at https://chat.poddery.com

Homepage

Homepage and other static pages are maintained in FSCI GitLab instance.

• poddery.com -> https://git.fosscommunity.in/community/poddery.com
• save.poddery.com -> https://git.fosscommunity.in/community/save.poddery.com
• fund.poddery.com -> https://git.fosscommunity.in/community/fund-poddery

Backend Services

Web Server / Reverse Proxy

• Nginx web server which also acts as front-end (reverse proxy) for Diaspora and Matrix.

Database

• PostgreSQL for Matrix
• MySQL for Diaspora

TODO: Consider migrating to PostgreSQL to optimize resources (We can reduce one service and RAM usage).

Email

• Exim

SSL/TLS certificates

• Let's Encrypt

Firewall

• UFW (Uncomplicated Firewall)

Intrusion Prevention

• Fail2ban

Coordination

• Loomio group - Mainly used for decision making
• Matrix room - #poddery:poddery.com also bridged to xmpp poddery.com-support@chat.yax.im
• Issue tracker - Used for tracking progress of tasks

Contact

• Email: poddery at autistici.org (alias that reaches Akhilan, Abhijith Balan, Fayad, Balasankar, Julius, Praveen, Prasobh, Sruthi, Shirish, Vamsee and Manukrishnan)
• The following people have their GPG keys in the access file:
  • ID: 0xCE1F9C674512C22A - Praveen Arimbrathodiyil (piratepin)
  • ID: 0xB77D2E2E23735427 - Balasankar C
  • ID: 0x5D0064186AF037D9 - Manu Krishnan T V
  • ID: 0x51C954405D432381 - Fayad Fami (fayad)
  • ID: 0x863D4DF2ED9C28EF - Abhijith PA
  • ID: 0x6EF48CCD865A1FFC - Syam G Krishnan (sgk)
  • ID: 0xFD49D0BC6FEAECDA - Sagar Ippalpalli
  • ID: 0x92FDAB42A95FF20C - Pirate Bady (piratesin)
  • ID: 0x0B1955F40C691CCE - Kannan
  • ID: 0x32FF6C6F5B7AE248 - Akhil Varkey
  • ID: 0xFBB7061C27CB70C1 - Ranjith Siji
  • ID: 0xEAAFE4A8F39DE34F - Kiran S Kunjumon (hacksk)
• It's recommended to setup Vim GnuPG Plugin for transparent editing. Those who are new to GPG can follow this guide.

Server Access

Maintained in a private git repo at https://git.fosscommunity.in/community/access

Configuration and Maintenance

Boot into rescue system using https://docs.hetzner.com/robot/dedicated-server/troubleshooting/hetzner-rescue-system

Disk Partitioning

• RAID 1 setup on 2x2TB HDDs (sda and sdb).

mdadm --verbose --create /dev/mdX --level=mirror --raid-devices=2 /dev/sdaY /dev/sdbY

• Separate partitions for swap (md0 - 16GB), boot (md1 - 512MB) and root (md2 - 50GB).
• LVM on Luks for separate encrypted data partitions for database, static files and logs.

# Setup LUKS (make sure lvm2, udev and cryptsetup packages are installed).
cryptsetup luksFormat /dev/mdX
# Give disk encryption password as specified in the access repo
cryptsetup luksOpen /dev/mdX poddery

# LVM Setup
# Create physical volume named poddery
pvcreate /dev/mapper/poddery
# Create volume group named data
vgcreate data /dev/mapper/poddery
# Create logical volumes named log, db and static
lvcreate -n log /dev/data -L 50G
lvcreate -n db /dev/data -L 500G
# Assign remaining free space for static files
lvcreate -n static /dev/data -l 100%FREE 

# Setup filesystem on the logical volumes
mkfs.ext4 /dev/data/log
mkfs.ext4 /dev/data/db
mkfs.ext4 /dev/data/static

# Create directories for mounting the encrypted partitions
mkdir /var/lib/db /var/lib/static /var/log/poddery

# Manually mount encrypted partitions. This is needed on each reboot as Hetzner doesn't provide a web console so that we can't decrypt the partitions during booting.
mount /dev/data/db /var/lib/db
mount /dev/data/static /var/lib/static
mount /dev/data/log /var/log/poddery

Hardening checklist

• SSH password based login disabled (allow only key based logins)
• SSH login disabled for root user (use a normal user with sudo)

# Check for the following settings in /etc/ssh/sshd_config:
...
PermitRootLogin no
...
PasswordAuthentication no
...

• ufw firewall enabled with only the ports that needs to be opened (ufw tutorial):

ufw default deny incoming
ufw default allow outgoing
ufw allow ssh
ufw allow http/tcp
ufw allow https/tcp
ufw allow Turnserver
ufw allow XMPP
ufw allow 8448

ufw enable

# Verify everything is setup properly
ufw status

# Enable ufw logging with default mode low
ufw logging on

• fail2ban configured against brute force attacks:

