Scrape duration using prometheus is increasing continuously until restart

### problem

We are using Prometheus to scrape metrics from the management server.
We see a issue that the scrape_duration_seconds metric for the cloudstack job is increasing in slow pace and after ~7-10 days the scrape duration is longer then the configured interval and we get no more metrics.
First time we saw this just doing a time curl towards the mangement server it took 40-50s for metrics to come back.

### versions

CloudStack 4.22.0.0

### The steps to reproduce the bug

1. Start scraping
2. See the scrape_duration_seconds{job="cloudstack"} increasing daily.

### What to do about it?

1. Restart the management server solves the issue, temporarily

從 CloudStack 管理伺服器的 Prometheus metrics endpoint 開始，透過連續數天對其進行抓取來重現該問題，同時觀察 scrape_duration_seconds{job="cloudstack"}。將 endpoint 回應時間與設定的抓取間隔進行比較；當抓取持續時間不再持續增加，且 metrics 在無需重新啟動管理伺服器的情況下仍然可用時，即表示完成。

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