AWS: Newer better workstation user-data

#!/bin/bash


# Please, update this variables with the relevant information

R53_ZONE=<The zone id for your domain, like Z2O1E40J43Y93G>
EMAIL=<Your email>
PASS_PREFIX=<Some very secret prefix for generating passwords>

# Getting the instance name tag

TAG_NAME="Name"
INSTANCE_ID="`wget -qO- http://instance-data/latest/meta-data/instance-id`"
REGION="`wget -qO- http://instance-data/latest/meta-data/placement/availability-zone | sed -e 's:\([0-9][0-9]*\)[a-z]*\$:\\1:'`"
WORKSTATION_NAME="`aws ec2 describe-tags --filters "Name=resource-id,Values=$INSTANCE_ID" "Name=key,Values=$TAG_NAME" --region $REGION --output=text | cut -f5`"

# Updating the system

apt update
apt upgrade -y
snap install core; snap refresh core

# Configuring skel for tmux

wget -P /etc/skel https://gist.githubusercontent.com/ciberado/601b0fad4d3eea3a086124aa68942830/raw/8154c6dfc5429aa7c0bf077fa36c8f259526a366/.tmux.conf
wget -P /etc/skel https://gist.githubusercontent.com/ciberado/601b0fad4d3eea3a086124aa68942830/raw/8154c6dfc5429aa7c0bf077fa36c8f259526a366/.tmux.conf.local

cat << EOF >> /etc/skel/.tmux.conf
set -g status-interval 1
set -g status-right '%H:%M:%S'
EOF

# Creating users

groupadd students
for i in $(seq 1 10); do
  userdel student${i}
  rm -fr /home/student${i}
  useradd -g students -s /bin/bash -m student${i}
  usermod -aG student${i}
  echo "student${i}:${PASS_PREFIX}1234"|chpasswd
done

# Updating R53 with the name of the workstation

PUBLIC_IP=$(curl http://169.254.169.254/latest/meta-data/public-ipv4)
DOMAIN=aprender.cloud

cat << EOF > dns.json
{
   "Changes":[
      {
         "Action":"CREATE",
         "ResourceRecordSet":{
            "Name":"$WORKSTATION_NAME.$DOMAIN",
            "Type":"A",
            "TTL":300,
            "ResourceRecords":[
               {
                  "Value":"$PUBLIC_IP"
               }
            ]
         }
      }
   ]
}
EOF

apt install awscli -y
aws route53 change-resource-record-sets \
  --hosted-zone-id $R53_ZONE \
  --change-batch file://dns.json

sleep 30

# Generating TLS certificates, thanks to Letsencrypt

snap install --classic certbot
ln -s /snap/bin/certbot /usr/bin/certbot

certbot certonly -n --standalone --agree-tos --email $EMAIL -d $WORKSTATION_NAME.aprender.cloud

# Installing ttyd

CERT_PATH=/etc/letsencrypt/live/$WORKSTATION_NAME.$DOMAIN/

wget https://github.com/tsl0922/ttyd/releases/download/1.6.3/ttyd.x86_64
mv ttyd.x86_64 /usr/local/bin/ttyd
chmod +x /usr/local/bin/ttyd

# ttyd -p 443 --ssl --ssl-cert $CERT_PATH/fullchain.pem --ssl-key $CERT_PATH/privkey.pem --ssl-ca $CERT_PATH/chain.pem bash


cat << EOF > /etc/systemd/system/ttyd.service
[Unit]
Description=TTYD
After=syslog.target
After=network.target

[Service]
ExecStart=/usr/local/bin/ttyd -p 443 --ssl --ssl-cert $CERT_PATH/fullchain.pem --ssl-key $CERT_PATH/privkey.pem --ssl-ca $CERT_PATH/chain.pem login
Type=simple
Restart=always
User=root
Group=root

[Install]
WantedBy=multi-user.target
EOF

service ttyd start