Poddery - Diaspora, Matrix and XMPP

We run diaspora, xmpp and matrix services at poddery.com. Diaspora username and password can be used to access xmpp and matrix services. 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

We are on a C2S instance of scaleway.com bare metal cloud server.

• 4 Dedicated x86 64bit Cores
• 8GB Memory
• 50GB SSD Disk
• 1 Flexible public IPv4
• 300Mbit/s Unmetered bandwidth
• 2.5Gbit/s Internal bandwidth
• €11.99 Per month

Due to performance issues we are migrating to a new server (C2M instance of scaleway.com) with the following specs:

• 8 Dedicated x86 64bit Cores
• 16GB Memory
• 50GB SSD Disk
• 1 Flexible public IPv4
• 500Mbit/s Unmeterd bandwidth
• 5Gbit/s Internal bandwidth
• €17.99 per month

Operating System

We run debian 9 stretch image provided by scaleway.

Hardening checklist

• SSH password login disabled (allow only key based logins)
• root SSH login disabled (use a normal user with sudo)
• Firewall enabled with only the ports we need opened
• fail2ban configured against brute force attacks

System health check

• There should be a data disk attached (added from cloud.scaleway.com)
• The attached disk (/dev/nbd2) should be an lvm physical volume (pvcreate /dev/nbd2). We cannot use it directly for encryption, so we use lvm.
• /dev/data is an lvm volume group created from /dev/nbd2 (vgcreate data /dev/nbd2).
• /dev/data/diaspora is an lvm logical volume (lvcreate -n diaspora /dev/data -L 93.5G).
• /dev/mapper/diaspora is an encrypted device (cryptsetup luksFormat /dev/data/diaspora; cryptsetup luksOpen /dev/data/diaspora diaspora)
• /dev/mapper/diaspora is an ext4 file system (mkfs.ext4 /dev/mapper/diaspora)
• /var/lib/diaspora should be mounted (mount /dev/mapper/diaspora /var/lib/diaspora)
• all critical data should be on /var/lib/diaspora.

/etc/init.d/mysql stop; mv /var/lib/mysql /var/lib/diaspora; ln /var/lib/diaspora/mysql /var/lib/diaspora mkdir /var/lib/diaspora/uploads; chown -R diaspora: /var/lib/diaspora/uploads;ln -s /var/lib/diaspora/uploads /usr/share/diaspora/public/uploads

Services health check

 systemctl status nginx # our web server front end for diaspora, xmpp and matrix
 systemctl status diaspora # diaspora service
 systemctl status matrix-synapse.service # synapse matrix server
 systemctl status prosody # prosody xmpp server
 systemctl status sslh # SSL/SSH multiplexer which allow us to provide multiple services via 443 port (to bypass stupid firewalls)

User Visible Services

Homepage

Homepage and other static pages are maintained in our gitlab instance. You can change it directly in the master branch or send pull requests. You can edit it via web as well.

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

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

save.poddery.com repo is maintained as a sub module in poddery.com repo. See this tutorial -> https://chrisjean.com/git-submodules-adding-using-removing-and-updating/ for working with git submodules.

SSL/TLS certificates

# letsencrypt certonly --webroot -w /usr/share/diaspora/public  -d poddery.com -d www.poddery.com -d test.poddery.com -d groups.poddery.com -w /usr/share/diaspora/public/save -d save.poddery.com
# 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
# chown -R root:ssl-cert /etc/letsencrypt
# chmod g+r -R /etc/letsencrypt
# chmod g+x /etc/letsencrypt/*

# 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

# 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

Diaspora

We use diaspora-installer-mysql package from https://people.debian.org/~praveen/diaspora (stretch/contrib) See /usr/share/doc/diaspora-common/README for package specific configuration.

• live statistics

Chat/XMPP

• We use prosody and steps for setting up prosody is given at -> https://wiki.debian.org/Diaspora/XMPP
• We have enabled all XEPs conversations expect. We use sslh to multiplex diaspora and prosody on port 443.

Chat/Matrix

• We use synapse server for setting up the matrix server.
• We will be using https://github.com/matrix-org/synapse/#synapse-installation for setting up this instance
• We use nginx reverse proxy to send requests that has /_matrix/* in url to synapse on 8008. See /etc/nginx/sites-enabled/diaspora

Backend Services

nginx

Front end for diaspora and matrix.

PostgreSQL

Backend for matrix.

MySQL

Backend for diaspora. TODO: consider migrating to PostgreSQL to optimize resources (we can reduce one service and RAM usage).

sslh

Port multiplexer to allow xmpp and diaspora to share 443 port. This allows us to fool stupid firewalls which blocks all ports except 80 and 443 (hence xmpp).

Coordination

• loomio group - we use this for decision making.
• Hangout with us in our matrix room #poddery:poddery.com

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 password file.

