How to change dbsnmp password in 11gR2 RAC?

Environment:  
Oracle   3-nodes RAC 11.2.0.2


Problem: 
EM user dbsnmp password was messed up, so EM failed to get agent information, then lock the dbsnmp user. So we need reset to the correct password.

Solution:

Step 1). On all nodes, stop EM.

$emctl stop dbconsole

Step 2). On each node, e.g host #1 (host01),
cd  /u01/app/oracle/product/11.2.0/host01_<DBNAME>/sysman/emd

vi targets.xml

There are two changes, one for oracle_database, the other for rac_database.

change 1)

VALUE="****" changed to VALUE="PASSWORD"

change 2)
ENCRYPTED="TRUE" changed to ENCRYPTED="FALSE"

For example,

1)

<Target TYPE="oracle_database" NAME="DBNAME_INSTANCE2">

........

       <Property NAME="UserName" VALUE="d12147da3ed00cb9" ENCRYPTED="TRUE"/>

       <Property NAME="password" VALUE="PASSWORD" ENCRYPTED="FALSE"/>

2)

<Target TYPE="rac_database" NAME="DBNAME">

........

       <Property NAME="UserName" VALUE="d12147da3ed00cb9" ENCRYPTED="TRUE"/>

       <Property NAME="password" VALUE="PASSWORD" ENCRYPTED="FALSE"/>

Also did the same steps on the following configuration files,

vi /u01/app/oracle/product/11.2.0/host02_DBNAME/sysman/emd/targets.xml

vi /u01/app/oracle/product/11.2.0/host03_DBNAME/sysman/emd/targets.xml

repeat the above steps,

Step 3)After everything is changed, changed the dbsnmp password and unlock the user,

SQL> alter user dbsnmp identified by PASSWORD;

SQL> alter user dbsnmp account unlock; User altered.

Step 4)  Restart the EM

$ emctl start dbconsole

Step 5) Go to node2 and node3, repeat the above step

All EMs would be fine now.