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Chapter 19. Renaming IdM client systems
You can change the host name of an Identity Management (IdM) client system.
Renaming a client is a manual procedure. Do not perform it unless changing the host name is absolutely required.
Renaming an Identity Management client involves:
- Preparing the host. For details, see Preparing an IdM client for its renaming.
- Uninstalling the IdM client from the host. For details, see Uninstalling an Identity Management client.
- Renaming the host. For details, see Renaming the host system.
- Installing the IdM client on the host with the new name. For details, see Installing an Identity Management client in Installing Identity Management.
- Configuring the host after the IdM client installation. For details, see Re-adding services, re-generating certificates, and re-adding host groups.
19.1. Preparing an IdM client for its renaming
Before uninstalling the current client, make note of certain settings for the client. You will apply this configuration after re-enrolling the machine with a new host name.
Identify which services are running on the machine:
Use the
ipa service-find
command, and identify services with certificates in the output:ipa service-find old-client-name.example.com
$ ipa service-find old-client-name.example.com
Copy to Clipboard Copied! -
In addition, each host has a default host service which does not appear in the
ipa service-find
output. The service principal for the host service, also called a host principal, ishost/old-client-name.example.com
.
For all service principals displayed by
ipa service-find old-client-name.example.com
, determine the location of the corresponding keytabs on theold-client-name.example.com
system:find / -name "*.keytab"
# find / -name "*.keytab"
Copy to Clipboard Copied! Each service on the client system has a Kerberos principal in the form service_name/host_name@REALM, such as
ldap/old-client-name.example.com@EXAMPLE.COM
.Identify all host groups to which the machine belongs.
ipa hostgroup-find old-client-name.example.com
# ipa hostgroup-find old-client-name.example.com
Copy to Clipboard Copied!
19.2. Uninstalling an IdM client
Uninstalling a client removes the client from the Identity Management (IdM) domain, along with all of the specific IdM configuration of system services, such as System Security Services Daemon (SSSD). This restores the previous configuration of the client system.
Procedure
Enter the
ipa-client-install --uninstall
command:ipa-client-install --uninstall
[root@client ~]# ipa-client-install --uninstall
Copy to Clipboard Copied! Optional: Check that you cannot obtain a Kerberos ticket-granting ticket (TGT) for an IdM user:
kinit admin
[root@client ~]# kinit admin kinit: Client 'admin@EXAMPLE.COM' not found in Kerberos database while getting initial credentials [root@client ~]#
Copy to Clipboard Copied! If a Kerberos TGT ticket has been returned successfully, follow the additional uninstallation steps in Uninstalling an IdM client: additional steps after multiple past installations.
On the client, remove old Kerberos principals from each identified keytab other than
/etc/krb5.keytab
:ipa-rmkeytab -k /path/to/keytab -r EXAMPLE.COM
[root@client ~]# ipa-rmkeytab -k /path/to/keytab -r EXAMPLE.COM
Copy to Clipboard Copied! On an IdM server, remove all DNS entries for the client host from IdM:
ipa dnsrecord-del
[root@server ~]# ipa dnsrecord-del Record name: old-client-name Zone name: idm.example.com No option to delete specific record provided. Delete all? Yes/No (default No): true ------------------------ Deleted record "old-client-name"
Copy to Clipboard Copied! On the IdM server, remove the client host entry from the IdM LDAP server. This removes all services and revokes all certificates issued for that host:
ipa host-del client.idm.example.com
[root@server ~]# ipa host-del client.idm.example.com
Copy to Clipboard Copied! ImportantRemoving the client host entry from the IdM LDAP server is crucial if you think you might re-enroll the client in the future, with a different IP address or a different hostname.
19.3. Uninstalling an IdM client: additional steps after multiple past installations
If you install and uninstall a host as an Identity Management (IdM) client multiple times, the uninstallation procedure might not restore the pre-IdM Kerberos configuration.
In this situation, you must manually remove the IdM Kerberos configuration. In extreme cases, you must reinstall the operating system.
Prerequisites
-
You have used the
ipa-client-install --uninstall
command to uninstall the IdM client configuration from the host. However, you can still obtain a Kerberos ticket-granting ticket (TGT) for an IdM user from the IdM server. -
You have checked that the
/var/lib/ipa-client/sysrestore
directory is empty and hence you cannot restore the prior-to-IdM-client configuration of the system using the files in the directory.
Procedure
Check the
/etc/krb5.conf.ipa
file:If the contents of the
/etc/krb5.conf.ipa
file are the same as the contents of thekrb5.conf
file prior to the installation of the IdM client, you can:Remove the
/etc/krb5.conf
file:rm /etc/krb5.conf
# rm /etc/krb5.conf
Copy to Clipboard Copied! Rename the
/etc/krb5.conf.ipa
file into/etc/krb5.conf
:mv /etc/krb5.conf.ipa /etc/krb5.conf
# mv /etc/krb5.conf.ipa /etc/krb5.conf
Copy to Clipboard Copied!
-
If the contents of the
/etc/krb5.conf.ipa
file are not the same as the contents of thekrb5.conf
file prior to the installation of the IdM client, you can at least restore the Kerberos configuration to the state directly after the installation of the operating system:
Re-install the
krb5-libs
package:yum reinstall krb5-libs
# yum reinstall krb5-libs
Copy to Clipboard Copied! As a dependency, this command will also re-install the
krb5-workstation
package and the original version of the/etc/krb5.conf
file.
-
Remove the
var/log/ipaclient-install.log
file if present.
Verification
Try to obtain IdM user credentials. This should fail:
kinit admin
[root@r8server ~]# kinit admin kinit: Client 'admin@EXAMPLE.COM' not found in Kerberos database while getting initial credentials [root@r8server ~]#
Copy to Clipboard Copied!
The /etc/krb5.conf
file is now restored to its factory state. As a result, you cannot obtain a Kerberos TGT for an IdM user on the host.
19.4. Renaming the host system
Rename the machine as required. For example:
hostnamectl set-hostname new-client-name.example.com
# hostnamectl set-hostname new-client-name.example.com
You can now re-install the Identity Management (IdM) client to the IdM domain with the new host name.
19.5. Re-installing an IdM client
Install a client on your renamed host following the procedure described in Installing a client.
19.6. Re-adding services, re-generating certificates, and re-adding host groups
Procedure
On the Identity Management (IdM) server, add a new keytab for every service identified in the Preparing an IdM client for its renaming.
ipa service-add service_name/new-client-name
[root@server ~]# ipa service-add service_name/new-client-name
Copy to Clipboard Copied! Generate certificates for services that had a certificate assigned in the Preparing an IdM client for its renaming. You can do this:
- Using the IdM administration tools. See Managing Certificates for Users, Hosts, and Services.
-
Using the
certmonger
utility
- Re-add the client to the host groups identified in the Preparing an IdM client for its renaming.