檢視 Prometheus 的原始碼

'''Prometheus'''是一個[[TSDB]]。

== 概要 ==

Prometheus本身是一個TSDB（Time series database），會主動到目標機器上蒐集資料後寫入資料庫，另外Prometheus可以設定警示條件送進Alertmanager，由Alertmanager送到外部服務通知（像是[[Slack]]，或是[[PagerDuty]]）。

== 安裝 ==

[[Ubuntu]] 20.04系統內的Prometheus太舊（2.15），加上沒有適合的PPA可以用，這邊使用官方的binary安裝：

<syntaxhighlight lang="bash">
export PROMETHEUS_VERSION=2.45.0; cd /tmp; wget https://github.com/prometheus/prometheus/releases/download/v${PROMETHEUS_VERSION}/prometheus-${PROMETHEUS_VERSION}.linux-amd64.tar.gz; tar xvf prometheus-${PROMETHEUS_VERSION}.linux-amd64.tar.gz; cd prometheus-${PROMETHEUS_VERSION}.linux-amd64; sudo cp -f prometheus promtool /usr/bin; sudo mkdir /etc/prometheus; sudo cp prometheus.yml /etc/prometheus/; sudo cp -R consoles/ console_libraries/ /etc/prometheus/; sudo useradd -r -U prometheus; sudo mkdir /var/lib/prometheus; sudo chown prometheus:prometheus /var/lib/prometheus; echo -e "[Unit]\nDescription=Prometheus Time Series Collection and Processing Server\nWants=network-online.target\nAfter=network-online.target\n\n[Service]\nUser=prometheus\nGroup=prometheus\nType=simple\nExecStart=/usr/bin/prometheus --config.file /etc/prometheus/prometheus.yml --storage.tsdb.path /var/lib/prometheus/ --web.console.templates=/etc/prometheus/consoles --web.console.libraries=/etc/prometheus/console_libraries\n\n[Install]\nWantedBy=multi-user.target" | sudo tee /lib/systemd/system/prometheus.service; sudo systemctl daemon-reload; sudo systemctl enable prometheus; sudo service prometheus start
</syntaxhighlight>

另外一起裝Alertmanager：

<syntaxhighlight lang="bash">
export ALERTMANAGER_VERSION=0.25.0; cd /tmp; wget https://github.com/prometheus/alertmanager/releases/download/v${ALERTMANAGER_VERSION}/alertmanager-${ALERTMANAGER_VERSION}.linux-amd64.tar.gz; tar xvf alertmanager-${ALERTMANAGER_VERSION}.linux-amd64.tar.gz; cd alertmanager-${ALERTMANAGER_VERSION}.linux-amd64; sudo cp -f alertmanager amtool /usr/bin; sudo mkdir /etc/amtool /var/lib/alertmanager; sudo chown prometheus:prometheus /var/lib/alertmanager; sudo cp alertmanager.yml /etc/amtool; echo -e "[Unit]\nDescription=Prometheus Alertmanager\nWants=network-online.target\nAfter=network-online.target\n\n[Service]\nUser=prometheus\nGroup=prometheus\nType=simple\nExecStart=/usr/bin/alertmanager --config.file /etc/amtool/alertmanager.yml --storage.path /var/lib/alertmanager\n\n[Install]\nWantedBy=multi-user.target" | sudo tee /lib/systemd/system/alertmanager.service; sudo systemctl daemon-reload; sudo systemctl enable alertmanager; sudo service alertmanager start
</syntaxhighlight>

在[[Ubuntu]]內有內建blackbox-exporter，可以拿來監控HTTP或是SSH：

<syntaxhighlight lang="bash">
sudo apt install -y prometheus-blackbox-exporter; sudo apt clean
</syntaxhighlight>

== 設定 ==

要注意官方安裝檔內的<code>prometheus.yml</code>中<code>scrape_interval</code>與<code>evaluation_interval</code>預設是<code>15s</code>（但不設定時預設是<code>1m</code>），正常情況下<code>5m</code>應該是夠用，可以考慮指定<code>5m</code>降低頻率。

== Query ==

基本上一定會有的：

<syntaxhighlight lang="text">
node_cpu_seconds_total
</syntaxhighlight>

== 相關連結 ==

* [[Grafana]]

== 外部連結 ==

* {{Official|https://prometheus.io/}} {{en}}

[[Category:軟體]]