Quando instalamos o EMCC, ele usa o hostname do servidor em vários arquivos de configuração, que por sua vez são utilizados para as operações do EM, como deploy e comunicação dos agentes.

Neste cenário, o EM havia sido instalado em um servidor com nome oem.localdomain, posteriormente um servidor de DNS com domínio dibiei.com foi configurado no homelab. O hostname do servidor do EM foi alterado para oem.dibiei.com, de forma que pudesse ser resolvido pelo DNS.

Além de alterar o hostname do Linux, é necessário reconfigurar o EM para usar o novo hostname. Neste post será apresentado como realizar essa reconfiguração em 7 passos.

OBS1: Os agentes que apontam para o nome antigo precisão ser ajustados para apontar para o nome novo, este post não aborda essa configuração no agente.

OBS2: Se o ambiente for virtualizado, é recomendado criar um snapshot da VM.

Informações do ambiente:

Oracle Enterprise Manager Cloud Control 13.4.0.5

OMS HOME: /u02/middleware

INSTANCE HOME: /u02/gc_inst

1) Configurando variáveis de ambiente

$ export OMS_HOME=/u02/middleware
$ export PATH=$OMS_HOME/bin:$PATH

2) Backup do diretório gc_inst e do arquivo emInstanceMapping.properties:

$ zip -r /home/oracle/gc_inst.zip -d /u02/gc_inst
$ cp $OMS_HOME/sysman/config/emInstanceMapping.properties /home/oracle

3) Pare o OMS

$ emctl stop oms -all

4) Exporte as configurações do OMS

$ emctl exportconfig oms -dir /home/oracle

5) Exclua o diretório gc_inst e o arquivo emInstanceMapping.properties

$ rm -rf $OMS_HOME/sysman/config/emInstanceMapping.properties
$ rm -rf /u02/gc_inst

6) Recupere o backup alterando o hostname:

$ omsca recover -NOSTART -BACKUP_FILE /home/oracle/opf_ADMIN_20200927_120519.bka -AS_HOST oem.dibiei.com -EM_INSTANCE_HOST oem.dibiei.com -AS -MS

Será solicitado as senhas do usuário sysman assim como a senha do repositório. Abaixo um exemplo da saída do comando.

Oracle Enterprise Manager Cloud Control 13c Release 13.4.0.0.0
Copyright (c) 1996, 2020, Oracle. All rights reserved.
log4j:WARN No appenders could be found for logger (emctl.secure.oms.SecureOMSCmds).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
Recovered Instance Host name used from command line argument : oem.dibiei.com
OS check passed.
OMS version check passed.
Performing Admin Server Recovery...
Retrieved Admin Server template.
Source Instance Host name where configuration is exported : oem.localdomain
instHost name retrieved from local host name : oem.dibiei.com
Populated install params from backup...
Enter Administration Server user password:
Confirm Password:
Enter Node Manager Password:
Confirm Password:
Enter Repository database user password:
Enter Agent Registration password:
Confirm Password:
Doing pre requisite checks ......
Pre requisite checks completed successfully

Checking Plugin software bits
Proceed to recovery
Setting up domain from template...
Setup EM infrastructure succeeded!
Admin Server recovered from backup.
Now performing cleanup of OMS EMGC_OMS1...
Now launching DeleteOMS...
OMS Deleted successfully

Delete finished successfully
Now launching AddOMS...
Infrastructure setup of EM completed successfully.

Doing pre deployment operations ......
Pre deployment of EM completed successfully.

Deploying EM ......
Creating Data source first !!
Deployment of EM completed successfully.

Configuring webtier ......
Configuring webTier completed successfully.

Importing OMS configuration from recovery file...

If you have software library configured 
please make sure it is functional and accessible 
from this OMS by visiting:
 Setup->Provisioning and Patching->Software Library

Importing configuration for pluggable modules...
Securing OMS ......
Adapter already exists: emgc_USER
Adapter created successfully: emgc_GROUP
Post "Deploy and Repos Setup" operations completed successfully.

Performing Post deploy operations ....
Total 0 errors, 86 warnings. 0 entities imported.
pluginID:oracle.sysman.core
Done with csg import
pluginID:oracle.sysman.core
Done with csg import
pluginID:oracle.sysman.core
Done with csg import
pluginID:oracle.sysman.core
Done with csg import
No logging has been configured and default agent logging support is unavailable.
Post deploy operations completed successfully.

EM configuration completed successfully.
EM URL is:https://oem.dibiei.com:7803/em

Add OMS finished successfully
Recovery of server EMGC_OMS1 completed successfully
OMSCA Recover completed successfully

7) Inicie o OMS

emctl start oms