ITSquad/Server setup

This page aims to list the operations needed when we want to create or migrate a server.

Create a new VM

1. Order a new VM at Hetzner: https://console.hetzner.cloud
2. Click on the button Add a new server
3. Select the location, OS, and the resources needed
4. Add the ssh public keys that will be able to access the server
5. Name the server after a character from One Piece
6. Go to metaregistrar to setup the DNS: https://control.metaregistrar.com/login

You should be able to connect in root with your ssh key:

 ssh root@<ip address or hostname> -i ~/.ssh/<private key>

SSH

1. Edit the sshd config: vim /etc/ssh/sshd_config
2. Change the port used by ssh server
3. Allow root login with public keys only: PermitRootLogin prohibit-password
4. Restart the ssh server: systemctl restart ssh

Firewall

Install and setup ufw, an easy to use firewall manager:

 apt install ufw
 ufw allow <ssh port>
 ufw allow "Nginx Full" # only if nginx is installed
 ufw enable

Storage Box

Configure access to the storage box for backups and media storage:

1. Generate the ssh key to access the storage box: ssh-keygen -t ed25519 -f ~/.ssh/storage-box
2. Configure ssh: vim ~/.ssh/config. Enter the following:

 Host <storage box hostname>
 User <username>
 Port 23
 IdentityFile ~/.ssh/storage-box
 PreferredAuthentications publickey,password

where <username> is the sub-account username for the storage box. For the storage box hostname, refer to our password store.

Finally, add your ssh key to the storage box: ssh-copy-id -i ~/.ssh/storage-box <storage box hostname>. You should be asked for the storage box's password.

Autofs

In case you need to mount the storage box:

1. Install autofs and sshfs: apt install autofs sshfs
2. Edit /etc/auto.master, and add the line: /mnt/storage-box /etc/auto.sshfs --timeout=90,--ghost
3. Create /etc/auto.sshfs with this content: backup -fstype=fuse,rw :sshfs\#<storage box hostname>\:/home/backup
4. Optionaly, add a line for mounting media directory: media -fstype=fuse,rw,allow_other :sshfs\#<storage box hostname>\:/home/media

Backups

Install and configure duplicity to backup the server. We encrypt the backups with a public/private key pair that we generate for this server. Duplicity needs to know the private key in order to compute the difference between the current state of the directory to backup and the last backup.

Requirements

Install duplicity, paramiko and gpg:

 apt install duplicity gpg python-pip python-setuptools && pip install -U paramiko

Credentials

Generate for the server a new key pair with a random passphrase, then import public keys to allow trusted people to decrypt the backups when needed.

Generate a key pair

1. Create a file that will store the passphrase: touch /root/gpg-duplicity.secret && chmod 600 /root/gpg-duplicity.secret
2. Generate the passphrase: openssl rand -base64 42 > /root/gpg-duplicity.secret
3. Generate a GPG key pair: gpg --quick-gen-key <your email> ed25519 cert 0. You'll be asked to enter twice the passphrase that you've generated.
4. Edit this GPG key pair to add a sub-key for encryption: gpg --edit-key <key id>. Then, enter addkey, and choose a RSA key for encryption (option #6). Enter save to quit.

Note: Don't forget to add the GPG key id with the passphrase in our password store.

Import public keys

1. On your local machine, generate a key pair (or reuse one of yours) and export it to a file: gpg -a --export <key id> > <key file.pub>
2. Copy this key on the server: scp <key file.pub> root@<your server>:~/
3. Import the key: gpg --import /root/<key file.pub>
4. Trust the key: gpg --edit-key <key id>. Enter trust, choose I trust ultimately then quit.

Configuration

Create a script file with the following content:

 #!/bin/bash
 
 BACKUP_NAME=daily_<service name>_backup
 GPG_KEYS="<key id 1> [<key id 2> ...]"
 PASSPHRASE_FILE=/root/gpg-duplicity.secret
 RETRIES=3
 PERIOD_FULL_BACKUP=1M
 MAX_FULL_BACKUPS=2
 
 EXCLUDES=
 SOURCE=/dir/to/backup
 TARGETS="sftp://<target hostname 1>/path/to/backup sftp://<target hostname 2>/path/to/backup"
 
 export PASSPHRASE=$(/bin/cat "$PASSPHRASE_FILE")
 
 GPG_KEYS=$(for key in $GPG_KEYS; do echo -n "--encrypt-key $key "; done)
 EXCLUDES=$(for exclude in $EXCLUDES; do echo -n "--exclude $exclude "; done)
 
 for TARGET in $TARGETS; do
   TARGET_DOMAIN=$(cut -d '/' -f 3 <<< "$TARGET")
   BACKUP_NAME_TARGET="${BACKUP_NAME}_${TARGET_DOMAIN}"
 
   duplicity --full-if-older-than $PERIOD_FULL_BACKUP \
     $GPG_KEYS \
     --name $BACKUP_NAME_TARGET \
     --num-retries $RETRIES \
     $EXCLUDES \
     $SOURCE $TARGET && \
   duplicity remove-all-but-n-full $MAX_FULL_BACKUPS --force --name $BACKUP_NAME_TARGET $TARGET
 done

Then, create a cron task:

 crontab -e
 @daily /root/<backup.sh> > /dev/null