DOC: added setup example for multimaster in EE10

Author: Liudmila Mantrova

doc/src/sgml/multimaster.sgml

@@ -549,6 +549,87 @@ SELECT mtm.get_cluster_state();
       <para><emphasis role="strong">See Also</emphasis></para>
       <para><link linkend="multimaster-tuning-configuration-parameters">Tuning
       Configuration Parameters</link></para>
+    <sect4>
+      <title>Sample Cluster Configuration</title>
+    <para>
+      This section shows a sample configuration of a three-node cluster with
+      host names <literal>node1</literal>, <literal>node2</literal> and
+      <literal>node3</literal>. The name of the database
+      to be replicated is <literal>mydb</literal>.
+      The name of DBMS user with superuser rights to perform database
+      replication is <literal>myuser</literal>.
+    </para>
+  <orderedlist>
+   <listitem>
+    <para>
+      First, run the following commands on behalf of OS user
+      <literal>postgres</literal>, on all cluster nodes:
+    </para>
+      <programlisting>
+# Configure each node, and then create the myuser user
+# and mydb database owned by myuser.
+export PATH=/opt/pgpro/&edn;-&majorversion;/bin:$PATH
+export PGDATA=/var/lib/pgpro/&edn;-&majorversion;/data
+
+for i in `seq 1 3`; do
+echo "host replication myuser node$i md5" >> $PGDATA/pg_hba.conf
+echo "node$i:5432:mydb:myuser:myuserpassword" >> ~/.pgpass
+done
+chmod 0600 ~/.pgpass
+
+cat << EOF | psql --dbname=postgres --username=postgres --port=5432
+ALTER SYSTEM SET default_transaction_isolation = 'read committed';
+ALTER SYSTEM SET wal_level = logical;
+ALTER SYSTEM SET max_connections = 100;
+ALTER SYSTEM SET max_prepared_transactions = 300;
+ALTER SYSTEM SET max_wal_senders = 10;
+ALTER SYSTEM SET max_replication_slots = 10;
+ALTER SYSTEM SET max_worker_processes = 250;
+ALTER SYSTEM SET shared_preload_libraries = 'multimaster';
+CREATE USER myuser WITH SUPERUSER PASSWORD 'myuserpassword';
+CREATE DATABASE mydb OWNER myuser;
+EOF
+
+# Define the number of nodes in the cluster, assign node IDs,
+# and connection strings to the nodes. This example assumes
+# that node hostnames are node1, node2, and node3, and their
+# IDs are the corresponding numbers starting with 1.
+cat << EOF >> $PGDATA/postgresql.conf
+multimaster.max_nodes = 3
+multimaster.node_id = `hostname | awk '{ print substr($1,5,1) }'`
+multimaster.arbiter_port = 5433
+multimaster.conn_strings = 'dbname=mydb user=myuser host=node1 port=5432 arbiter_port=5433,dbname=mydb user=myuser host=node2 port=5432 arbiter_port=5433,dbname=mydb user=myuser host=node3 port=5432 arbiter_port=5433'
+EOF
+
+</programlisting>
+  </listitem>
+
+  <listitem>
+   <para>
+     On behalf of an OS user with superuser privileges, restart
+     <productname>&productname;</productname> service on all cluster nodes:
+   </para>
+<programlisting>
+sudo service postgrespro-&edn;-&majorversion; restart
+</programlisting>
+  </listitem>
+
+  <listitem>
+  <para>
+    Now create the <filename>multimaster</filename> extension on
+    one of the cluster nodes, on behalf of OS user <literal>postgres</literal>.
+    It will be replicated to all the other nodes automatically.
+    The following example illustrates extension creation on node1.
+<programlisting>
+psql --dbname=mydb --username=myuser --host=127.0.0.1 --port=5432 -c "CREATE EXTENSION IF NOT EXISTS multimaster"
+</programlisting>
+  </para>
+  <para>
+    The cluster is set up and ready to use.
+  </para>
+  </listitem>
+  </orderedlist>
+   </sect4>
   </sect3>
     <sect3 id="multimaster-tuning-configuration-parameters">
     <title>Tuning Configuration Parameters</title>