ha-guide/doc/ha-guide/source/controller-ha-haproxy.rst

HAProxy

HAProxy provides a fast and reliable HTTP reverse proxy and load balancer for TCP and HTTP-based applications. It is particularly suited for web sites crawling under very high loads while needing persistence or Layer 7 processing. Supporting tens of thousands of connections is clearly realistic with today’s hardware.

Each instance of HAProxy configures its front end to accept connections only from the virtual IP (VIP) address and to terminate them as a list of all instances of the corresponding service under load balancing. For example, any OpenStack API service.

This makes the instances of HAProxy act independently and fail over transparently together with the network endpoints (VIP addresses) failover and therefore shares the same SLA.

[TODO (Add note about using commercial load-balancers]

For detailed instructions about installing HAProxy on your nodes, see its official documentation. Note the following:

• HAProxy should not be a single point of failure; you need to ensure its availability by other means, such as Pacemaker or Keepalived.
• It is advisable to have multiple HAProxy instances running, where the number of these instances is a small odd number like 3 or 5.
• The common practice is to locate an HAProxy instance on each OpenStack controller in the environment.

Once configured (see example file below), add HAProxy to the cluster and ensure the VIP(s) can only run on machines where HAProxy is active:

pcs

$ pcs resource create lb-haproxy systemd:haproxy --clone
$ pcs constraint order start p_api-ip then lb-haproxy-clone kind=Optional
$ pcs constraint colocation add p_api-ip with lb-haproxy-clone

crmsh

TBA

Example Config File

Here is an example /etc/haproxy/haproxy.cfg configuration file. You need a copy of it on each controller node.

Note

To implement any changes made to this you must restart the HAProxy service

global
  chroot  /var/lib/haproxy
  daemon
  group  haproxy
  maxconn  4000
  pidfile  /var/run/haproxy.pid
  user  haproxy

defaults
  log  global
  maxconn  4000
  option  redispatch
  retries  3
  timeout  http-request 10s
  timeout  queue 1m
  timeout  connect 10s
  timeout  client 1m
  timeout  server 1m
  timeout  check 10s

listen dashboard_cluster
  bind <Virtual IP>:443
  balance  source
  option  tcpka
  option  httpchk
  option  tcplog
  server controller1 10.0.0.1:443 check inter 2000 rise 2 fall 5
  server controller2 10.0.0.2:443 check inter 2000 rise 2 fall 5
  server controller3 10.0.0.3:443 check inter 2000 rise 2 fall 5

listen galera_cluster
  bind <Virtual IP>:3306
  balance  source
  option  httpchk
  server controller1 10.0.0.4:3306 check port 9200 inter 2000 rise 2 fall 5
  server controller2 10.0.0.5:3306 backup check port 9200 inter 2000 rise 2 fall 5
  server controller3 10.0.0.6:3306 backup check port 9200 inter 2000 rise 2 fall 5

listen glance_api_cluster
  bind <Virtual IP>:9292
  balance  source
  option  tcpka
  option  httpchk
  option  tcplog
  server controller1 10.0.0.1:9292 check inter 2000 rise 2 fall 5
  server controller2 10.0.0.2:9292 check inter 2000 rise 2 fall 5
  server controller3 10.0.0.3:9292 check inter 2000 rise 2 fall 5

listen glance_registry_cluster
  bind <Virtual IP>:9191
  balance  source
  option  tcpka
  option  tcplog
  server controller1 10.0.0.1:9191 check inter 2000 rise 2 fall 5
  server controller2 10.0.0.2:9191 check inter 2000 rise 2 fall 5
  server controller3 10.0.0.3:9191 check inter 2000 rise 2 fall 5

listen keystone_admin_cluster
  bind <Virtual IP>:35357
  balance  source
  option  tcpka
  option  httpchk
  option  tcplog
  server controller1 10.0.0.1:35357 check inter 2000 rise 2 fall 5
  server controller2 10.0.0.2:35357 check inter 2000 rise 2 fall 5
  server controller3 10.0.0.3:35357 check inter 2000 rise 2 fall 5

