6.5. Managing Server Roles

Based on the services installed on an IdM server, it can perform various server roles. For example: CA server, DNS server, or key recovery authority (KRA) server.

6.5.1. Viewing Server Roles

Web UI: Viewing Server Roles

For a complete list of the supported server roles, see IPA Server → Topology → Server Roles.
  • Role status absent means that no server in the topology is performing the role.
  • Role status enabled means that one or more servers in the topology are performing the role.
Server Roles in the Web UI

Figure 6.14. Server Roles in the Web UI

Command Line: Viewing Server Roles

The ipa config-show command displays all CA servers, NTP servers, and the current CA renewal master: 
$ ipa config-show
  ...
  IPA masters: server1.example.com, server2.example.com, server3.example.com
  IPA CA servers: server1.example.com, server2.example.com
  IPA NTP servers: server1.example.com, server2.example.com, server3.example.com
  IPA CA renewal master: server1.example.com
The ipa server-show command displays a list of roles enabled on a particular server. For example, for a list of roles enabled on server.example.com: 
$ ipa server-show
Server name: server.example.com
  ...
  Enabled server roles: CA server, DNS server, NTP server, KRA server
The ipa server-find --servrole searches for all servers with a particular server role enabled. For example, to search for all CA servers: 
$ ipa server-find --servrole "CA server"
---------------------
2 IPA servers matched
---------------------
  Server name: server1.example.com
  ...

  Server name: server2.example.com
  ...
----------------------------
Number of entries returned 2
----------------------------

6.5.2. Promoting a Replica to a Master CA Server

Note

This section describes changing the CA renewal master at domain level 1 (see Chapter 7, Displaying and Raising the Domain Level). For documentation on changing the CA renewal master at domain level 0, see Section D.4, “Promoting a Replica to a Master CA Server”.
In a topology that includes multiple replicas, one of them acts as the master CA server: it manages the renewal of CA subsystem certificates and generates certificate revocation lists (CRLs). By default, the master CA is the initial server from which replicas were created.
If you plan to take the master CA server offline or decommission it, promote another CA server to take the its place as the new CA renewal master:
  1. Configure the replica to handle CA subsystem certificate renewal.
  2. Configure the replica to generate CRLs. See Section 6.5.2.2, “Changing Which Server Generates CRLs”.
  3. Before decommissioning the previous master CA server, make sure the new master works properly. See Section 6.5.2.3, “Verifying That the New Master CA Server Is Configured Correctly”.

6.5.2.1. Changing the Current CA Renewal Master

Web UI: Changing the Current CA Renewal Master

  1. Select IPA Server → Configuration.
  2. In the IPA CA renewal master field, select the new CA renewal master.

Command Line: Changing the Current CA Renewal Master

Use the ipa config-mod --ca-renewal-master-server command: 
$ ipa config-mod --ca-renewal-master-server new_ca_renewal_master.example.com
  ...
  IPA masters: old_ca_renewal_master.example.com, new_ca_renewal_master.example.com
  IPA CA servers: old_ca_renewal_master.example.com, new_ca_renewal_master.example.com
  IPA NTP servers: old_ca_renewal_master.example.com, new_ca_renewal_master.example.com
  IPA CA renewal master: new_ca_renewal_master.example.com
The output confirms that the update was successful.

6.5.2.2. Changing Which Server Generates CRLs

To change which server generates CRLs, stop CRL generation on the current CRL generation master, and then enable it on the other server.

Identifying the Current CRL Generation Master

Examine the /etc/pki/pki-tomcat/ca/CS.cfg file on each server with a CA installed:
  • On the CRL generation master, the ca.crl.MasterCRL.enableCRLUpdates parameter is set to true: 
    # grep ca.crl.MasterCRL.enableCRLUpdates /etc/pki/pki-tomcat/ca/CS.cfg
ca.crl.MasterCRL.enableCRLUpdates=true
  • On CRL generation clones, the parameter is set to false.

Stopping CRL Generation on the Current CRL Generation Master

  1. Stop the CA service: 
    # systemctl stop pki-tomcatd@pki-tomcat.service
  2. Disable CRL generation on the server. Open the /etc/pki/pki-tomcat/ca/CS.cfg file, and set the values of the ca.crl.MasterCRL.enableCRLCache and ca.crl.MasterCRL.enableCRLUpdates parameters to false: 
    ca.crl.MasterCRL.enableCRLCache=false
ca.crl.MasterCRL.enableCRLUpdates=false
  3. Start the CA service: 
    # systemctl start pki-tomcatd@pki-tomcat.service
  4. Configure Apache to redirect CRL requests to the new master. Open the /etc/httpd/conf.d/ipa-pki-proxy.conf file, and uncomment the RewriteRule argument: 
    # Only enable this on servers that are not generating a CRL
RewriteRule ^/ipa/crl/MasterCRL.bin https://server.example.com/ca/ee/ca/getCRL?op=getCRL&crlIssuingPoint=MasterCRL [L,R=301,NC]
  5. Restart Apache: 
    # systemctl restart httpd.service
Before, this server responded to CRL requests. Now, all CRL requests are routed to the previous CA master.

Configure a Server to Generate CRLs

  1. Stop the CA service: 
    # systemctl stop pki-tomcatd@pki-tomcat.service
  2. Enable CRL generation on the server. Set the values of the ca.crl.MasterCRL.enableCRLCache and ca.crl.MasterCRL.enableCRLUpdates parameters to true: 
    ca.crl.MasterCRL.enableCRLCache=true
ca.crl.MasterCRL.enableCRLUpdates=true
  3. Start the CA service: 
    # systemctl start pki-tomcatd@pki-tomcat.service
  4. Configure Apache to disable redirecting CRL requests. Open the /etc/httpd/conf.d/ipa-pki-proxy.conf file, and comment out the RewriteRule argument: 
    #RewriteRule ^/ipa/crl/MasterCRL.bin https://server.example.com/ca/ee/ca/getCRL?op=getCRL&crlIssuingPoint=MasterCRL [L,R=301,NC]
    Before, all CRL requests were routed to the previous CA master. Now, this server will respond to CRL requests.
  5. Restart Apache: 
    # systemctl restart httpd.service

6.5.2.3. Verifying That the New Master CA Server Is Configured Correctly

Make sure the /var/lib/ipa/pki-ca/publish/MasterCRL.bin file exists on the new master CA server.
The file is generated based on the time interval defined in the /etc/pki/pki-tomcat/ca/CS.cfg file using the ca.crl.MasterCRL.autoUpdateInterval parameter. The default value is 240 minutes (4 hours).

Note

If you update the ca.crl.MasterCRL.autoUpdateInterval parameter, the change will become effective after the next already scheduled CRL update.
If the file exists, the new master CA server is configured correctly, and you can safely dismiss the previous CA master system.

6.5.3. Demotion and Promotion of Hidden Replicas

After a replica has been installed, you can change whether the replica is hidden or visible:
  • To demote a visible replica to a hidden replica:
    1. If the replica is a CA renewal master, move the service to another replica. For details, see Section 6.5.2.1, “Changing the Current CA Renewal Master”.
    2. Change the state of the replica to hidden: 
      # ipa server-state replica.idm.example.com --state=hidden
  • To promote a hidden replica to a visible replica, enter: 
    # ipa server-state replica.idm.example.com --state=enabled

Note

The hidden replica feature is available in Red Hat Enterprise Linux 7.7 and later as a Technology Preview and, therefore, not supported.