What is HAProxy?

  • Load balancer written in C
  • Available on most Unix distributions
  • Allow to balance traffic and avoid downtime in case of failure

HAProxy configuration file

  • Located in /etc/haproxy/haproxy.conf
  • Can be checked with haproxy -c -f /etc/haproxy/haproxy.cfg
  • Restart to apply a new configuration with service haproxy restart

HAProxy configuration

global bloc

global
        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
        daemon

        # 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).
        ssl-default-bind-ciphers kEECDH+aRSA+AES:kRSA+AES:+AES256:RC4-SHA:!kEDH:!LOW:!EXP:!MD5:!aNULL:!eNULL

HAProxy configuration

defaults bloc

defaults
        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

HAProxy configuration

frontend bloc

frontend localnodes
    bind *:80
    mode http
    default_backend nodes

    acl is_other_site hdr(host) -i www.my-other-site.com
    use_backend nodes2 if is_other_site

HAProxy configuration

backend bloc

backend nodes
    mode http
    balance roundrobin
    option httpchk HEAD / HTTP/1.1\r\nHost:localhost
    server web01 127.0.0.1:9000 check
    server web02 127.0.0.1:9001 check
    server web03 127.0.0.1:9002 check

backend nodes2
    mode http
    balance roundrobin
    option httpchk HEAD / HTTP/1.1\r\nHost:localhost
    default-server inter 2s fall 3 rise 2
    server-template nodes 3 _website2._http.service.consul check resolvers my-resolvers resolve-opts allow-dup-ip resolve-prefer ipv4

HAProxy configuration

listen bloc

listen stats *:1936
    stats enable
    stats uri /
    stats show-node
    stats show-desc
    stats show-legends
    stats auth someuser:password

HAProxy configuration

resolvers bloc

resolvers my-resolvers
    nameserver consul01 127.0.0.1:8600
    resolve_retries 30
    timeout retry 2s
    hold valid 5s
    accepted_payload_size 8192