Ubuntu Manpage: ipa-client-install - Configure an IPA client

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Provided by: freeipa-client_4.3.1-0ubuntu1_amd64

NAME

       ipa-client-install - Configure an IPA client

SYNOPSIS

       ipa-client-install [OPTION]...

DESCRIPTION

Configures a client machine to use IPA for authentication and identity services.

By default this configures SSSD to connect to an IPA server for authentication and authorization.
Optionally one can instead configure PAM and NSS (Name Switching Service) to work with an IPA server over
Kerberos and LDAP.

An authorized user is required to join a client machine to IPA. This can take the form of a kerberos
principal or a one-time password associated with the machine.

This same tool is used to unconfigure IPA and attempts to return the machine to its previous state. Part
of this process is to unenroll the host from the IPA server. Unenrollment consists of disabling the
principal key on the IPA server so that it may be re-enrolled. The machine principal in /etc/krb5.keytab
(host/<fqdn>@REALM) is used to authenticate to the IPA server to unenroll itself. If this principal does
not exist then unenrollment will fail and an administrator will need to disable the host principal (ipa
host-disable <fqdn>).

Assumptions
The ipa-client-install script assumes that the machine has already generated SSH keys. It will not
generate SSH keys of its own accord. If SSH keys are not present (e.g when running the ipa-client-install
in a kickstart, before ever running sshd), they will not be uploaded to the client host entry on the
server.

Hostname Requirements
Client must use a static hostname. If the machine hostname changes for example due to a dynamic hostname
assignment by a DHCP server, client enrollment to IPA server breaks and user then would not be able to
perform Kerberos authentication.

--hostname option may be used to specify a static hostname that persists over reboot.

DNS Autodiscovery
Client installer by default tries to search for _ldap._tcp.DOMAIN DNS SRV records for all domains that
are parent to its hostname. For example, if a client machine has a hostname 'client1.lab.example.com',
the installer will try to retrieve an IPA server hostname from _ldap._tcp.lab.example.com,
_ldap._tcp.example.com and _ldap._tcp.com DNS SRV records, respectively. The discovered domain is then
used to configure client components (e.g. SSSD and Kerberos 5 configuration) on the machine.

When the client machine hostname is not in a subdomain of an IPA server, its domain can be passed with
--domain option. In that case, both SSSD and Kerberos components have the domain set in the configuration
files and will use it to autodiscover IPA servers.

Client machine can also be configured without a DNS autodiscovery at all. When both --server and --domain
options are used, client installer will use the specified server and domain directly. --server option
accepts multiple server hostnames which can be used for failover mechanism. Without DNS autodiscovery,
Kerberos is configured with a fixed list of KDC and Admin servers. SSSD is still configured to either
try to read domain's SRV records or the specified fixed list of servers. When --fixed-primary option is
specified, SSSD will not try to read DNS SRV record at all (see sssd-ipa(5) for details).

The Failover Mechanism
When some of the IPA servers is not available, client components are able to fallback to other IPA
replica and thus preserving a continued service. When client machine is configured to use DNS SRV record
autodiscovery (no fixed server was passed to the installer), client components do the fallback
automatically, based on the IPA server hostnames and priorities discovered from the DNS SRV records.

If DNS autodiscovery is not available, clients should be configured at least with a fixed list of IPA
servers that can be used in case of a failure. When only one IPA server is configured, IPA client
services will not be available in case of a failure of the IPA server. Please note, that in case of a
fixed list of IPA servers, the fixed server lists in client components need to be updated when a new IPA
server is enrolled or a current IPA server is decommissioned.

Coexistence With Other Directory Servers
Other directory servers deployed in the network (e.g. Microsoft Active Directory) may use the same DNS
SRV records to denote hosts with a directory service (_ldap._tcp.DOMAIN). Such DNS SRV records may break
the installation if the installer discovers these DNS records before it finds DNS SRV records pointing to
IPA servers. The installer would then fail to discover the IPA server and exit with error.

In order to avoid the aforementioned DNS autodiscovery issues, the client machine hostname should be in a
domain with properly defined DNS SRV records pointing to IPA servers, either manually with a custom DNS
server or with IPA DNS integrated solution. A second approach would be to avoid autodiscovery and
configure the installer to use a fixed list of IPA server hostnames using the --server option and with a
--fixed-primary option disabling DNS SRV record autodiscovery in SSSD.

Re-enrollment of the host
Requirements:

1. Host has not been un-enrolled (the ipa-client-install --uninstall command has not been run).
2. The host entry has not been disabled via the ipa host-disable command.

If this has been the case, host can be re-enrolled using the usual methods.

There are two method of authenticating a re-enrollment:

1. You can use --force-join option with ipa-client-install command. This authenticates the re-enrollment
using the admin's credentials provided via the -w/--password option.
2. If providing the admin's password via the command line is not an option (e.g you want to create a
script to re-enroll a host and keep the admin's password secure), you can use backed up keytab from the
previous enrollment of this host to authenticate. See --keytab option.

Consequences of the re-enrollment on the host entry:

1. A new host certificate is issued
2. The old host certificate is revoked
3. New SSH keys are generated
4. ipaUniqueID is preserved

OPTIONS

BASIC OPTIONS
--domain=DOMAIN
Set the domain name to DOMAIN. When no --server option is specified, the installer will try to
discover all available servers via DNS SRV record autodiscovery (see DNS Autodiscovery section for
details).

--server=SERVER
Set the IPA server to connect to. May be specified multiple times to add multiple servers to
ipa_server value in sssd.conf or krb5.conf. Only the first value is considered when used with
--no-sssd. When this option is used, DNS autodiscovery for Kerberos is disabled and a fixed list
of KDC and Admin servers is configured.

