Running multiple PEM agent services on a single server v10.4

You can run more than one PEM agent service on a single server. While migrating, running multiple EDB Postgres Enterprise Manager (PEM) agents per database server is standard practice.

Each agent service runs as a separate process with its own configuration file, SSL certificates, and system service. All agents report independently to the same PEM server.

Prerequisites

• The PEM agent package is installed on the host.
• You have root or administrator access on the host.
• The PEM server is accessible from the host.

Linux

Register each additional agent

Each agent instance needs its own configuration directory and SSL certificate directory. Use --config-dir and --cert-path to specify separate directories for each agent.

1. Create a directory for the additional agent's configuration and certificates:

   → WrapCopy

   mkdir -p /etc/edb/pem/agent2/etc
   mkdir -p /root/.pem/agent2
   chmod 700 /root/.pem/agent2

2. Register the additional agent, specifying the new configuration directory and certificate path:

   → WrapCopy

   export PEM_SERVER_PASSWORD=<pem_admin_password>
   
   /usr/edb/pem/agent/bin/pemworker --register-agent \
     --pem-server <new-pem-server-ip> \
     --pem-port 5432 \
     --pem-user enterprisedb \
     --display-name "agent-host1-2" \
     --config-dir /etc/edb/pem/agent2/etc \
     --cert-path /root/.pem/agent2

   PEM assigns a unique agent ID automatically. The agent.cfg file and SSL certificates are created in the directories you specified.

3. Update the log file paths in the new agent.cfg to avoid conflicts with the default agent:

   → WrapCopy

   vi /etc/edb/pem/agent2/etc/agent.cfg

   Set log_location and agent_log_location to unique paths, for example:

   → WrapCopy

   log_location=/var/log/pem/agent2-worker.log
   agent_log_location=/var/log/pem/agent2.log

Create a systemd service for each additional agent

The default pemagent service runs the agent using its default configuration directory. To run an additional agent, create a new service unit file that points to the additional agent's configuration.

1. Copy the default service file:

   → WrapCopy

   cp /usr/lib/systemd/system/pemagent.service \
      /usr/lib/systemd/system/pemagent2.service

2. Edit the new service file and update ExecStart to use the new configuration directory:

   → WrapCopy

   vi /usr/lib/systemd/system/pemagent2.service

   Update the ExecStart line to pass the -c flag with the path to the new agent.cfg:

   → WrapCopy

   ExecStart=/usr/edb/pem/agent/bin/pemagent -c /etc/edb/pem/agent2/etc/agent.cfg

3. Reload the systemd daemon to pick up the new service file:

   → WrapCopy

   systemctl daemon-reload

4. Enable and start the new agent service:

   → WrapCopy

   systemctl enable --now pemagent2

5. Verify that the service is running:

   → WrapCopy

   systemctl status pemagent2

Repeat these steps for each additional agent service you want to run on the same host. Use distinct directory paths, log file paths, and service names for each one (for example, agent3, pemagent3.service, and so on).

Windows

Running multiple PEM agent services on a single Windows server isn't supported.

Verify agent registration

After starting each agent service, confirm that all agents are registered and active in the PEM web application.

1. In the PEM browser, expand PEM Server Directory > PEM Agents in the Object Explorer.
2. Confirm that each agent appears with an Active status.
3. Check the agent log files for connection or authentication errors.

You can also use the verify-registration subcommand to validate each agent:

pemworker --verify-registration --config-dir /etc/edb/pem/agent2/etc

See Registering a PEM agent for details on exit codes and additional options.