resolv.conf solved!

files/alertmanager/alertmanager.service

@@ -0,0 +1,21 @@
+[Unit]
+Description=Prometheus alertmanager
+Wants=network-online.target
+After=network-online.target
+
+[Service]
+User=prometheus
+Group=prometheus
+EnvironmentFile=-/etc/sysconfig/alertmanager
+ExecStart=/usr/sbin/alertmanager \
+    --config.file=/etc/alertmanager/alertmanager.yaml \
+    --storage.path=/base/alertmanager \
+    --web.config.file=/etc/prometheus/web-config.yaml
+
+ExecReload=/bin/kill -HUP $MAINPID
+KillMode=process
+Restart=always
+
+[Install]
+WantedBy=multi-user.target
+