--realm=REALM_NAME
Set the IPA realm name to REALM_NAME. Under normal circumstances, this option is not needed as the
realm name is retrieved from the IPA server.

--fixed-primary
Configure SSSD to use a fixed server as the primary IPA server. The default is to use DNS SRV
records to determine the primary server to use and fall back to the server the client is enrolled
with. When used in conjunction with --server then no _srv_ value is set in the ipa_server option
in sssd.conf.

-p, --principal
Authorized kerberos principal to use to join the IPA realm.

-w PASSWORD, --password=PASSWORD
Password for joining a machine to the IPA realm. Assumes bulk password unless principal is also
set.

-W Prompt for the password for joining a machine to the IPA realm.

-k, --keytab
Path to backed up host keytab from previous enrollment. Joins the host even if it is already
enrolled.

--mkhomedir
Configure PAM to create a users home directory if it does not exist.

--hostname
The hostname of this machine (FQDN). If specified, the hostname will be set and the system
configuration will be updated to persist over reboot. By default a nodename result from uname(2)
is used.

--force-join
Join the host even if it is already enrolled.

--ntp-server=NTP_SERVER
Configure ntpd to use this NTP server. This option can be used multiple times.

-N, --no-ntp
Do not configure or enable NTP.

--force-ntpd
Stop and disable any time&date synchronization services besides ntpd.

--nisdomain=NIS_DOMAIN
Set the NIS domain name as specified. By default, this is set to the IPA domain name.

--no-nisdomain
Do not configure NIS domain name.

--ssh-trust-dns
Configure OpenSSH client to trust DNS SSHFP records.

--no-ssh
Do not configure OpenSSH client.

--no-sshd
Do not configure OpenSSH server.

--no-sudo
Do not configure SSSD as a data source for sudo.

--no-dns-sshfp
Do not automatically create DNS SSHFP records.

--noac Do not use Authconfig to modify the nsswitch.conf and PAM configuration.

-f, --force
Force the settings even if errors occur

--kinit-attempts=KINIT_ATTEMPTS
In case of unresponsive KDC (e.g. when enrolling multiple hosts at once in a heavy load
environment) repeat the request for host Kerberos ticket up to a total number of KINIT_ATTEMPTS
times before giving up and aborting client installation. Default number of attempts is 5. The
request is not repeated when there is a problem with host credentials themselves (e.g. wrong
keytab format or invalid principal) so using this option will not lead to account lockouts.

-d, --debug
Print debugging information to stdout

-U, --unattended
Unattended installation. The user will not be prompted.

--ca-cert-file=CA_FILE
Do not attempt to acquire the IPA CA certificate via automated means, instead use the CA
certificate found locally in in CA_FILE. The CA_FILE must be an absolute path to a PEM formatted
certificate file. The CA certificate found in CA_FILE is considered authoritative and will be
installed without checking to see if it's valid for the IPA domain.

--request-cert
Request certificate for the machine. The certificate will be stored in /etc/ipa/nssdb under the
nickname "Local IPA host".

--automount-location=LOCATION
Configure automount by running ipa-client-automount(1) with LOCATION as automount location.

--configure-firefox
Configure Firefox to use IPA domain credentials.

--firefox-dir=DIR
Specify Firefox installation directory. For example: '/usr/lib/firefox'

--ip-address=IP_ADDRESS
Use IP_ADDRESS in DNS A/AAAA record for this host. May be specified multiple times to add multiple
DNS records.

--all-ip-addresses
Create DNS A/AAAA record for each IP address on this host.

SSSD OPTIONS
--permit
Configure SSSD to permit all access. Otherwise the machine will be controlled by the Host-based
Access Controls (HBAC) on the IPA server.

--enable-dns-updates
This option tells SSSD to automatically update DNS with the IP address of this client.

--no-krb5-offline-passwords
Configure SSSD not to store user password when the server is offline.

-S, --no-sssd
Do not configure the client to use SSSD for authentication, use nss_ldap instead.

--preserve-sssd
Disabled by default. When enabled, preserves old SSSD configuration if it is not possible to merge
it with a new one. Effectively, if the merge is not possible due to SSSDConfig reader encountering
unsupported options, ipa-client-install will not run further and ask to fix SSSD config first.
When this option is not specified, ipa-client-install will back up SSSD config and create new one.
The back up version will be restored during uninstall.

UNINSTALL OPTIONS
--uninstall
Remove the IPA client software and restore the configuration to the pre-IPA state.

-U, --unattended
Unattended uninstallation. The user will not be prompted.

FILES

       Files that will be replaced if SSSD is configured (default):

              /etc/sssd/sssd.conf

       Files that will be replaced if they exist and SSSD is not configured (--no-sssd):

              /etc/ldap.conf
              /etc/nss_ldap.conf
              /etc/libnss-ldap.conf
              /etc/pam_ldap.conf
              /etc/nslcd.conf

       Files replaced if NTP is enabled:

              /etc/ntp.conf
              /etc/sysconfig/ntpd
              /etc/ntp/step-tickers

       Files always created (replacing existing content):

              /etc/krb5.conf
              /etc/ipa/ca.crt
              /etc/ipa/default.conf
              /etc/ipa/nssdb
              /etc/openldap/ldap.conf

       Files updated, existing content is maintained:

              /etc/nsswitch.conf
              /etc/krb5.keytab
              /etc/sysconfig/network

EXIT STATUS

       0 if the installation was successful

       1 if an error occurred

       2 if uninstalling and the client is not configured

       3 if installing and the client is already configured

       4 if an uninstall error occurred