Minimal ~/.m2/settings.xml

gistfile1.txt

<settings>
  <servers>
    <server>
      <id>apache.snapshots.https</id>
      <username><!-- your apache ldap username --></username>
      <password><!-- your apache ldap password --></password>
    </server>
    <server>
      <id>apache.releases.https</id>
      <username><!-- your apache ldap username --></username>
      <password><!-- your apache ldap password --></password>
    </server>
  </servers>
  <profiles>
    <profile>
      <id>apache-release</id>
      <properties>
        <gpg.keyname>....</gpg.keyname>
        <gpg.passphrase><!-- your passphrase for your gpg key goes here--></gpg.passphrase>
        <!-- or -->
        <gpg.useagent>true</gpg.useagent>
      </properties>
    </profile>
  </profiles>
</settings>