# Check for the following line /etc/ssh/sshd_config
...
LogLevel VERBOSE
...

# Restart SSH and enable fail2ban
systemctl restart ssh
systemctl enable fail2ban
systemctl start fail2ban

# To unban an IP, first check /var/log/fail2ban.log to get the banned IP and then run the following
# Here sshd is the defaut jail name, change it if you are using a different jail
fail2ban-client set sshd unbanip <banned_ip>

Diaspora

• Install diaspora-installer from Debian Buster contrib:

apt install diaspora-installer

• Move MySQL data to encrypted partition:

# Make sure /dev/data/db is mounted to /var/lib/db
systemctl stop mysql
systemctl disable mysql
mv /var/lib/mysql /var/lib/db/
ln -s /var/lib/db/mysql /var/lib/
systemctl start mysql

• Move static files to encrypted partition:

# Make sure /dev/data/static is mounted to /var/lib/static
mkdir /var/lib/static/diaspora
mv /usr/share/diaspora/public/uploads /var/lib/static/diaspora
ln -s /var/lib/static/diaspora/uploads /usr/share/diaspora/public/
chown -R diaspora: /var/lib/static/diaspora

• Modify configuration files at /etc/diaspora and /etc/diaspora.conf as needed (backup of the current configuration files are available in the access repo).
• Homepage configuration:

# Make sure git and acl packages are installed
# Grant rwx permissions for the ssh user to /usr/share/diaspora/public
setfacl -m "u:<ssh_user>:rwx" /usr/share/diaspora/public

# Clone poddery.com repo
cd /usr/share/diaspora/public
git clone https://git.fosscommunity.in/community/poddery.com.git
cd poddery.com && mv * .[^.]* .. #Give yes for all files when prompted
cd .. && rmdir poddery.com

• Save Poddery repo is maintained as a sub module in poddery.com repo. See this tutorial for working with git submodules.

# Clone save.poddery.com repo
cd /usr/share/diaspora/public/save
git submodule init
git submodule update

Matrix

• See the official installation guide of Synapse for installing from source.
• Nginx is used as reverse proxy to send requests that has /_matrix/* in URL to Synapse on port 8008. This is configured in /etc/nginx/sites-enabled/diaspora.
• Shamil's Synapse Diaspora Auth script is used to authenticate Synapse with Diaspora database.
• Move PostgreSQL data to encrypted partition:

# Make sure /dev/data/db is mounted to /var/lib/db
systemctl stop postgresql
systemctl disable postgresql
mv /var/lib/postgres /var/lib/db/
ln -s /var/lib/db/postgres /var/lib/
systemctl start postgresql

• Move static files to encrypted partition:

# Make sure /dev/data/static is mounted to /var/lib/static
mkdir /var/lib/static/synapse
mv /var/lib/matrix-synapse/uploads /var/lib/static/synapse/
ln -s /var/lib/static/synapse/uploads /var/lib/matrix-synapse/
mv /var/lib/matrix-synapse/media /var/lib/static/synapse/
ln -s /var/lib/static/synapse/media /var/lib/matrix-synapse/
chown -R matrix-synapse: /var/lib/static/synapse

• Install identity server mxisd (deb package available here)

Workers

• For scalability, Poddery is running workers. Currently all workers specified in that page, expect synapse.app.appservice is running on poddery.com
• A new service matrix-synapse@.service is installed for the workers (Save the synape_worker file somewhere like /usr/local/bin/ or something).
• The worker config can be found at /etc/matrix-synapse/workers
• Synapse needs to be put under a reverse proxy see /etc/nginx/sites-enabled/matrix. A lot of /_matrix/ urls needs to be overridden too see /etc/nginx/sites-enabled/diaspora
• These lines must be added to homeserver.yaml as we are running media_repository, federation_sender, pusher, user_dir workers respectively:

 enable_media_repo: False
 send_federation: False
 start_pushers: False
 update_user_directory: false

• These services must be enabled:

matrix-synapse@synchrotron.service matrix-synapse@federation_reader.service matrix-synapse@event_creator.service matrix-synapse@federation_sender.service matrix-synapse@pusher.service matrix-synapse@user_dir.service matrix-synapse@media_repository.service matrix-synapse@frontend_proxy.service matrix-synapse@client_reader.service matrix-synapse@synchrotron_2.service

To load balance between the 2 synchrotrons, We are running matrix-synchrotron-balancer. It has a systemd file at /etc/systemd/system/matrix-synchrotron-balancer. The files are in /opt/matrix-synchrotron-balancer

