Chapter 5. Recovering from data loss with IdM backups

You can use the ipa-restore utility to restore an IdM server to a previous state captured in an IdM backup.

5.1. When to restore from an IdM backup

You can respond to several disaster scenarios by restoring from an IdM backup:

  • Undesirable changes were made to the LDAP content: Entries were modified or deleted, replication carried out those changes throughout the deployment, and you want to revert those changes. Restoring a data-only backup returns the LDAP entries to the previous state without affecting the IdM configuration itself.
  • Total Infrastructure Loss, or loss of all CA instances: If a disaster damages all Certificate Authority replicas, the deployment has lost the ability to rebuild itself by deploying additional servers. In this situation, restore a backup of a CA Replica and build new replicas from it.

  • An upgrade on an isolated server failed: The operating system remains functional, but the IdM data is corrupted, which is why you want to restore the IdM system to a known good state. Red Hat recommends working with Technical Support to diagnose and troubleshoot the issue. If those efforts fail, restore from a full-server backup.

    Important

    The preferred solution for hardware or upgrade failure is to rebuild the lost server from a replica. For more information, see Recovering a single server with replication.

5.2. Considerations when restoring from an IdM backup

If you have a backup created with the ipa-backup utility, you can restore your IdM server or the LDAP content to the state they were in when the backup was performed.

The following are the key considerations while restoring from an IdM backup:

  • You can only restore a backup on a server that matches the configuration of the server where the backup was originally created. The server must have:

    • The same hostname
    • The same IP address
    • The same version of IdM software
  • If one IdM server among many is restored, the restored server becomes the only source of information for IdM. All other servers must be re-initialized from the restored server.
  • Since any data created after the last backup will be lost, do not use the backup and restore solution for normal system maintenance.
  • If a server is lost, Red Hat recommends rebuilding the server by reinstalling it as a replica, instead of restoring from a backup. Creating a new replica preserves data from the current working environment. For more information, see Preparing for server loss with replication.
  • The backup and restore features can only be managed from the command line and are not available in the IdM web UI.
  • You cannot restore from backup files located in the /tmp or /var/tmp directories. The IdM Directory Server uses a PrivateTmp directory and cannot access the /tmp or /var/tmp directories commonly available to the operating system.
Tip

Restoring from a backup requires the same software (RPM) versions on the target host as were installed when the backup was performed. Due to this, Red Hat recommends restoring from a Virtual Machine snapshot rather than a backup. For more information, see Recovering from data loss with VM snapshots.

5.3. Restoring an IdM server from a backup

The following procedure describes restoring an IdM server, or its LDAP data, from an IdM backup.

Figure 5.1. Replication Topology used in this example

Diagram showing 3 IdM servers: host server1.example.com needs to be restored from backup. Host caReplica2.example.com is a Certificate Authority replica that is connected to server1.example.com. Host replica3.example.com is a regular server that is connected to caReplica2.example.com

Table 5.1. Server naming conventions used in this example

Server host nameFunction

server1.example.com

The server that needs to be restored from backup.

caReplica2.example.com

A Certificate Authority (CA) replica connected to the server1.example.com host.

replica3.example.com

A replica connected to the caReplica2.example.com host.

Prerequisites

  • You have generated a full-server or data-only backup of the IdM server with the ipa-backup utility. See Creating a backup.
  • Your backup files are not in the /tmp or /var/tmp directories.
  • Before performing a full-server restore from a full-server backup, uninstall IdM from the server and reinstall IdM using the same server configuration as before.

Procedure

  1. Use the ipa-restore utility to restore a full-server or data-only backup.

    • If the backup directory is in the default /var/lib/ipa/backup/ location, enter only the name of the directory: 

      [root@server1 ~]# ipa-restore ipa-full-2020-01-14-12-02-32

    • If the backup directory is not in the default location, enter its full path: 

      [root@server1 ~]# ipa-restore /mybackups/ipa-data-2020-02-01-05-30-00
      Note

      The ipa-restore utility automatically detects the type of backup that the directory contains, and performs the same type of restore by default. To perform a data-only restore from a full-server backup, add the --data option to the ipa-restore command: 

      [root@server1 ~]# ipa-restore --data ipa-full-2020-01-14-12-02-32

  2. Enter the Directory Manager password. 

    Directory Manager (existing master) password:

  3. Enter yes to confirm overwriting current data with the backup. 

    Preparing restore from /var/lib/ipa/backup/ipa-full-2020-01-14-12-02-32 on server1.example.com
Performing FULL restore from FULL backup
Temporary setting umask to 022
Restoring data will overwrite existing live data. Continue to restore? [no]: yes

