This is a client implementation for ACME (Automatic Certificate Management Environment) protocol, currently draft IETF standard (https://tools.ietf.org/html/draft-ietf-acme-acme-12)
The protocol will be supported by Let's Encrypt project from March 2018. and it is expected that other Certificate Authorities will support this ACME version in the future.
The main idea of this ACME client is to implement as much functionality inside HAProxy. In addition to supporting single instance HAProxy installations, we also aim to support multi-instance deployments (i.e. you have a cluster of load balancers on which you want to use ACME issued certs).
By using the internal HTTP interface (and http client such as curl), you will be able to execute the following:
- Upload your own account and domain keys (only RSA keys for now)
- Automatically register your account on ACME servers (linked to your account key)
- Request and receive certificates for your domains
The only thing you need to do on your own is to save the received certificate bundles and reload HAProxy.
- A modern HAProxy version (v1.8) with Lua support (check with
haproxy -vv | grep USE_LUA=1) - haproxy-lua-http - Lua HTTP server/client for HAProxy Lua host
- json.lua - Lua JSON library
- luaossl - OpenSSL bindings for Lua
Install the required Lua libraries to proper LUA_PATH location, and configure haproxy as follows:
global
log /dev/log local0 debug
nbproc 1
daemon
lua-load config.lua
lua-load acme.lua
defaults
log global
mode http
option httplog
timeout connect 5s
timeout client 10s
timeout server 10s
listen http
bind *:80
http-request use-service lua.acme if { path_beg /.well-known/acme-challenge/ }
listen acme
bind 127.0.0.1:9011
http-request use-service lua.acme
listen acme-ca
bind 127.0.0.1:9012
server ca acme-v02.api.letsencrypt.org:443 ssl verify required ca-file letsencrypt-x3-ca-chain.pem
http-request set-header Host acme-v02.api.letsencrypt.org
Configuration is kept in a separate Lua file, where you must explicitly set
termsOfServiceAgreed option to true in order to be able to acquire
certs. Before doing that, please read latest Let's Encrypt terms of service and
subscriber agreement available at https://letsencrypt.org/repository/
config = {
registration = {
-- You can read TOS here: https://letsencrypt.org/repository/
termsOfServiceAgreed = false,
contact = {"mailto:[email protected]"}
},
-- ACME certificate authority configuration
ca = {
-- HAProxy backend/server which proxies requests to ACME server
proxy_uri = "http://127.0.0.1:9012",
-- ACME server URI (also returned by ACME directory listings)
-- Use this server name in HAProxy config
uri = "https://acme-v02.api.letsencrypt.org",
}
}
Although Lua module is able to create account key or domain automatically, for performance and security reasons we require that you create your keys separately.
Currently, we only support RSA keys. For account key, key size should be 4096bits, and for domain key 2048bits (minimal key sizes are also enforced by Let's Encrypt).
You can use the following commands to create keys. Note that you need a modern
openssl version, we don't use openssl genrsa but openssl genpkey, as
we're going to use the same command to create ECDSA keys in the future.
openssl genpkey -algorithm RSA -pkeyopt rsa_keygen_bits:4096 -out account.key openssl genpkey -algorithm RSA -pkeyopt rsa_keygen_bits:2048 -out example.net.key
After you have provisioned your keys, you can run certificate order via HTTP. For example by using curl to POST data in multipart/form-data format:
curl -XPOST http://127.0.0.1:9011/acme/order -F '[email protected]' \ -F 'domain=example.net' -F '[email protected]' \ -F 'aliases=www.example.net,example.com,www.example.com' \ -o example.net.pem
Aliases are optional, and we use curl @ syntax to post files.
The output is full certificate chain (with key appended), suitable for direct
consumption by HAProxy.