Symptoms

Attempt to add new Windows node to OA fails with the following error:

Task ID 8796319
Queue name      win_node_regist_WINWEB01_WIN_GENERIC
Task name       Install PA agent on node 'WINWEB01'
Task description        Install PA agent on node 'WINWEB01'
Queue status    Failed
Start not earlier than  Mar-27-2015 12:56
Method name     taskInstallAgent on OBJREF:SharedNodeRegistrator:0:WindowsNodeRegistratorPrivate:0
Last execution output   Failed to execute command 'PAgent.exe'. Check logs in 'c:\POA_Deploy' at host '192.168.1.100' for more details about the reasons of failure.

The following messages can be found in installation log of OA agent located in C:\POA_Deploy folder:

MSI (s) (C0:AC) [12:51:56:206]: Invoking remote custom action. DLL: C:\Windows\Installer\MSIBA6F.tmp, Entrypoint: registerHost
POA Log: "C:\Program Files (x86)\SWsoft\PEM\bin\Register_Host.exe" "-r" "corbaloc:iiop:10.1.2.3:8354/ObjectResolver" "-H" "267" "-OrbSvcConf" "C:\Program Files (x86)\SWsoft\PEM\etc\svc.conf" "-t" "4D371DBC-D478-11E4-8000-67C6697351FF" "-x" "C:\Program Files (x86)\SWsoft\PEM\etc\peers.conf" "-h" "WINWEB01.HOSTING.LOCAL" "-u" "WINWEB01" "-d" "C:\Program Files (x86)\SWsoft\PEM" "-a" "X.X.X.X" "-A" "Y.Y.Y.Y" "-P" "8352" "-S" "Win32" "-N" "WINWEB01.HOSTING.LOCAL" "-B" "WINWEB01" "-D" "HOSTING" "-b" "HOSTING.LOCAL" "-s" "C:\CustomerData" "-z" "pem_domain" "-Z" "**********" "-y" "pem_admin" "-Y" "**********" "-c" "PEM_network_share_name" "-C" "x86_64" "-R" "6.1" 
...
MSI (s) (C0!E8) [12:51:56:695]: Product: POA Agent -- POA Error: Registration host error. Host #zzz with similar properties already exists.: SIMILAR_HOST_ALREADY_EXISTS.
(ExSystem) errcode = 0
Unauthenticated call to IDL:psa.parallels.com/Host:1.0::getHostByName. CORBA sessions must be authenticated using hub::acquire_own_cred. 0:10404:4798:7: RET_FAILURE_EX_SYSTEM.
ACE_Thread::setspecific() failed!: Resource temporarily unavailable

Same error can be found in OA main system log:

Mar 30 16:47:53 osscore001 : DBG [0:12956:2434:4 1:14733:ac8efb90 Kernel]: STMT [Con: 15227, 0xb1e16a68 txn:668181] ' SELECT  host_id, rt_instance_id, platform_id FROM hosts WHERE primary_name =  ?'($0 = 'WINWEB01.HOSTING.LOCAL')
Mar 30 16:47:53 osscore001 : DBG [0:12956:2434:4 1:14742:ae9f3b90 lib]: [txn:668181 void<unnamed>::checkSimilarHostExists] {module_id="HostManager"; code="26"} Host #zzz with similar properties already exists.

Cause

The host with the mentioned hostname indeed exists in OA. it can be checked by executing the query from the log shown above:

plesk=> SELECT  host_id, rt_instance_id, platform_id FROM hosts WHERE primary_name = 'WINWEB01.HOSTING.LOCAL';
host_id | rt_instance_id | platform_id
---------+----------------+-------------
     470 |            267 |         101
(1 row)

Such situation could occur if there were several attempts to add / remove this node.

Resolution

1. Go to Infrastructure > Service Nodes and remove the node WINWEB01 from the list, check that related tasks are processed.
2. Re-run the initial failed task, it should be completed successfully.
3. If the task fails, check OA main system log as well as agent-installation log once again to troubleshoot the issue further.

NOTE: if the removal task fails with The remote server is temporarily down. Please, make sure that destination host is accessible from POA management node and POA agent is running there, please troubleshoot the issue according to the article How to fix an unmanageable POA-managed server.