Registering a PEM agent ======================= Before you can use a PEM agent, you must register it with a PEM server. **PEM agents installed by the PEM server package are registered automatically during server configuration.** For all other agents, follow these instructions. .. Note:: After upgrading the PEM agent, you need to restart it. You don't need to register it again. How to register PEM agents -------------------------- On Linux and Windows hosts, the PEM agent package includes a command line utility called pemworker. You can use it to perform management tasks, including :ref:`Registering a PEM agent using the pemworker utility ` . On Windows, the PEM agent graphical installer allows you to register the agent when installing it. This convenience option doesn’t support all the possibilities provided by the pemworker utility. If you don’t want the installer to register the agent, clear the **Register now** checkbox. For more details, see the `installation instructions `_ . Registering a PEM agent using the pemworker utility --------------------------------------------------- The pemworker utility is installed with the PEM agent. It’s located in ``/usr/edb/pem/agent/bin`` on Linux and ``C:\Program Files\edb\pem\agent-x64\bin`` on Windows. To register an agent, set the PEM server password, invoke the utility as shown in the examples, and add the relevant options from the table as needed. Follow each option with a corresponding value. Linux ^^^^^ .. code:: shell export PEM_SERVER_PASSWORD=edb # Running as root pemworker --register-agent Windows ^^^^^^^ .. code:: shell set PEM_SERVER_PASSWORD=edb # Running as admin ./pemworker.exe REGISTER .. csv-table:: :header: Option,Description :widths: 10,30 :align: left :class: longtable `--pem-server`,The IP address of the PEM backend database server. This parameter is required. `--pem-port`,The port of the PEM backend database server. The default value is `5432`. `--pem-user`,"The name of a database user with the pem_admin role and the `rolcreaterole` flag set on the PEM backend database server, or a superuser. This user will be used to connect to the PEM server to perform agent registration. This parameter is required." `--pem-agent-user`,"The name of a database user on the PEM backend database server. After registration, the agent will use this user to open connections to the PEM database server to write probe data, evaluate alerts, and so on. This parameter is optional. If omitted, the agent connects using a new user named `agent` created during registration, where `` is the agent ID. This user is always created. Even if you specify a `pem-agent-user`, the agent will use `SET ROLE agent` to switch roles after the connection is made." `--pem-ssl-mode`,"The `SSL mode `__ for the PEM agent user to use (see above). The possible values are `prefer`, `require`, `disable`, `verify-CA`, and `verify-full`. The default value is `require`." `--cert-path`,"The complete path to a directory in which to store certificates. If you don't provide a path, certificates are created in `~/.pem` on Linux and `%APPDATA%/pem` on Windows." `--config-dir`,The directory path for the configuration file. The default is `/../etc`. `--display-name`,"A user-friendly name for the agent to display in the PEM browser tree. In PEM 9.6 and later, the default is the host's fully qualified domain name (FQDN), falling back to the hostname if this option isn't set. For releases earlier than PEM 9.6, the default is the hostname." `--force-registration`,Include the `force-registration` clause to register the agent with the arguments provided. This clause is useful if you're overriding an existing agent configuration. The default value is `Yes`. `--group`,"The name of a group in which to place the agent. This parameter is optional. If omitted, the agent isn't placed in a group." `--team`,"The name of a database role on the PEM backend database server. Access to this agent is restricted to only the named role, the owner, and the pem_admin role. This parameter is optional. If omitted, no team is assigned, meaning all users can access this agent." `--owner`,"The name of a database user on the PEM backend database server. This user will be assigned as the owner of the agent. If omitted, the specified `pem-user` is assigned as the owner." `--allow_server_restart`,Allow PEM to restart the monitored server. The default value is `True`. `--allow-batch-probes`,Allow PEM to run batch probes on this