Allow GitLab instance to start when InfluxDB hostname cannot be resolved

Closes #24438

changelogs/unreleased/adam-influxdb-hostname.yml

+---
+title: Allow GitLab instance to start when InfluxDB hostname cannot be resolved
+merge_request: 11356
+author:

lib/gitlab/metrics.rb

@@ -49,6 +49,9 @@ module Gitlab
           end
         end
       end
+    rescue Errno::EADDRNOTAVAIL, SocketError => ex
+      Gitlab::EnvironmentLogger.error('Cannot resolve InfluxDB address. GitLab Performance Monitoring will not work.')
+      Gitlab::EnvironmentLogger.error(ex)
     end
     def self.prepare_metrics(metrics)