puppet: wal-g backups are required for replication.

Previously, it was possible to configure `wal-g` backups without
replication enabled; this resulted in only daily backups, not
streaming backups.  It was also possible to enable replication without
configuring the `wal-g` backups bucket; this simply failed to work.

Make `wal-g` backups always streaming, and warn loudly if replication
is enabled but `wal-g` is not configured.

docs/production/deployment.md

@@ -508,23 +508,15 @@ things you need to be careful about when configuring it:
 Zulip's configuration allows for [warm standby database
 replicas][warm-standby] as a disaster recovery solution; see the
 linked PostgreSQL documentation for details on this type of
-deployment. Zulip's configuration leverages `wal-g`, our [database
-backup solution][wal-g], and thus requires that it be configured for
-the primary and all secondary warm standby replicas.
+deployment. Zulip's configuration builds on top of `wal-g`, our
+[database backup solution][wal-g], and thus requires that it be
+configured for the primary and all secondary warm standby replicas.
 
-The primary should have log-shipping enabled, with:
+Warm spare replicas should also have `wal-g` backups configured, and
+their primary replica and replication username set:
 
 ```ini
 [postgresql]
-replication = yes
-```
-
-Warm spare replicas should have log-shipping enabled, and their
-primary replica and replication username configured:
-
-```ini
-[postgresql]
-replication = yes
 replication_user = replicator
 replication_primary = hostname-of-primary.example.com
 ```
@@ -688,14 +680,6 @@ setting](https://www.postgresql.org/docs/current/runtime-config-connection.html#
 Override PostgreSQL's [`random_page_cost`
 setting](https://www.postgresql.org/docs/current/runtime-config-query.html#GUC-RANDOM-PAGE-COST)
 
-#### `replication`
-
-Set to true to enable replication to enable [log shipping replication
-between PostgreSQL servers](#postgresql-warm-standby). This should be
-enabled on the primary, as well as any replicas, and further requires
-configuration of
-[wal-g](export-and-import.md#backup-details).
-
 #### `replication_primary`
 
 On the [warm standby replicas](#postgresql-warm-standby), set to the

puppet/zulip/manifests/profile/postgresql.pp

@@ -13,7 +13,7 @@ class zulip::profile::postgresql {
 
   $listen_addresses = zulipconf('postgresql', 'listen_addresses', undef)
 
-  $replication = zulipconf('postgresql', 'replication', undef)
+  $s3_backups_bucket = zulipsecret('secrets', 's3_backups_bucket', '')
   $replication_primary = zulipconf('postgresql', 'replication_primary', undef)
   $replication_user = zulipconf('postgresql', 'replication_user', undef)
 
@@ -38,6 +38,13 @@ class zulip::profile::postgresql {
   }
 
   if $replication_primary != '' and $replication_user != '' {
+    if $s3_backups_bucket == '' {
+      $message = @(EOT/L)
+          Replication is enabled, but s3_backups_bucket is not set in zulip-secrets.conf!  \
+          Streaming replication requires wal-g backups be configured.
+          |-EOT
+      warning($message)
+    }
     if $zulip::postgresql_common::version in ['10', '11'] {
       # PostgreSQL 11 and below used a recovery.conf file for replication
       file { "${zulip::postgresql_base::postgresql_confdir}/recovery.conf":

puppet/zulip/templates/postgresql/12/postgresql.conf.template.erb

@@ -787,8 +787,8 @@ effective_io_concurrency = <%= @effective_io_concurrency %>
 listen_addresses = <%= @listen_addresses %>
 <% end -%>
 
-<% if @replication != '' || (@replication_primary != '' && @replication_user != '') -%>
-# Replication
+<% if @s3_backups_bucket != '' -%>
+# Streaming backups and replication
 max_wal_senders = 5
 archive_mode = on
 archive_command = '/usr/bin/timeout 10m /usr/local/bin/env-wal-g wal-push %p'

puppet/zulip/templates/postgresql/13/postgresql.conf.template.erb

@@ -818,8 +818,8 @@ effective_io_concurrency = <%= @effective_io_concurrency %>
 listen_addresses = <%= @listen_addresses %>
 <% end -%>
 
-<% if @replication != '' || (@replication_primary != '' && @replication_user != '') -%>
-# Replication
+<% if @s3_backups_bucket != '' -%>
+# Streaming backups and replication
 max_wal_senders = 5
 archive_mode = on
 archive_command = '/usr/bin/timeout 10m /usr/local/bin/env-wal-g wal-push %p'

puppet/zulip/templates/postgresql/14/postgresql.conf.template.erb

@@ -839,8 +839,8 @@ effective_io_concurrency = <%= @effective_io_concurrency %>
 listen_addresses = <%= @listen_addresses %>
 <% end -%>
 
-<% if @replication != '' || (@replication_primary != '' && @replication_user != '') -%>
-# Replication
+<% if @s3_backups_bucket != '' -%>
+# Streaming backups and replication
 max_wal_senders = 5
 archive_mode = on
 archive_command = '/usr/bin/timeout 10m /usr/local/bin/env-wal-g wal-push %p'