|Description:||Certbot, from the Let's Encrypt project of the EFF, provides free and automated SSL certificates for QualityBox.|
|Notes:||For non-public sites, we can still generate certificates using DNS|
|Test:||Test on SSL Labs.com|
|Example:||See File:Certificate grade.png|
Certbot is a tool that allows you to manage the Transport Layer Security (TLS) of your Webserver.
Let's Encrypt[edit | edit source]
We used to run certificates from StartSSL because they offer free one-year certificates. However, today we upgraded to using 'LetsEncrypt' and our certificates are both more secure and easier to manage. Instead of a "B" grade, we now have "A" grade security. 
Certbot (code) is a fully-featured, extensible client for the Let's Encrypt CA (or any other CA that speaks the ACME protocol) that can automate the tasks of obtaining certificates and configuring web servers to use them. This client runs on Unix-based operating systems. It requires root access and is beta software.
Until May 2016, Certbot was named simply
letsencrypt-auto, depending on install method. Instructions on the Internet, and some pieces of the software, may still refer to this older name.
Certbot website at EFF.org (the Electronic Frontier Foundation).
Service[edit | edit source]
Using our Ansible role, we can install the certbot client. Then we can install as many certificates as needed; plus setup an automated job which will renew them.
Ansible has a letsencrypt module however, using it is a two-step process. We opted instead to create a more robust Ansible playbook to install and automate certificates.
Current Setup for Meza[edit | edit source]
cd ~/src/ansible-certbot # edit host file as needed, setup DNS as needed # check if the user you expect to use can SSH to the host ssh email@example.com # activate ansible source ~/bin/ansible/hacking/env-setup ansible --version # edit letsencrypt.yml as needed to identify the host for the play ansible-playbook -i hosts letsencrypt.yml # or if you need to use a different user for SSH ansible-playbook -i hosts letsencrypt.yml --user=root # if installing by package (default), then certbot is installed "normally". If by source, it's in /opt/certbot ## on the target host # see if there are any certificates certbot certificates # stop HAProxy to make sure the host is accessible, but don't install into Apache, just use standalone systemctl stop haproxy certbot certonly --standalone -d demo.qualitybox.us # then run meza deploy to concatenate the cert files into a .pem file installed into HAproxy # or if you have to do it manually rm -f /etc/haproxy/certs/meza.key rm -f /etc/haproxy/certs/meza.crt DOMAIN='demo.qualitybox.us' sudo -E bash -c 'cat /etc/letsencrypt/live/$DOMAIN/fullchain.pem /etc/letsencrypt/live/$DOMAIN/privkey.pem > /etc/haproxy/certs/$DOMAIN.pem' # edit HAProxy to use the certificate vim /etc/haproxy/haproxy.cfg systemctl restart haproxy systemctl status haproxy # Now you should be able to access $DOMAIN with a green lock icon
With HAProxy[edit | edit source]
Fortunately, certbot offers a --pre-hook, a --post-hook and a --renew-hook that we can use.
There is even an experimental plugin if you want to go that route, but it's not necessary.
Although a cron like
certbot renew --quiet --no-self-upgrade will work to renew certs, it's not going to install them. So, a better approach is to modify haproxy and also setup a renewal script.
