Weblogic 12c Nodemanager - some Basics, some Differences

As I write this blog, many companies have already moved to the 12c version of SOA. With the latest SOA version comes new features like internet of things with event based processing, the support for mobile and cloud. But for a certain section of people, FMW admins like me, day to day technical operations matter most.

 

I'll be taking some important aspects of managing nodemanager(NM from here on) of the 12c weblogic, and also highlight some subtle changes in 12c node manager, which a person responsible for managing the weblogic should be aware of.

 

 

1.     11g to 12c changes

Pre 12.1.2	Post 12.1.2/12.1.3
Option of per machine & per domain NM, with per machine being default one.	Per domain is the default, and per machine NM needs a bit of configuration. Refer# https://tinyurl.com/q8g6mr8
Default logs are found at : $WL_HOME/common/nodemanager/logs	Default logs are found at : $DOMAIN_HOME/nodemanager/logs
In 11g, we required 1 NM for Admin server domain path & 1 NM for managed server domain path, as the nodemanager.domains file has only 1 path per domain e.g. for 11g: domain-name=domain-directory	1 domain level NM is sufficient when Admin server is on SAN, out of DOMAIN_DIR https://tinyurl.com/nu2zlkv e.g. for 12c: domainName=primaryDomainPath; alternateDomainPath1; alternateDomainPath2
No script to stop the NM, one needs to kill NM process	stopNodeManager.sh script is available

 

 

 

2.     Starting the NM

The regular way to start the domain specific NM, is to start using following command:

nohup $DOMAIN_HOME/bin/startNodeManager.sh &

Though this should work for most of the cases, this isn’t an ideal nail to go in your production kit.

For production env, always configure the NM as init.d or xinetd service, so that the node manager comes up automatically every time your server reboots. Follow the below steps given in oracle documentation to achieve this.

http://docs.oracle.com/middleware/1213/wls/NODEM/java_nodemgr.htm#NODEM247

·         A word about oracle documentation for setting up nodemanager init.d service

The script given in oracle document tends to start the NM as root, which will definitely cause issues. So you must make the below changes in oracle script, in the link shared above, to start NM as non-root user-

 

Make the following changes:

 

$PROGRAM_START >> $OUT_FILE 2>&1  &

To

su -c $“<<USE_NM_USER>>” $PROGRAM_START >> $OUT_FILE 2>&1  &

 

 

 

 

3.     Change the password for managing nodemanager

Not many would know that you we can password for starting/stopping weblogic servers need not to same as that for managing NM. This also makes a strong case security point too.

You can update the NM password by accessing Admin console. NO restart is required for change to get reflected.

The steps for doing so are readily available from oracle documentation so I will simply share the link instead of typing it here again

Refer: http://docs.oracle.com/cloud/latest/fmw121300/NODEM/java_nodemgr.htm#NODEM161

 

 

 

·         A word of caution while changing nodemanager credentials

 

You may change the password for the accessing NM services, and you can technically speaking change even the username from “weblogic” to something else. BUT after doing so, you’ll not be able to use the credential key file (which you can create with wlst storeUserConfig(), for password less authentication), for connecting to WLST.

 

More about working with WLST and nodemanager in another post.

Continue to SeeITwithSanjay!