Prometheus : Add Monitoring Target2020/07/17

	Add Monitoring Target Nodes.
[1]	Install [node-exporter] package on the Node you'd like to add that includes features to get metric data of general resource on the System like CPU or Memory usage.

[root@node01 ~]# cat > /etc/yum.repos.d/prometheus.repo <<'EOF' 
[prometheus]
name=prometheus
baseurl=https://packagecloud.io/prometheus-rpm/release/el/$releasever/$basearch
repo_gpgcheck=1
enabled=1
gpgkey=https://packagecloud.io/prometheus-rpm/release/gpgkey
       https://raw.githubusercontent.com/lest/prometheus-rpm/master/RPM-GPG-KEY-prometheus-rpm
gpgcheck=1
metadata_expire=300
EOF

[root@node01 ~]#

dnf -y install node_exporter

[root@node01 ~]#

systemctl enable --now node_exporter

[2]	If Firewalld is running, allow ports.

[root@node01 ~]#

firewall-cmd --add-port=9100/tcp --permanent

success
[root@node01 ~]#

firewall-cmd --reload

success

[3]	Add setting on Prometheus Server Configuration.

[root@dlp ~]#

vi /etc/prometheus/prometheus.yml

  # line 33: add new Host to [targets] line
    - job_name: node
    static_configs:
      - targets: ['localhost:9100', 'node01.srv.world:9100']

  # alternatively, if you'd like to add to another group,
  # add [job_name] section like follows
  # any name is OK for [job_name]
  - job_name: Hiroshima
    static_configs:
      - targets: ['node01.srv.world:9100']

[root@dlp ~]#

systemctl restart prometheus

[4]	Access to the Prometheus Web UI and click [Status] - [Targets] to verify new nodes are listed.

[5]	To input query directly, it's possbile to display specific Job or Node. The example below shows a Job for [node_load5]. ⇒ node_load5{job="Hirosima"}

[6]	The example below shows a Node for [node_procs_running]. ⇒ node_procs_running{instance=~"node01.*"}

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