title: Spring Security and multiple ldap configuration
body: <p>I use Spring Security to manage user and group securities.</p>
  
  <p>All datas are stored in a ldap server. My configuration is the following:</p>
  
  <pre><code>  &lt;authentication-manager alias="authenticationManager"&gt;
           &lt;ldap-authentication-provider 
             user-search-filter="(mail={0})"
             user-search-base=""
             group-search-filter="(uniqueMember={0})"
             group-search-base="ou=groups"
             group-role-attribute="cn"
             role-prefix="ROLE_"
             user-context-mapper-ref="contextMapper"&gt;
           &lt;/ldap-authentication-provider&gt;
           &lt;lda
    &lt;/authentication-manager&gt;
  
    &lt;beans:bean id="contextMapper" class="com.mycompany.CustomContextMapper"&gt;
      &lt;beans:property name="indexer" ref="entityIndexer" /&gt;
    &lt;/beans:bean&gt;
  
    &lt;ldap-user-service  server-ref="ldapServer" user-search-filter="(mail={0})" /&gt;
  
    &lt;ldap-server manager-dn="cn=admin,dc=springframework,dc=org" manager-password="password" url="ldap://server/dc=springframework,dc=org" id="ldapServer" /&gt;
  </code></pre>
  
  <p>All runs like a charm. Now, I want to add a second ldap server if the first one is down (fallback). I can't find an easy way to do it. </p>
  
  <p>So, my question si simple: how to add a second ldap server in this config to provide a fallback if the first one is down ?</p>