agent. The default value is `False`. `--batch-script-user`,"The operating system user to use for executing the batch/shell scripts. The default value is none. If you leave this parameter blank or the specified user doesn't exist, the scripts don't execute." `--enable-heartbeat-connection`,Create a dedicated heartbeat connection between the PEM agent and server to update the active status. The default value is `False`. `--enable-smtp`,Allow the PEM agent to send the email on behalf of the PEM server. The default value is `False`. `--enable-snmp`,Allow the PEM agent to send the SNMP traps on behalf of the PEM server. The default value is `False`. `-o`,Override the configuration file options. See the following :ref:`Overriding default configurations - examples` for usage. .. Note Allowing the agent to restart the database server:: If you use any feature of PEM that requires a database server restart by the PEM agent (such as Audit Manager, Log Manager, or the Tuning Wizard), then you must set the value of `allow_server_restart` to `true` in the `agent.cfg` file or restart the server manually for changes to take effect. .. Note Running shell/batch jobs:: If you want to run shell/batch jobs using an agent, you must specify the user for the `batch_script_user` parameter. We strongly recommend that you use a non-root user to run the scripts. Using the root user might result in compromising the data security and operating system security. Authenticating the pemworker utility ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Before any changes are made on the PEM database, the connection is authenticated with the PEM database server. When invoking the pemworker utility, you must provide the password associated with the PEM server administrative user role (postgres). You can specify the administrative password in three ways: - Set the ``PEM_SERVER_PASSWORD`` environment variable. - Provide the password on the command line with the ``PGPASSWORD`` keyword. - Create an entry in the ``.pgpass`` file. If you don’t provide the password, a password authentication error occurs. After authentication succeeds, you’re prompted for any other missing required information. When the registration is complete, the server confirms that the agent was successfully registered. Unregistering a PEM agent ------------------------- You can use the pemworker utility to unregister a PEM agent. To unregister an agent, invoke the pemworker utility as shown in the examples that follow. .. _linux-1: Linux ^^^^^ .. code:: shell # Running as root pemworker --unregister-agent .. _windows-1: Windows ^^^^^^^ .. code:: shell ./pemworker.exe UNREGISTER-AGENT When invoking the pemworker utility, append command line options to the command string. Follow each option with a corresponding value. .. csv-table:: :header: Option,Description :widths: 10,30 :align: left :class: longtable `--pem-user `,The name of the database user (member of pem_admin role) of the PEM backend database server. This parameter is required. `--config-dir`,"The directory path for the configuration file. The default is `""/../etc""`." Advanced usage -------------- The following are some advanced options for PEM agent registration. Setting the agent ID ^^^^^^^^^^^^^^^^^^^^ Each registered PEM agent must have a unique agent ID. The value ``max(id)+1`` is assigned to each agent ID unless a value is provided using the ``-o`` options as shown :ref:`Overriding default configurations - examples ` . Overriding default configurations - examples ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This example shows how to register the PEM agent and override the default configurations. .. _setting-the-agent-id-1: Setting the agent ID ^^^^^^^^^^^^^^^^^^^^ Register the PEM agent using the command line. Assign an ``agent_id`` value of 8 using the ``-o`` option. .. code:: shell # Running as root /usr/edb/pem/agent/bin/pemworker --register-agent \ - -pem-server pemserver \ - -pem-user postgres \ - -pem-port 5432 \ - -display-name agent8 \ - o agent_id=8 __OUTPUT__ Postgres Enterprise Manager Agent registered successfully! Because the ``agent_id`` of 8 is available, the PEM agent registers successfully. If the given ID is already in use by the existing agent, an error occurs. Providing an existing SSL certificate and key ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Register the PEM agent using the command line. Assign the existing SSL certificates and key files to avoid generating new ones for a particular agent ID. The SSL certificates and key files must be valid for the database user ``agent`` , where ```` must be the same as provided using the command line. Use the ``-o`` option. .. code:: shell # Running as root # List the location of valid SSL certificates and key files. ls -l /root/.pem/agent5.