Thursday, June 01, 2017

SSL termination and http caching with HAProxy, Varnish and Apache

A common requirement when setting up a development or staging server is to try to mimic production as much as possible. One scenario I've implemented a few times is to use Varnish in front of a web site but also use SSL. Since Varnish can't handle encrypted traffic, SSL needs to be terminated before it hits Varnish. One fairly easy way to do it is using HAProxy to terminate both HTTP and HTTPS traffic, then forwarding the unencrypted traffic to Varnish, which then forwards non-cached traffic to Apache or nginx. Here are the steps to achieve this on an Ubuntu 16.04 box.

1) Install HAProxy and Varnish

# apt-get install haproxy varnish

2) Get SSL certificates from Let’s Encrypt

# wget
# chmod +x certbot-auto
# ./certbot-auto -a webroot --webroot-path=/var/www/ -d certonly

3) Generate combined chain + key PEM file to be used by HAProxy

# cat /etc/letsencrypt/live/ /etc/letsencrypt/live/ > /etc/ssl/private/

4) Configure HAProxy

Edit haproxy.cfg and add frontend sections for ports 80 and 443 + backend section pointing to varnish on port 8888

# cat /etc/haproxy/haproxy.cfg
        log /dev/log    local0
        log /dev/log    local1 notice
        chroot /var/lib/haproxy
        stats socket /run/haproxy/admin.sock mode 660 level admin
        stats timeout 30s
        user haproxy
        group haproxy

        # Default SSL material locations
        ca-base /etc/ssl/certs
        crt-base /etc/ssl/private

        # Default ciphers to use on SSL-enabled listening sockets.
        # For more information, see ciphers(1SSL). This list is from:
        ssl-default-bind-options no-sslv3
        tune.ssl.default-dh-param 2048

        log     global
        mode    http
        option  httplog
        option  dontlognull
        timeout connect 5000
        timeout client  50000
        timeout server  50000
        errorfile 400 /etc/haproxy/errors/400.http
        errorfile 403 /etc/haproxy/errors/403.http
        errorfile 408 /etc/haproxy/errors/408.http
        errorfile 500 /etc/haproxy/errors/500.http
        errorfile 502 /etc/haproxy/errors/502.http
        errorfile 503 /etc/haproxy/errors/503.http
        errorfile 504 /etc/haproxy/errors/504.http

frontend www-http
   http-request set-header "SSL-OFFLOADED" "1"
   reqadd X-Forwarded-Proto:\ http
   default_backend varnish-backend

frontend www-https
   bind ssl crt
   http-request set-header "SSL-OFFLOADED" "1"
   reqadd X-Forwarded-Proto:\ https
   default_backend varnish-backend

backend varnish-backend
   redirect scheme https if !{ ssl_fc }
   server varnish check

Enable UDP in rsyslog for haproxy logging by uncommenting 2 lines in /etc/rsyslog.conf:

# provides UDP syslog reception
input(type="imudp" port="514")

Restart rsyslog and haproxy

# service rsyslog restart
# service haproxy restart

5) Configure varnish to listen on port 8888

Ubuntu 16.04 is using systemd for service management. You need to edit 2 files to configure the port varnish will listen on:


In both, set the port after the -a flag to 8888, then stop the varnish service, reload the systemctl daemon and restart the varnish service:

# systemctl stop varnish.service
# systemctl daemon-reload
# systemctl start varnish.service

By default, Varnish will send non-cached traffic to port 8080 on localhost.

6) Configure Apache or nginx to listen on 8080

For Apache, change port 80 to 8080 in all virtual hosts, and also change 80 to 8080 in /etc/apache2/ports.conf.

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