Praveen Arimbrathodiyil (piratepin) (ID: 0xCE1F9C674512), Balasankar C (ID: 0x96EDAB9B2E6B7171), Manu Krishnan T V (ID: 0x5D0064186AF037D9), Fayad Fami (fayad) (ID: 0x51C954405D432381), Abhijith PA (ID: 0x863D4DF2ED9C28EF), Syam G Krishnan (sgk) (ID: 0x6EF48CCD865A1FFC), Sagar Ippalpalli (ID: 0xFD49D0BC6FEAECDA)

We recommend you setup vim gpg plugin for transparent editing. If you are new to gpg, then follow this guide.

Server Access

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

Setting up Backup

Backup was setup on a Scaleway C1 VPS (4 core ARM processor with 2GB RAM). TODO: C1 server was crashing frequently and we need to setup backup again on VPS provided by Manu.

Hostname (IP): backup.poddery.com (No public ip, access via scaleway.com web console). If you restart this machine, you may want to add poddery.com private ip in /etc/hosts

# apt-get install lvm2 cryptsetup

Directly creating luks volume on /dev/nbd1 is not working, so we use a logical volume

# pvcreate /dev/nbd1
# vgcreate data /dev/nbd1
# lvcreate -n diaspora -L 46.5G /dev/data

# cryptsetup luksFormat /dev/data/diaspora
# cryptsetup luksOpen /dev/data/diaspora diaspora

and update /etc/crypttab

# <target name> <source device>         <key file>      <options>
diaspora /dev/data/diaspora none luks

# mkfs.ext4 /dev/mapper/diaspora
# mkdir /var/lib/diaspora

and update /etc/fstab

# UNCONFIGURED FSTAB FOR BASE SYSTEM
/dev/mapper/diaspora /var/lib/diaspora ext4 defaults 0 2

# mount -a
# apt-get install mysql-server

Move mysql data directory to encrypted volume

# /etc/init.d/mysql stop
# mv /var/lib/mysql /var/lib/diaspora/
# ln -s /var/lib/diaspora/mysql /var/lib/mysql

Follow steps in https://dev.mysql.com/doc/refman/5.5/en/replication-howto-masterbaseconfig.html for replication

Follow steps in https://www.howtoforge.com/how-to-set-up-mysql-database-replication-with-ssl-encryption-on-centos-5.4 for ssl (but ssl support is disabled in debian)

Follow steps in http://www.networkcomputing.com/storage/how-set-ssh-encrypted-mysql-replication/1111882674 to use ssh port forwarding to have encrypted replication

# adduser sshtunnel --disabled-login
# su sshtunnel

Generate ssh key pair and copy public key to target system

$ ssh-keygen -t rsa
$ ssh -f sshtunnel@poddery.com -L 7777:127.0.0.1:3306 -N

Test the connectivity

# mysql -u poddery_backup -p -P 7777 -h 127.0.0.1

Uploads are rsynced every hour

# crontab -e
# m h  dom mon dow   command
0 * * * * pgrep rsync || rsync -av --delete root@poddery.com:/var/lib/diaspora/uploads/ /var/lib/diaspora/uploads/ >/var/lib/diaspora/rsync-uploads.log

Note: Since we are not using a public ip (saves us money), backup.poddery.com connects to poddery.com via private ip. So if poddery.com is rebooted, the new ip address should be updated in /etc/hosts file of backup.poddery.com. To connect, use the web console from scaleway.com

Add more disk space

1. Power off the machine with "ARCHIVE" option. It may take upto an hour for shutdown to complete on backup.poddery.com and poddery.com
2. Add more disk from scaleway.com control panel . Volumes -> CREATE VOLUME
3. Attach the newly created volume to server from Server page
4. Power on the server
5. Create physical volume (pvcreate /dev/nbdN)
6. Expand volume group (vgextend data /dev/nbdN)
7. Expand logical volume (lvresize --size=186G data/diaspora)
8. Expand encrypted partition (cryptsetup resize diaspora)
9. Resize file system (resize2fs /dev/mapper/diaspora)

Maintenance history

This section holds maintenance/issue history for future tracking.

When updating diaspora-installer-mysql packages, remember to recreate /usr/share/diaspora/public/uploads symlink to /var/lib/diaspora/uploads.

1. Prosody error - Failed to load private key

certmanager error SSL/TLS: Failed to load '/etc/letsencrypt/live/poddery.com/privkey.pem': Previous error (see logs), or other system error. (for poddery.com)
tls error   Unable to initialize TLS: error loading private key (system lib)
certmanager error SSL/TLS: Failed to load '/etc/letsencrypt/live/poddery.com/privkey.pem': Check that the permissions allow Prosody to read this file.

This error is usually when ssl certificate in freshly installed or renewed. Prosody user is unable to access the key file due to lack of privileges.

Note that Poddery uses Letsencrypt for ssl.

Fix:

• Make sure that prosody user is in 'certs' group (this group may also be called ssl-certs as setup by Letencrypt)
• /etc/letsencrypt/ is the ssl directory.
• Prosody user should have permissions to all folders importantly archive and live folders in /etc/letsencrypt. Permissions to each folder must be 750.
• Troubleshoot by checking if you can switch to each folder in /etc/letsencrypt as prosody user and cat the files.

If replication fails, you can restart it following the instructions here

https://dba.stackexchange.com/questions/69394/mysql-replication-error-1594