Here are some steps necessary to enable clustering...

Passwords

When deploying in Production Mode, WebLogic will ask for a username and password before starting.

To automate startup, create a "security" folder in the server directory of the domain. Inside it, create a "boot.properties" file.

Example:

mkdir -p ./servers/AdminServer/security
echo "username=weblogic" >> ./servers/AdminServer/security/boot.properties
echo "password=weblogic123" >> ./servers/AdminServer/security/boot.properties

Don't worry. Upon startup, the username and password will become encrypted.

Node Manager

Steps to create a WebLogic Systemd startup script...

Properties File

A file "nodemanager.properties" will be automatically created when you run the script "./startNodeManager.sh".

Hit ctl+c to kill the process. Now we can edit the "nodemanager.properties" file.

Change Listen Address

Change the listen address from 'localhost' to a reachable IP address.

# ListenAddress=localhost
ListenAddress=0.0.0.0

Disable Start Script

In WebLogic 12.1.1 (and higher), the nodemanager has been modified to user the "startWebLogic.sh" script to launch WebLogic. I prefer the old technique because it allows creating custom startup parameters for each server.

# StartScriptEnabled=true
StartScriptEnabled=false

Systemd Startup Scripts

Create a file called "/etc/systemd/system/nodemanager.service".

[Unit]
Description=WebLogic Node Manager Service

[Service]
Type=simple
# Note that the following three parameters should be changed to the correct paths
# on your own system
WorkingDirectory=/home/oracle/wsc72/user_projects/domains/replicated_domain
ExecStart=/home/oracle/wsc72/user_projects/domains/replicated_domain/bin/startNodeManager.sh
ExecStop=/home/oracle/wsc72/user_projects/domains/replicated_domain/bin/stopNodeManager.sh
User=oracle
Group=oinstall
KillMode=process
LimitNOFILE=65535

[Install]
WantedBy=multi-user.target

You can now use the following commands to start / stop nodemanager:

sudo systemctl enable nodemanager
sudo systemctl start nodemanager

Admin Console

Let's create a startup script for the Admin Console as well...

Create a file called "/etc/systemd/system/weblogic.service".

[Unit]
Description=WebLogic Admin Console Service

[Service]
Type=simple
# Note that the following three parameters should be changed to the correct paths
# on your own system
WorkingDirectory=/home/oracle/wsc72/user_projects/domains/replicated_domain
ExecStart=/home/oracle/wsc72/user_projects/domains/replicated_domain/bin/startWebLogic.sh
ExecStop=/home/oracle/wsc72/user_projects/domains/replicated_domain/bin/stopWebLogic.sh
User=oracle
Group=oinstall
KillMode=process
LimitNOFILE=65535

[Install]
WantedBy=multi-user.target

You c

Admin Console

Now we need to make some configuration changes to the domain. The best way to do this is from the Admin Console.

Create Machines

In the WebLogic Admin Console, create 'machines' to logically represent each physical server (VM or bare-metal) the WebLogic Managed Server will be running on.

Assign the "Node Manager Listen Address". This will be the IP Address that the Admin Console will use to contact the node manager. (It can't be 0.0.0.0.)

Create Dynamic Clusters

Troubleshooting

Here are a few 'gotchas' discovered over the years...

Multicast

Use of multicast for clustering is more efficient than 'unicast', but it can lead to some configuration heartache.

If you get an error similar to:

Solve the problem by telling WebLogic to prefer the IPv4 stack.

You can use the Multicast Monitor to check that heartbeat messages are being sent or received. Run this on any or all WebLogic servers:

java weblogic.cluster.MulticastMonitor <multicast_address> <multicast_port> <domain_name> <cluster_name>

Example:

source setDomainEnv.sh
java weblogic.cluster.MulticastMonitor 239.192.0.0 7001 replicated_domain BEA_ENGINE_TIER_CLUST

Node Manager