  4. The ipa-restore utility disables replication on all servers that are available: 

    Each master will individually need to be re-initialized or
re-created from this one. The replication agreements on
masters running IPA 3.1 or earlier will need to be manually
re-enabled. See the man page for details.
Disabling all replication.
Disabling replication agreement on server1.example.com to caReplica2.example.com
Disabling CA replication agreement on server1.example.com to caReplica2.example.com
Disabling replication agreement on caReplica2.example.com to server1.example.com
Disabling replication agreement on caReplica2.example.com to replica3.example.com
Disabling CA replication agreement on caReplica2.example.com to server1.example.com
Disabling replication agreement on replica3.example.com to caReplica2.example.com

    The utility then stops IdM services, restores the backup, and restarts the services: 

    Stopping IPA services
Systemwide CA database updated.
Restoring files
Systemwide CA database updated.
Restoring from userRoot in EXAMPLE-COM
Restoring from ipaca in EXAMPLE-COM
Restarting GSS-proxy
Starting IPA services
Restarting SSSD
Restarting oddjobd
Restoring umask to 18
The ipa-restore command was successful

  5. Re-initialize all replicas connected to the restored server:

    1. List all replication topology segments for the domain suffix, taking note of topology segments involving the restored server. 

      [root@server1 ~]# ipa topologysegment-find domain
------------------
2 segments matched
------------------
  Segment name: server1.example.com-to-caReplica2.example.com
  Left node: server1.example.com
  Right node: caReplica2.example.com
  Connectivity: both

  Segment name: caReplica2.example.com-to-replica3.example.com
  Left node: caReplica2.example.com
  Right node: replica3.example.com
  Connectivity: both
----------------------------
Number of entries returned 2
----------------------------

    2. Re-initialize the domain suffix for all topology segments with the restored server.

      In this example, perform a re-initialization of caReplica2 with data from server1. 

      [root@caReplica2 ~]# ipa-replica-manage re-initialize --from=server1.example.com
Update in progress, 2 seconds elapsed
Update succeeded

    3. Moving on to Certificate Authority data, list all replication topology segments for the ca suffix. 

      [root@server1 ~]# ipa topologysegment-find ca
-----------------
1 segment matched
-----------------
  Segment name: server1.example.com-to-caReplica2.example.com
  Left node: server1.example.com
  Right node: caReplica2.example.com
  Connectivity: both
----------------------------
Number of entries returned 1
----------------------------

    4. Re-initialize all CA replicas connected to the restored server.

      In this example, perform a csreplica re-initialization of caReplica2 with data from server1. 

      [root@caReplica2 ~]# ipa-csreplica-manage re-initialize --from=server1.example.com
Directory Manager password:

Update in progress, 3 seconds elapsed
Update succeeded

  6. Continue moving outward through the replication topology, re-initializing successive replicas, until all servers have been updated with the data from restored server server1.example.com.

    In this example, we only have to re-initialize the domain suffix on replica3 with the data from caReplica2: 

    [root@replica3 ~]# ipa-replica-manage re-initialize --from=caReplica2.example.com
Directory Manager password:

Update in progress, 3 seconds elapsed
Update succeeded

  7. Clear SSSD’s cache on every server to avoid authentication problems due to invalid data:

    1. Stop the SSSD service: 

      [root@server ~]# systemctl stop sssd

    2. Remove all cached content from SSSD: 

      [root@server ~]# sss_cache -E

    3. Start the SSSD service: 

      [root@server ~]# systemctl start sssd
    4. Reboot the server.

Additional resources

  • The ipa-restore (1) man page also covers in detail how to handle complex replication scenarios during restoration.

5.4. Restoring from an encrypted backup

This procedure restores an IdM server from an encrypted IdM backup. The ipa-restore utility automatically detects if an IdM backup is encrypted and restores it using the GPG2 root keyring.

Prerequisites

Procedure

  1. If you used a custom keyring location when creating the GPG2 keys, verify that the $GNUPGHOME environment variable is set to that directory. See Creating a GPG2 key. 

    [root@server ~]# echo $GNUPGHOME
/root/backup

  2. Provide the ipa-restore utility with the backup directory location. 

    [root@server ~]# ipa-restore ipa-full-2020-01-13-18-30-54

    1. Enter the Directory Manager password. 

      Directory Manager (existing master) password:

    2. Enter the passphrase you used when creating the GPG key. 

      ┌────────────────────────────────────────────────────────────────┐
│ Please enter the passphrase to unlock the OpenPGP secret key:  │
│ "GPG User (first key) <root@example.com>"                      │
│ 2048-bit RSA key, ID BF28FFA302EF4557,                         │
│ created 2020-01-13.                                            │
│                                                                │
│                                                                │
│ Passphrase: <passphrase>                                       │
│                                                                │
│         <OK>                                    <Cancel>       │
└────────────────────────────────────────────────────────────────┘
  3. Re-initialize all replicas connected to the restored server. See Restoring an IdM server from backup.