15.2. Applying a remote logging solution by using the logging RHEL system role

Procedure

1. Create a playbook file, for example, ~/playbook.yml, with the following content:

   ---
   - name: Deploy the logging solution
     hosts: managed-node-01.example.com
     tasks:
       - name: Configure the server to receive remote input
         ansible.builtin.include_role:
           name: redhat.rhel_system_roles.logging
         vars:
           logging_inputs:
             - name: remote_udp_input
               type: remote
               udp_ports: [ 601 ]
             - name: remote_tcp_input
               type: remote
               tcp_ports: [ 601 ]
           logging_outputs:
             - name: remote_files_output
               type: remote_files
           logging_flows:
             - name: flow_0
               inputs: [remote_udp_input, remote_tcp_input]
               outputs: [remote_files_output]
   
   - name: Deploy the logging solution
     hosts: managed-node-02.example.com
     tasks:
       - name: Configure the server to output the logs to local files in directories named by remote host names
         ansible.builtin.include_role:
           name: redhat.rhel_system_roles.logging
         vars:
           logging_inputs:
             - name: basic_input
               type: basics
           logging_outputs:
             - name: forward_output0
               type: forwards
               severity: info
               target: <host1.example.com>
               udp_port: 601
             - name: forward_output1
               type: forwards
               facility: mail
               target: <host1.example.com>
               tcp_port: 601
           logging_flows:
             - name: flows0
               inputs: [basic_input]
               outputs: [forward_output0, forward_output1]

   The settings specified in the first play of the example playbook include the following:

   logging_inputs

   Defines a list of logging input dictionaries. The type: remote option covers remote inputs from the other logging system over the network. The udp_ports: [ 601 ] option defines a list of UDP port numbers to monitor. The tcp_ports: [ 601 ] option defines a list of TCP port numbers to monitor. If both udp_ports and tcp_ports are set, udp_ports is used and tcp_ports is dropped.

   logging_outputs

   Defines a list of logging output dictionaries. The type: remote_files option makes output store logs to the local files per remote host and program name originated the logs.

   logging_flows

   Defines a list of logging flow dictionaries to specify relationships between logging_inputs and logging_outputs. The inputs: [remote_udp_input, remote_tcp_input] option specifies a list of inputs, from which processing of logs starts. The outputs: [remote_files_output] option specifies a list of outputs, to which the logs are sent.

   The settings specified in the second play of the example playbook include the following:

   logging_inputs

   Defines a list of logging input dictionaries. The type: basics option covers inputs from systemd journal or Unix socket.

   logging_outputs

   Defines a list of logging output dictionaries. The type: forwards option supports sending logs to the remote logging server over the network. The severity: info option refers to log messages of informative importance. The facility: mail option refers to the type of system program that is generating the log message. The target: <host1.example.com> option specifies the hostname of the remote logging server. The udp_port: 601/tcp_port: 601 options define the UDP/TCP ports on which the remote logging server listens.

   logging_flows

   Defines a list of logging flow dictionaries to specify relationships between logging_inputs and logging_outputs. The inputs: [basic_input] option specifies a list of inputs, from which processing of logs starts. The outputs: [forward_output0, forward_output1] option specifies a list of outputs, to which the logs are sent.

   For details about the role variables and more information about rsyslog, see the /usr/share/ansible/roles/rhel-system-roles.logging/README.md file and the rsyslog.conf(5) and syslog(3) manual pages on the control node.

2. Validate the playbook syntax:

   $ ansible-playbook --syntax-check ~/playbook.yml

   Note that this command only validates the syntax and does not protect against a wrong but valid configuration.

3. Run the playbook:

   $ ansible-playbook ~/playbook.yml

Verification

1. On both the client and the server system, test the syntax of the /etc/rsyslog.conf file:

   # rsyslogd -N 1
   rsyslogd: version 8.1911.0-6.el8, config validation run (level 1), master config /etc/rsyslog.conf
   rsyslogd: End of config validation run. Bye.

2. Verify that the client system sends messages to the server:

   1. On the client system, send a test message:

      # logger test

   2. On the server system, view the /var/log/<host2.example.com>/messages log, for example:

      # cat /var/log/<host2.example.com>/messages
      Aug  5 13:48:31 <host2.example.com> root[6778]: test

      Where <host2.example.com> is the host name of the client system. Note that the log contains the user name of the user that entered the logger command, in this case root.