:_mod-docs-content-type: PROCEDURE
[id="maintaining-instance-ha-functionality-after-adoption_{context}"]

= Maintaining the Instance HA functionality after adoption

[role="_abstract"]
To maintain the high availability for Compute instances (Instance HA) functionality after you adopt {rhos_long_noacro} {rhos_curr_ver}, create a fencing configuration file to use in your adopted environment.

.Procedure

. Gather the fencing information from the `fencing.yaml` file in your {rhos_prev_long} ({OpenStackShort}) {rhos_prev_ver} cluster.

. Retrieve the {OpenStackShort} {rhos_prev_ver} stonith configuration from any of your overcloud Controller nodes:
+
----
$ sudo pcs config
----
+
----
Stonith Devices:
...
  Resource: stonith-fence_ipmilan-525400dde4f7 (class=stonith
      type=fence_ipmilan)
    Attributes: stonith-fence_ipmilan-525400dde4f7-instance_attributes
      delay=20
      ipaddr=172.16.0.1
      ipport=6231
      lanplus=true
      login=admin
      passwd=password
      pcmk_host_list=compute-1
    Operations:
      monitor: stonith-fence_ipmilan-525400dde4f7-monitor-interval-60s
        interval=60s
  Resource: stonith-fence_ipmilan-525400819ad3 (class=stonith
      type=fence_ipmilan)
    Attributes: stonith-fence_ipmilan-525400819ad3-instance_attributes
      delay=20
      ipaddr=172.16.0.1
      ipport=6230
      lanplus=true
      login=admin
      passwd=password
      pcmk_host_list=compute-0
    Operations:
      monitor: stonith-fence_ipmilan-525400819ad3-monitor-interval-60s
        interval=60s
...
----

. Generate the fencing configuration file:
+
* To install the script that automatically generates this file, see link:https://access.redhat.com/solutions/7123932[How do I automatically generate fencing secret for RHOSO18 instanceha from a osp17.1 cluster that I want to adopt?].
* To create the fencing configuration file manually, see link:{ha-for-instances}/assembly_deploying-and-configuring-the-high-availability-for-compute-instances-service_instance-ha#proc_configuring-the-fencing-of-compute-nodes_instance-ha[Configuring the fencing of Compute nodes] in _Configuring high availability for instances_.