ZDLRA.ra_install.jar. Exception in thread "main" java.lang.IllegalStateException: Already connected or RMAN kbhssrGetSbtParms:OCIStmtExecute

Installing backup module (ra_install.jar) i obtained one strange error :

-bash-4.2$ /oracle/app/db12c/OPatch/jre/bin/java -jar /oracle/zdlra/ra_install.jar -dbUser ravpc1 -dbPass welcome1 -host ed05-scan.52.s -port 1521 -servicename zdlra -walletDir $ORACLE_HOME/dbs/ra_wallet -configFile $ORACLE_HOME/dbs/rachordprd1.ora -libDir $ORACLE_HOME/lib
Recovery Appliance Install Tool, build 12.2.0.1.0DBBKPCSBP_2017-11-28
Recovery Appliance credentials are valid.
Recovery Appliance wallet created in directory /oracle/app/db12c/dbs/ra_wallet.
Recovery Appliance initialization file /oracle/app/db12c/dbs/rachordprd1.ora created.
Downloading Recovery Appliance Software Library from file ra_linux64.zip.
  Error: Library download failed. Please check your network connection to Oracle Public Cloud.
Retry download from Recovery Appliance.
Downloading Recovery Appliance Software Library from file ra_linux64.zip.
Exception in thread "main" java.lang.IllegalStateException: Already connected
        at sun.net.www.protocol.http.HttpURLConnection.setRequestProperty(HttpURLConnection.java:3014)
        at oracle.backup.util.FileDownload.addDigestAuthHeader(FileDownload.java:699)
        at oracle.backup.util.FileDownload.addHttpAuthHeader(FileDownload.java:166)
        at oracle.backup.util.FileDownload.addHttpAuthHeader(FileDownload.java:138)
        at oracle.backup.util.FileDownload.download(FileDownload.java:418)
        at oracle.backup.util.ConfigSetup.downloadLibrary(ConfigSetup.java:452)
        at oracle.backup.ba.install.BaConfig.downloadLibrary(BaConfig.java:352)
        at oracle.backup.ba.install.BaConfig.main(BaConfig.java:155)

All paramters are correct, we checked is many times.
We checked the network connectivity, checked the firewall, did nslookup for all hosts for direct and reverse zones: all is correct !

But rman backups were working some times!
Some times the backup finished successfully, but some times backup got the error:

For example:
RMAN> RUN
2> {
3> ALLOCATE CHANNEL ch1 DEVICE TYPE sbt_tape
4> PARMS='SBT_LIBRARY=/oracle/app/db12c/lib/libra.so,
5> ENV=(RA_WALLET=LOCATION=file:/oracle/zdlra CREDENTIAL_ALIAS=ed05-scan.52.s:1521/zdlra)'  FORMAT '%U_%d';
6> #backup current controlfile;
7> BACKUP INCREMENTAL LEVEL 1 DATABASE ;
8> }
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03009: failure of allocate command on ch1 channel at 05/15/2018 14:19:27
ORA-19554: error allocating device, device type: SBT_TAPE, device name:
ORA-27023: skgfqsbi: media manager protocol error
ORA-19511: non RMAN, but media manager or vendor specific failure, error text:
   KBHS-01409: Oracle error reported from Recovery Appliance while executing kbhssrGetSbtParms:OCIStmtExecute
ORA-24324: service handle not initialized
KBHS-01412: failed for connection RAVPC1 (@ed05-scan.52.s:1521/zdlra)



We decided to stop one of nodes.
And while 2nd node is stopped and 1st node is running this error disappeared.
When 2nd node is working and 1st node is down - we always get error.


Diagnostics:
SQL> select * from rai_host;

NODE_NAME
--------------------------------------------------------------------------------
ADMIN_IP_ADDRESS
--------------------------------------------------------------------------------
BACKUP_IP_ADDRESS
--------------------------------------------------------------------------------
REPLICATION_IP_ADDRESS
--------------------------------------------------------------------------------
ed05dbadm02
172.31.8.177
10.35.60.243

ed05dbadm01.distr.fors.ru
172.31.8.176
10.35.60.241


There is difference in host names.


And the solution is obvious:

$ sqlplus rasys/welcome1

SQL> update rai_host set NODE_NAME='ed05dbadm02.distr.fors.ru' where ADMIN_IP_ADDRESS='172.31.8.177';

1 row updated.

SQL> commit  ;

Commit complete.

SQL> select * from rai_host;

NODE_NAME
--------------------------------------------------------------------------------
ADMIN_IP_ADDRESS
--------------------------------------------------------------------------------
BACKUP_IP_ADDRESS
--------------------------------------------------------------------------------
REPLICATION_IP_ADDRESS
--------------------------------------------------------------------------------
ed05dbadm02.distr.fors.ru
172.31.8.177
10.35.60.243

ed05dbadm01.distr.fors.ru
172.31.8.176
10.35.60.241