Let's Encrypt certificate renewal with HAProxy

cli.ini

# Use a 4096 bit RSA key instead of 2048
rsa-key-size = 4096

# update to register with the specified e-mail address
email = user@host.com

# use a text interface instead of ncurses
text = True
non-interactive = True
agree-tos = True

# use the standalone authenticator
authenticator = standalone

preferred-challenges = http-01
# this is the same port as in the haproxy letsencrypt backend:
http-01-port = 54321

work-dir = /home/certbot
config-dir = /home/certbot/config
logs-dir = /home/certbot/logs

haproxy.cfg

# just the relevant parts
frontend http
  # ...
  
  # direct all letsencrypt requests to a special backend
  acl letsencrypt-acl path_beg /.well-known/acme-challenge/
  use_backend letsencrypt-backend if letsencrypt-acl
  
# this backend will forward to the letsencrypt validation server
# that is fired up automatically during certificate creation / renewal
# in certbot's standalone mode
backend letsencrypt-backend
  server letsencrypt 127.0.0.1:54321

le-haproxy-bundle

#!/bin/bash

domain=$1

fullchain_file="/home/certbot/certs/$domain/fullchain.pem"
key="/home/certbot/certs/${domain}/${domain}.key"
combined_file="/etc/haproxy/ssl/${domain}.pem"
dhparam="/home/certbot/dhparam"

if [ ! -f $key ]; then
  key="/home/certbot/letsencrypt.key"
fi

if [ -f $fullchain_file -a -f $key -a -f $dhparam ]
then

  if [ -f $combined_file ]
  then
    cp $combined_file "${combined_file}.old"
  fi

  cat $fullchain_file $key $dhparam > $combined_file
  chmod 0400 $combined_file
fi

le-renew-haproxy

#!/bin/bash

reload_required=false

# attempt to renew when less then 30 days remaining
exp_limit=30;

# returns 0 if no renewal needed, 1 otherwise
check_cert_still_valid () {
  local cert_file=$1

  local exp=$(date -d "`openssl x509 -in $cert_file -text -noout|grep "Not After"|cut -c 25-`" +%s)
  local datenow=$(date -d "now" +%s)
  local days_exp=$(echo \( $exp - $datenow \) / 86400 |bc)

  echo "Checking expiration date for $domain..."

  if [ "$days_exp" -gt "$exp_limit" ] ; then
    echo "The certificate is up to date, no need for renewal ($days_exp days left)."
    return 0
  else
    echo "The certificate $cert_file is about to expire soon. Starting renewal..."
    return 1
  fi
}


get_certificate() {

  local domain=$1
  local cert_file=$2

  local key_file="/home/certbot/certs/${domain}/${domain}.key"
  local csr_file="/home/certbot/certs/${domain}/${domain}.csr"

  local chain_file="/home/certbot/certs/$domain/chain.pem"
  local fullchain_file="/home/certbot/certs/$domain/fullchain.pem"

    # Certbot refuses to overwrite existing files, so remove anything that
    # might get in the way.
    # The certificate used by haproxy is kept separately, so no harm is done by
    # deleting these files:
    rm -f $cert_file $chain_file $fullchain_file
    certbot certonly --csr $csr_file --cert-path $cert_file --chain-path $chain_file --fullchain-path $fullchain_file

    if [ $? -eq 0 ]; then

      echo "Creating $combined_file with latest certs..."
      sudo /usr/local/sbin/le-haproxy-bundle $domain

      echo "Renewal process finished for domain $domain"
      reload_required=true

    else

      echo "certbot failed, not replacing installed certificate for ${domain}"

    fi
}

process_certificate() {
  local domain=$1
  local cert_file="/home/certbot/certs/$domain/${domain}.crt"

  if [ -f $cert_file ]; then

    check_cert_still_valid $cert_file

    if [ ! $? -eq 0 ]; then
      get_certificate $domain $cert_file
    fi

  else

    echo "No certificate for domain $domain exists yet. Creating one..."
    get_certificate $domain $cert_file

  fi
}




domain=$1

# loop over all domains unless a domain is given
if [ "${domain}" = "" ]; then

  for i in $( ls /home/certbot/certs ); do
    process_certificate $i
  done

else

  process_certificate $domain

fi


if [ "$reload_required" = true ]; then

  echo "Reloading haproxy"
  sudo /usr/sbin/service haproxy reload

fi