* - rw------- 1 root root 2192 Nov 7 11:27 /root/.pem/agent5.crt - rw------- 1 root root 3244 Nov 7 11:27 /root/.pem/agent5.key # Register the PEM agent using command line. Assign the # SSL certificates and key files using the -o option. /usr/edb/pem/agent/bin/pemworker --register-agent \ - -pem-server pemserver \ - -pem-user postgres \ - -pem-port 5432 \ - -config-dir /tmp/pem-config \ - -display-name agent5 \ - o agent_id=5 \ - o agent_ssl_crt=/root/.pem/agent5.crt \ - o agent_ssl_key=/root/.pem/agent5.key __OUTPUT__ Postgres Enterprise Manager Agent registered successfully! Because the valid SSL certificates and key files are available at the given location with proper permissions, the PEM agent registers successfully. If the certificate or key files aren’t valid or don’t have proper permissions, an error occurs. Using a non-root user account to register a PEM agent on Linux ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ To use a non-root user account to register a PEM agent, you must first install the PEM agent as a root user. After installation, assume the identity of a non-root user, such as edb. Then: 1. Log in as edb. Create ``pem`` and ``logs`` directories and assign read, write, and execute permissions: .. code:: shell # Running as nonroot user edb mkdir /home/edb/pem mkdir /home/edb/pem/logs chmod 700 /home/edb/pem chmod 700 /home/edb/pem/logs 2. Register the agent with PEM server: .. code:: shell export PEM_SERVER_PASSWORD=edb # Use the following command to create agent certificates and an agent # configuration file (`agent.cfg`) in the `/home/edb/pem` directory. /usr/edb/pem/agent/bin/pemworker --register-agent --pem-server <172.19.11.230> --pem-user postgres --pem-port 5432 --display-name non_root_pem_agent --cert-path /home/edb/pem --config-dir /home/edb/pem # Use the following command to assign read and write permissions to # these files: chmod -R 600 /home/edb/pem/agent* 3. Change the parameters of the ``agent.cfg`` file: .. code:: ini vi /home/edb/pem/agent.cfg agent_ssl_key=/home/edb/pem/agent.key agent_ssl_crt=/home/edb/pem/agent.crt log_location=/home/edb/pem/worker.log agent_log_location=/home/edb/pem/agent.log Where ```` is the assigned PEM agent ID. 4. Create a ``tmp`` directory, set the environment variable, and start the agent: .. code:: ini mkdir /home/edb/pem/tmp # Create a script file, add the environment variable, give permissions, and execute: vi /home/edb/pem/run_pemagent.sh #!/bin/bash export TEMP=/home/edb/agent/tmp /usr/edb/pem/agent/bin/pemagent -c /home/edb/agent/agent.cfg chmod a+x /home/edb/pem/run_pemagent.sh cd /home/edb/pem ./run_pemagent.sh Your PEM agent is now registered and started with the edb user. If your machine restarts, then this agent doesn’t restart automatically. You need to start it manually using the previous command. 5. Optionally, you can create the service for this PEM agent as the root user to start this agent automatically at machine restart as follows: a. Update the values for the configuration file path and the user in the ``pemagent`` service file as superuser: .. code:: ini # Running as superuser sudo vi /usr/lib/systemd/system/pemagent.service [Service] Type=forking WorkingDirectory=/home/edb/pem Environment=LD_LIBRARY_PATH=/usr/edb/pem/agent/lib:/usr/libexec/edb-snmp++/lib Environment=TEMP=/home/edb/pem/tmp ExecStart=/usr/edb/pem/agent/bin/pemagent -c /home/edb/pem/agent.cfg b. Stop the running agent process and restart the agent service: .. code:: shell # Find the process id of the running pem agent and pem worker process and kill that process ps -ax | grep pemagent kill -9 ps -ax | grep pemworker kill -9 # Enable and start pemagent service sudo systemctl enable pemagent sudo systemctl start pemagent sudo systemctl status pemagent 6. Check the agent status on the PEM dashboard. .. Note:: - Any probes and jobs that require root permission or access to a file owned by another user (for example, enterprisedb) fail. - If you move the `agent.cfg` file from its default location to another, the PEM dashboard might display the agent status as `unknown` . See :ref:`Troubleshooting agent issues ` for more information.