Configuring haproxy v23

TPA installs and configures haproxy on instances whose role contains haproxy.

By default, haproxy listens on 127.0.0.1:5432 for requests forwarded by pgbouncer running on the same instance. You must specify a list of haproxy_backend_servers to forward requests to.

TPA installs the latest available version of haproxy by default. Set haproxy_package_version: 1.9.15* or any valid version specifier to install a different version.

Note

See limitations of using wildcards in package_version in tpaexec-configure.

Haproxy packages are selected according to the type of architecture. You can use an EDB-managed haproxy package, but it requires a subscription. Packages from PGDG extras repo can be installed if required.

You can set the following variables on any haproxy instance.

Variable	Default value	Description
`haproxy_bind_address`	127.0.0.1	The address for haproxy to bind to.
`haproxy_port`	5432 (5444 for EPAS)	The TCP port for haproxy to listen on.
`haproxy_read_only_port`	5433 (5445 for EPAS)	TCP port for read-only load balancer.
`haproxy_backend_servers`	None	A list of Postgres instance names.
`haproxy_maxconn`	`max_connections`×0.9	The maximum number of connections allowed per backend server. The default is derived from the backend's `max_connections` setting.
`haproxy_peer_enabled`	True*	Add known haproxy hosts as `peer` list. *`False` if `failover_manager` is harp or patroni.

Read-only load balancer

Haproxy can be configured to listen on an additional port for read-only access to the database. Currently, this is supported only with the Patroni failover manager. The backend health check determines which Postgres instances are currently acting as replicas and uses round-robin load balancing to distribute traffic to them.

The read-only load balancer is disabled by default. You can turn it on by setting haproxy_read_only_load_balancer_enabled: true.

Server options

TPA generates /etc/haproxy/haproxy.cfg with a backend that has a default-server line and one line per backend server. All but the first one are marked as "backup" servers.

To add options to the default-server line, set haproxy_default_server_extra_options to a list of options on the haproxy instance.

To add options (which override the defaults) to the individual server lines for each backend, set haproxy_server_options to a list of options on the backend server.

Example

instances:
- Name: one
  vars:
    haproxy_server_options:
    - maxconn 33
- Name: two
…
- Name: proxy
  role:
  - haproxy
  vars:
    haproxy_backend_servers:
    - one
    - two
    haproxy_default_server_extra_options:
    - on-error mark-down
    - on-marked-down shutdown-sessions

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Configuring HARP

Configuring haproxy v23

Note

Read-only load balancer

Server options

Example

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