repmgr/doc/configuration-password-management.xml

<sect1 id="configuration-password-management" xreflabel="password management">

  <title>Password Management</title>
  <indexterm>
    <primary>passwords</primary>
  </indexterm>

  <sect2 id="configuration-password-management-options" xreflabel="password management options">
  <title>Password Management Options</title>
  <indexterm>
    <primary>passwords</primary>
    <secondary>options for managing</secondary>
  </indexterm>

  <para>
    For security purposes it's desirable to protect database access using a password.
  </para>
  <para>
    PostgreSQL has three ways of providing a password:
    <itemizedlist spacing="compact" mark="bullet">

       <listitem>
         <simpara>
           including the password in the <option>conninfo</option> string
           (e.g. &quot;<literal>host=node1 dbname=repmgr user=repmgr password=foo</literal>&quot;)
         </simpara>
       </listitem>

       <listitem>
         <simpara>
           exporting the password as an environment variable (<envar>PGPASSWORD</envar>)
         </simpara>
       </listitem>

       <listitem>
         <simpara>
           storing the password in a dedicated password file
         </simpara>
       </listitem>
    </itemizedlist>
  </para>
  <para>
    We strongly advise against including the password in the <option>conninfo</option> string, as
    this will result in the database password being exposed in various places, including in the
    <filename>repmgr.conf</filename> file, the <literal>repmgr.nodes</literal> table, any output
    generated by &repmgr; which lists the node <option>conninfo</option> strings (e.g.
    <link linkend="repmgr-cluster-show">repmgr cluster show</link>) and in the &repmgr; log file,
    particularly at <option>log_level=DEBUG</option>.
  </para>
  <note>
    <para>
      Currently &repmgr; does not fully support use of the <option>password</option> option in the
      <option>conninfo</option> string.
    </para>
  </note>
  <para>
    Exporting the password as an environment variable (<envar>PGPASSWORD</envar>) is considered
    less insecure, but the PostgreSQL documentation explicitly recommends against doing this:
   <blockquote>
     <attribution><ulink url="https://www.postgresql.org/docs/current/libpq-envars.html">Environment Variables</ulink></attribution>
     <para>
       <envar>PGPASSWORD</envar> behaves the same as the <option>password</option>
       connection parameter. Use of this environment variable
       is not recommended for security reasons, as some operating systems
       allow non-root users to see process environment variables via
       <application>ps</application>; instead consider using a password file.
     </para>
    </blockquote>

  </para>
  <para>
    The most secure option for managing passwords is to use a dedicated password file; see the following
    section for more details.
  </para>

  </sect2>

  <sect2 id="configuration-password-file" xreflabel="password file">
    <title>Using a password file</title>
    <indexterm>
      <primary>pgpass</primary>
    </indexterm>

    <indexterm>
      <primary>.pgpass</primary>
    </indexterm>

    <indexterm>
      <primary>passwords</primary>
      <secondary>using a password file</secondary>
    </indexterm>

    <para>
      The most secure way of storing passwords is in a password file,
      which by default is <filename>~/.pgpass</filename>. This file
      can only be read by the system user who owns the file, and
      PostgreSQL will refuse to use the file unless read/write
      permissions are restricted to the file owner. The password(s)
      contained in the file will not be directly accessed by
      &repmgr; (or any other libpq-based client software such as <application>psql</application>).
    </para>
    <para>
       For full details see the
       <ulink url="https://www.postgresql.org/docs/current/libpq-pgpass.html">PostgreSQL password file documentation</ulink>.
    </para>
    <para>
      For use with &repmgr;, the <filename>~/.pgpass</filename> must two entries for each
      node in the replication cluster: one for the &repmgr; user who accesses the &repmgr; metadatabase,
      and one for replication connections (regardless of whether a dedicated replication user is used).
      The file must be present on each node in the replication cluster.
    </para>
    <para>
      A <filename>~/.pgpass</filename> file for a 3-node cluster where the <literal>repmgr</literal> database user
      is used for both for accessing the  &repmgr; metadatabase and for replication connections would look like this:
      <programlisting>
node1:5432:repmgr:repmgr:foo
node1:5432:replication:repmgr:foo
node2:5432:repmgr:repmgr:foo
node2:5432:replication:repmgr:foo
node3:5432:repmgr:repmgr:foo
node3:5432:replication:repmgr:foo</programlisting>
      If a dedicated replication user (here: <literal>repluser</literal>) is in use, the file would look like this:
      <programlisting>
node1:5432:repmgr:repmgr:foo
node1:5432:replication:repluser:foo
node2:5432:repmgr:repmgr:foo
node2:5432:replication:repluser:foo
node3:5432:repmgr:repmgr:foo
node3:5432:replication:repluser:foo</programlisting>
      If you are planning to use the <option>-S</option>/<option>--superuser</option> option,
      there must also be an entry enabling the superuser to connect to the &repmgr; database.
      Assuming the superuser is <literal>postgres</literal>, the file would look like this:
        <programlisting>
node1:5432:repmgr:repmgr:foo
node1:5432:repmgr:postgres:foo
node1:5432:replication:repluser:foo
node2:5432:repmgr:repmgr:foo
node2:5432:repmgr:postgres:foo
node2:5432:replication:repluser:foo
node3:5432:repmgr:repmgr:foo
node3:5432:repmgr:postgres:foo
node3:5432:replication:repluser:foo</programlisting>
    </para>

    <para>
      The <filename>~/.pgpass</filename> file can be simplified with the use of wildcards if
      there is no requirement to restrict provision of passwords to particular hosts, ports
      or databases. The preceding file could then be formatted like this:
        <programlisting>
*:*:*:repmgr:foo
*:*:*:postgres:foo
</programlisting>
    </para>

    <note>
      <para>
        It's possible to specify an alternative location for the <filename>~/.pgpass</filename> file, either via
        the environment variable <envar>PGPASSFILE</envar>, or (from PostgreSQL 9.6) using the
        <varname>passfile</varname> parameter in connection strings.
      </para>
      <para>
        If using the <varname>passfile</varname> parameter, it's essential to ensure the file is in the same
        location on all nodes, as when connecting to a remote node, the file referenced is the one on the
        local node.
      </para>
      <para>
        Additionally, you <emphasis>must</emphasis> specify the passfile location in <filename>repmgr.conf</filename>
        with the <option>passfile</option> option so &repmgr; can write the correct path when creating the
        <option>primary_conninfo</option> parameter for replication configuration on standbys.
      </para>
    </note>

  </sect2>

</sect1>