Synapse Updation

• First check synapse//latest/upgrade to see if anything extra needs to be done. Then, just run /root/upgrade-synapse
• Current version of synapse can be found from https://poddery.com/_matrix/federation/v1/version

Riot-web Updation

• Just run the following (make sure to replace <version> with a proper version number like v1.0.0):

/var/www/get-riot <version>

Chat/XMPP

• Steps for setting up Prosody is given at https://wiki.debian.org/Diaspora/XMPP

# Follow steps 1 to 6 from https://wiki.debian.org/Diaspora/XMPP and then run the following:
mysql -u root -p # Enter password from the access repo

CREATE USER 'prosody'@'localhost' IDENTIFIED BY '<passwd_in_repo>';
GRANT ALL PRIVILEGES ON diaspora_production.* TO 'prosody'@'localhost';
FLUSH PRIVILEGES;

systemctl restart prosody

• Install plugins

# Make sure mercurial is installed
cd /etc && hg clone https://hg.prosody.im/prosody-modules/ prosody-modules

Set Nginx Conf for BOSH URLS

• Add the following in nginx configuration file to enable the BOSH URL to make JSXC Working:

upstream chat_cluster {
  server localhost:5280;
}

location /http-bind {
  proxy_set_header X-Real-IP $remote_addr;
  proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
  proxy_set_header Host $http_host;
  proxy_set_header X-Forwarded-Proto https;
  proxy_redirect off;
  proxy_connect_timeout 5;
  proxy_buffering       off;
  proxy_read_timeout    70;
  keepalive_timeout     70;
  send_timeout          70;
  client_max_body_size 4M;
  client_body_buffer_size 128K;
  proxy_pass http://chat_cluster;
}

• See here for more details on nginx configuration. Alternatively, apache settings can be found here.

TLS

• Install letsencrypt.
• Ensure proper permissions are set for /etc/letsencrypt and its contents.

chown -R root:ssl-cert /etc/letsencrypt
chmod g+r -R /etc/letsencrypt
chmod g+x /etc/letsencrypt/{archive,live}

• Generate certificates. For more details see https://certbot.eff.org.
• Make sure the certificates used by diaspora are symbolic links to letsencrypt default location:

ls -l /etc/diaspora/ssl
total 0
lrwxrwxrwx 1 root root 47 Apr  2 22:47 poddery.com-bundle.pem -> /etc/letsencrypt/live/poddery.com/fullchain.pem
lrwxrwxrwx 1 root root 45 Apr  2 22:48 poddery.com.key -> /etc/letsencrypt/live/poddery.com/privkey.pem

# If you don't get the above output, then run the following:
cp -L /etc/letsencrypt/live/poddery.com/fullchain.pem /etc/diaspora/ssl/poddery.com-bundle.pem
cp -L /etc/letsencrypt/live/poddery.com/privkey.pem /etc/diaspora/ssl/poddery.com.key

• Make sure the certificates used by prosody are symbolic links to letsencrypt default location:

ls -l /etc/prosody/certs/
total 0
lrwxrwxrwx 1 root root 40 Mar 28 01:16 poddery.com.crt -> /etc/letsencrypt/live/poddery.com/fullchain.pem
lrwxrwxrwx 1 root root 33 Mar 28 01:16 poddery.com.key -> /etc/letsencrypt/live/poddery.com/privkey.pem

# If you don't get the above output, then run the following:
cp -L /etc/letsencrypt/live/poddery.com/fullchain.pem /etc/prosody/certs/poddery.com.crt
cp -L /etc/letsencrypt/live/poddery.com/privkey.pem /etc/prosody/certs/poddery.com.key

• Note- letsencrypt executable used below is actually a symlik to /usr/bin/certbot
• Cron jobs:

crontab -e
30 2 * * 1 letsencrypt renew  >> /var/log/le-renew.log
32 2 * * 1 /etc/init.d/nginx reload
34 2 * * 1 /etc/init.d/prosody reload

• Manually updating TLS certificate:

letsencrypt certonly --webroot --agree-tos -w /usr/share/diaspora/public  -d poddery.com -d www.poddery.com -d test.poddery.com -d groups.poddery.com -d fund.poddery.com -w /usr/share/diaspora/public/save -d save.poddery.com -w /var/www/riot -d chat.poddery.com

• To include an additional subdomain such as fund.poddery.com use with --expand parameter as shown below

letsencrypt certonly --webroot --agree-tos --expand -w /usr/share/diaspora/public -d poddery.com -d www.poddery.com -d test.poddery.com -d groups.poddery.com -d fund.poddery.com -w /usr/share/diaspora/public/save/ -d save.poddery.com -w /var/www/riot/ -d chat.poddery.com

Backup

Backup server is provided by Manu (KVM virtual machine with 180 GB storage and 1 GB ram ).