We have to modify the certbot configuration for (each) certificate. Notice how we specified the port at 54321, which we'll use in Haproxy:
# renew_before_expiry = 30 days version = 0.25.1 archive_dir = /etc/letsencrypt/archive/demo.qualitybox.us cert = /etc/letsencrypt/live/demo.qualitybox.us/cert.pem privkey = /etc/letsencrypt/live/demo.qualitybox.us/privkey.pem chain = /etc/letsencrypt/live/demo.qualitybox.us/chain.pem fullchain = /etc/letsencrypt/live/demo.qualitybox.us/fullchain.pem # Options used in the renewal process [renewalparams] account = f47c655802900ba026fb42e0bef8acd7 http01_port = 54321 authenticator = standalone installer = None pref_challs = http-01,
Important parts of the Haproxy configuration. More detail
frontend www-https bind *:443 ssl crt /etc/haproxy/certs reqadd X-Forwarded-Proto:\ https acl letsencrypt-acl path_beg /.well-known/acme-challenge/ use_backend letsencrypt-backend if letsencrypt-acl [snip] backend letsencrypt-backend server letsencrypt 127.0.0.1:54321
#!/bin/sh # instead of manually creating a list like this # declare -a arr=("demo.qualitybox.us" "freephile.qualitybox.us") # loop through a dynamic list of directories in 'live' for SITE in $(ls -D /etc/letsencrypt/live) do # move to correct let's encrypt directory cd /etc/letsencrypt/live/$SITE # echo -e "working in the /etc/letsencrypt/live/$SITE directory\n" # cat files to make combined .pem for haproxy cat fullchain.pem privkey.pem > /etc/haproxy/certs/$SITE.pem # echo -e "created /etc/haproxy/certs/$SITE.pem\n" done # reload haproxy systemctl reload haproxy # echo -e "reloaded haproxy\n"
# use crontab -e as 'root' to setup cron to renew expiring certificates 30 2 * * * /usr/bin/certbot renew --renew-hook "/root/bin/renew.sh" >> /var/log/certbot.log
On Amazon[edit | edit source]
If you're one of the millions of Amazon Web Services customers, you may be tempted to use their lookalike service called AWS Certificate Manager.
AWS certificates can't even be copied between regions. AWS certificates can't be used on your own servers. AWS certificates have annoying limits. They use email in
whois to validate (not going to work if you have domain privacy turned on)!!! Amazon should have just joined the rest of the world in supporting LetsEncrypt. Fortunately, LetsEncrypt can be used everywhere, including AWS.
On Cloudflare[edit | edit source]
Cloudflare offers "Keyless SSL" and "Universal SSL". Although these are excellent signs that Cloudflare is doing good work, it remains true that origin traffic may not be encrypted at all leading to a huge trust problem.
The best way for Cloudflare customers to encrypt fully, is to use Certbot. Cloudflare support echoes word-for-word what Let's Encrypt says in their community forum: How to get a Let's Encrypt certificate while using CloudFlare
tldr; Use the
--webroot-path option with the
certonly --preferred-challenges="dns", but you'll need to manually intervene. Optionally, if you just turn off the proxying while you issue the certificate, you can use TLS-SNI and HTTP-01 challenges (and then turn proxying back on.) For more advanced usage, check out the docs where they describe pre and post validation hooks
With the pre-hook and post-hook options, you can script the conditions needed to authenticate and renew.
certbot renew --pre-hook "service nginx stop" --post-hook "service nginx start"
--renew-hook only runs when a certificate has been successfully renewed, so use this script to do things like concatenate the fullchain and
Resources[edit | edit source]
- https://letsencrypt.org/getinvolved/ Get Involved with Lets Encrypt
- Apache docs
- Ubuntu Server Guide - Certificates and Security
- Ansible role for LetsEncrypt
FAQ[edit | edit source]
- How do I obtain a new certificate?
- setup the SSL virtual host in Apache, and be sure to include some
SSLCertificateKeyFiledirectives using the "snake-oil" certs.
- Then run certbot
/opt/certbot/certbot-auto --apache -d example.org,www.example.org,wiki.example.org --dry-run
/opt/certbot/certbot-auto --apache -d example.org,www.example.org,wiki.example.org
- setup the SSL virtual host in Apache, and be sure to include some
- What certs do I have?
- sudo /opt/certbot/certbot-auto certificates
- How do I see more info about my certificates?
- You can view the 'Security' pane in Chrome Developer Tools, but for quicker access from the command-line, use openssl
sudo openssl x509 -in /etc/haproxy/certs/demo.qualitybox.us.pem -text
keytoolyou can also quickly inspect the certificate of a host:
sudo keytool -printcert -sslserver equality-tech.com
- How do I expand a cert to include some sub-domains? (wildcard certs are not supported)
- sudo /opt/certbot/certbot-auto certonly --cert-name example.org --expand -d example.org,www.example.org,wiki.example.org,example.com,www.example.com,wiki.example.com
- How do I cleanup my old/test certificates?
- sudo /opt/certbot/certbot-auto revoke --cert-path /etc/letsencrypt/live/baz.example.org/cert.pem
- sudo /opt/certbot/certbot-auto delete --cert-name baz.example.org