Reverting an ONTAP cluster

To take the cluster offline to revert to an earlier ONTAP release, you must disable storage failover and the data LIFs, address reversion preconditions, revert the cluster and file system configurations on a node, and then repeat the process for each additional node in the cluster.

1. Set the privilege level from admin to advanced, entering y when prompted to continue: set -privilege advanced
   The advanced prompt (*>) appears.
2. Verify that the target ONTAP software is installed: system image show

   Example

   The following example shows that version 9.7 is installed as the alternate image on both nodes:

   TDC-DM7K::system*> image show
                    Is      Is                                Install
   Node     Image   Default Current Version                   Date
   -------- ------- ------- ------- ------------------------- -------------------
   TDC-7K-01
            image1  false   false   9.7P7                    11/5/2020 07:11:58
            image2  true    true    9.7P8                    11/6/2020 01:50:18
   TDC-7K-02
            image1  false   false   9.7P7                   11/5/2020 07:12:12
            image2  true    true    9.7P8                    11/6/2020 01:50:42
   4 entries were displayed.
   
3. Disable all of the data LIFs in the cluster: network interface modify {-role data} -status-admin down
4. If the cluster consists of only two nodes, disable cluster HA: cluster ha modify -configured false
5. Disable storage failover for the nodes in the HA pair from either node: storage failover modify -node nodename -enabled false

   You only need to disable storage failover once for the HA pair. When you disable storage failover for a node, storage failover is also disabled on the node's partner.
6. Log in to the node that you want to revert.

   To revert a node, you must be logged in to the cluster through the node's node management LIF.
7. Set the node's target ONTAP software image to be the default image: system image modify -node nodename -image target_image -isdefault true
8. Verify that the target ONTAP software image is set as the default image for the node that you are reverting: system image show

   Example

   The following example shows that version 9.7 is set as the default image on node0:

   TDC-DM7K::system*> image show
                    Is      Is                                Install
   Node     Image   Default Current Version                   Date
   -------- ------- ------- ------- ------------------------- -------------------
   TDC-7K-01
            image1  false   false   9.7P7                    11/5/2020 07:11:58
            image2  true    true    9.7P8                    11/6/2020 01:50:18
   TDC-7K-02
            image1  false   false   9.7P7                   11/5/2020 07:12:12
            image2  true    true    9.7P8                    11/6/2020 01:50:42
   4 entries were displayed.
   
9. If the cluster consists of only two nodes, verify that the node does not hold epsilon:
   1. Check whether the node currently holds epsilon: cluster show -node nodename

      Example

      The following example shows that the node holds epsilon:

      TDC-DM7K::*> cluster show -node TDC-7K-01
      
                Node: TDC-7K-01
                UUID: 9df34886-0ead-11eb-99fa-00a098dbdfca
             Epsilon: false
         Eligibility: true
              Health: true
      
   2. If the node holds epsilon, mark epsilon as false on the node so that epsilon can be transferred to the node's partner: cluster modify -node nodenameA -epsilon false
   3. Transfer epsilon to the node's partner by marking epsilon true on the partner node: cluster modify -node nodenameB -epsilon true
10. Verify that the node is ready for reversion: system node revert-to -node nodename -check-only true -version 9.x

    The check-only parameter identifies any preconditions that must be addressed before reverting, such as the following examples:

    • Disabling storage failover

    • Disabling the Snapshot policy

    • Deleting Snapshot copies that were created after upgrading to the later version of ONTAP

11. Verify that all of the preconditions have been addressed: system node revert-to -node nodename -check-only true -version 9.x
12. Revert the cluster configuration of the node: system node revert-to -node nodename -version 9.x

    The -version option refers to the target release. For example, if the software you installed and verified is ONTAP 9.8, the correct value of the -version option is 9.8 .
    The cluster configuration is reverted, and then you are logged out of the clustershell.
13. Log back in to the clustershell, and then switch to the nodeshell: run -node nodename

    After logging on the clustershell again, it might take a few minutes before it is ready to accept the nodeshell command. So, if the command fails, wait a few minutes and try it again.
14. Revert the file system configuration of the node: revert_to 9.x

    This command verifies that the node's file system configuration is ready to be reverted, and then reverts it. If any preconditions are identified, you must address them and then rerun the revert_to command.

    Note

    Using a system console to monitor the revert process displays greater details than seen in nodeshell.
    When the command finishes, the LOADER prompt is displayed.
15. Enter yes at prompt to revert.

    If AUTOBOOT is true, the node will reboot to ONTAP. If AUTOBOOT is false, the node will halt.
16. Repeat Steps 5 through 15 on the other node in the HA pair.
17. If the cluster consists of only two nodes, reenable cluster HA: cluster ha modify -configured true
18. Reenable storage failover on both nodes if it was previously disabled: storage failover modify -node nodename -enabled true
19. Repeat Steps 4 through 18 for each additional HA pair and both the clusters in MetroCluster Configuration.