Debian Stetch was upgraded Debian Buster before database relication of synapse database.

Documentation: https://www.percona.com/blog/2018/09/07/setting-up-streaming-replication-postgresql/

Currently postgres database for matrix-synapse is backed up.

Before Replication (specific to poddery.com)

Setup tinc vpn in the backup server

# apt install tinc

Configure tinc by creating tinc.conf and host podderybackup under label fsci. Add tinc-up and tinc-down scripts Copy poddery host config to backup server and podderybackup host config to poddery.com server.

Reload tinc vpn service at both poddery.com and backup servers

# systemctl reload tinc@fsci.service

Enable tinc@fsci systemd service for autostart

# systemctl enable tinc@fsci.service

The synapse database was also pruned to reduce the size before replication by following this guide - https://levans.fr/shrink-synapse-database.html If you want to follow this guide, make sure matrix synapse server is updated to version 1.13 atleast since it introduces the Rooms API mentioned the guide. Changes done to steps in the guide.

 # jq '.rooms[] | select(.joined_local_members == 0) | .room_id' < roomlist.json | sed -e 's/"//g' > to_purge.txt

The room list obtained this way can, be looped to pass the room names as variables to the purge api.

# set +H // if you are using bash to avoid '!' in the roomname triggering the history substitution.
# for room_id in $(cat to_purge.txt); do curl --header "Authorization: Bearer <your access token>" \
   -X POST -H "Content-Type: application/json" -d "{ \"room_id\": \"$room_id\" }" \
   'https://127.0.0.1:8008/_synapse/admin/v1/purge_room'; done;

We also did not remove old history of large rooms.

Step 1: Postgresql (for synapse) Primary configuration

Create postgresql user for replication.

$ psql -c "CREATE USER replication REPLICATION LOGIN CONNECTION LIMIT 1 ENCRYPTED PASSWORD 'yourpassword';"

The password is in the access repo if you need it later.

Allow standby to connect to primary using the user just created.

$ cd /etc/postgresql/11/main

$ nano pg_hba.conf

Add below line to allow replication user to get access to the server

host    replication     replication     172.16.0.3/32   md5

Next , open the postgres configuration file

nano postgresql.conf

Set the following configuration options in the postgresql.conf file

listen_addresses = 'localhost,172.16.0.2'
port=5432
wal_level = replica
max_wal_senders = 1
wal_keep_segments = 64
archive_mode = on
archive_command = 'cd .'

You need to restart since postgresql.conf was edited and parameters changed,

# systemctl restart postgresql

Step 2: Postgresql (for synapse) Standby configuration

Install postgresql

# apt install postgresql

Check postgresql server is running

# su postgres -c psql

Make sure en_US.UTF-8 locale is available

# dpkg-reconfigure locales

Stop postgresql before changing any configuration

#systemctl stop postgresql@11-main

Switch to postgres user

# su - postgres
$ cd /etc/postgresql/11/

Copy data from master and create recovery.conf

$ pg_basebackup -h git.fosscommunity.in -D /var/lib/postgresql/11/main/ -P -U rep --wal-method=fetch  -R

Open the postgres configuration file

$ nano postgresql.conf

Set the following configuration options in the postgresql.conf file

max_connections = 500 // This option and the one below are set to be same as in postgresql.conf at primary or the service won't start.
max_worker_processes = 16
host_standby = on // The above pg_basebackup command should set it. If it's not manually turn it to on.

Start the stopped postgresql service

# systemctl start postgresql@11-main

Postgresql (for synapse) Replication Status

On Primary,

$ ps -ef | grep sender
$ psql -c "select * from pg_stat_activity where usename='rep';"

On Standby,

$ ps -ef | grep receiver

Troubleshooting

Allow XMPP login even if diaspora account is closed

Diaspora has a default setting to close accounts that have been inactive for 2 years. At the time of writing, there seems no way to reopen a closed account. This also means that if your account is closed, you will no longer be able to login to the associated XMPP service as well. Here we discuss a workaround to get access back to the XMPP account.

The prosody module mod_auth_diaspora is used for diaspora-based XMPP auth. It checks if locked_at value in the users table of diaspora db is null here and here. If your account is locked, it will have the datetime value that represents the date and time at which your account is locked. Setting it back to null will let you use your XMPP account again.

-- Replace <username> with actual username of the locked account
UPDATE users SET locked_at=NULL WHERE username='<username>';

NOTE: Matrix account won't be affected even if the associated diaspora account is closed because it uses a custom auth module which works differently.

History

• See here for the archive of Poddery wiki page before the migration to Hetzner.