listen keystone_public_internal_cluster
  bind <Virtual IP>:5000
  balance  source
  option  tcpka
  option  httpchk
  option  tcplog
  server controller1 10.0.0.1:5000 check inter 2000 rise 2 fall 5
  server controller2 10.0.0.2:5000 check inter 2000 rise 2 fall 5
  server controller3 10.0.0.3:5000 check inter 2000 rise 2 fall 5

listen nova_ec2_api_cluster
  bind <Virtual IP>:8773
  balance  source
  option  tcpka
  option  tcplog
  server controller1 10.0.0.1:8773 check inter 2000 rise 2 fall 5
  server controller2 10.0.0.2:8773 check inter 2000 rise 2 fall 5
  server controller3 10.0.0.3:8773 check inter 2000 rise 2 fall 5

listen nova_compute_api_cluster
  bind <Virtual IP>:8774
  balance  source
  option  tcpka
  option  httpchk
  option  tcplog
  server controller1 10.0.0.1:8774 check inter 2000 rise 2 fall 5
  server controller2 10.0.0.2:8774 check inter 2000 rise 2 fall 5
  server controller3 10.0.0.3:8774 check inter 2000 rise 2 fall 5

listen nova_metadata_api_cluster
  bind <Virtual IP>:8775
  balance  source
  option  tcpka
  option  tcplog
  server controller1 10.0.0.1:8775 check inter 2000 rise 2 fall 5
  server controller2 10.0.0.2:8775 check inter 2000 rise 2 fall 5
  server controller3 10.0.0.3:8775 check inter 2000 rise 2 fall 5

listen cinder_api_cluster
  bind <Virtual IP>:8776
  balance  source
  option  tcpka
  option  httpchk
  option  tcplog
  server controller1 10.0.0.1:8776 check inter 2000 rise 2 fall 5
  server controller2 10.0.0.2:8776 check inter 2000 rise 2 fall 5
  server controller3 10.0.0.3:8776 check inter 2000 rise 2 fall 5

listen ceilometer_api_cluster
  bind <Virtual IP>:8777
  balance  source
  option  tcpka
  option  tcplog
  server controller1 10.0.0.1:8777 check inter 2000 rise 2 fall 5
  server controller2 10.0.0.2:8777 check inter 2000 rise 2 fall 5
  server controller3 10.0.0.3:8777 check inter 2000 rise 2 fall 5

listen spice_cluster
  bind <Virtual IP>:6080
  balance  source
  option  tcpka
  option  tcplog
  server controller1 10.0.0.1:6080 check inter 2000 rise 2 fall 5
  server controller2 10.0.0.2:6080 check inter 2000 rise 2 fall 5
  server controller3 10.0.0.3:6080 check inter 2000 rise 2 fall 5

listen neutron_api_cluster
  bind <Virtual IP>:9696
  balance  source
  option  tcpka
  option  httpchk
  option  tcplog
  server controller1 10.0.0.1:9696 check inter 2000 rise 2 fall 5
  server controller2 10.0.0.2:9696 check inter 2000 rise 2 fall 5
  server controller3 10.0.0.3:9696 check inter 2000 rise 2 fall 5

listen swift_proxy_cluster
  bind <Virtual IP>:8080
  balance  source
  option  tcplog
  option  tcpka
  server controller1 10.0.0.1:8080 check inter 2000 rise 2 fall 5
  server controller2 10.0.0.2:8080 check inter 2000 rise 2 fall 5
  server controller3 10.0.0.3:8080 check inter 2000 rise 2 fall 5

Note the following:

• The Galera cluster configuration directive backup indicates that two of the three controllers are standby nodes. This ensures that only one node services write requests because OpenStack support for multi-node writes is not yet production-ready.
• The Telemetry API service configuration does not have the option httpchk directive as it cannot process this check properly. TODO: explain why the Telemetry API is so special
• [TODO: we need more commentary about the contents and format of this file]