This article explains how to replace node1 in a cluster with an IDP database

When Node1 is to be replaced in a cluster, configurations cannot be added directly, as it won't let you commit the configuration without the IDP database.

When a device is in a cluster, the IDP database can be pushed from the PRIMARY node only.

1. Update the Junos version to match the other Node0's Junos version.
2. Change the "root" password to the same "root" password as Node0.
3. Add all required licenses.
4. Install IDP database and other databases (if required).
   1. Offline update - https://supportportal.juniper.net/s/article/SRXIDP-Installing-IDP-signature-database-on-devices-in-a-cluster
5. Enable the cluster on the device, and reboot the device - "set chassis cluster cluster-id <> node 1 reboot" (Make sure that the cluster-id matches the node0's cluster-id. This command is to run in OPERATIONAL/CLI mode)
   1. **Add the configuration to the device:
      1. Make sure the config is in "set" format.
      2. Save the file in .txt format
      3. Transfer the file to /var/tmp/directory
      4. Delete the config - "delete" and type "yes"
      5. load the config using the command "load set /var/tmp/<file_name>"
      6. commit the config.
   2. Make sure "preempt" is disabled: (on both active node and Replacement)
      1. Look for "set chassis cluster redundancy-group <group-number> preempt"
      2. Delete this statement if present
6. Power down the device.
7. Connect all cables
8. Power on the device