[HN Gopher] Observe a Service; Not a Server
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       Observe a Service; Not a Server
        
       Author : kiyanwang
       Score  : 14 points
       Date   : 2021-08-02 05:44 UTC (17 hours ago)
        
 (HTM) web link (blog.last9.io)
 (TXT) w3m dump (blog.last9.io)
        
       | pmlnr wrote:
       | Right. Do this and you'll never be able to find that single
       | machine that believes it's on a 100mbit line instead of 10G and
       | keep wondering why every X user has a problem.
       | 
       | Monitor both, please.
        
         | imwillofficial wrote:
         | A billion times this. The cattle still need love.
        
         | cotillion wrote:
         | Yes monitor. You really want to find that server which is busy
         | encrypting all that nice data your service needs.
        
         | derefr wrote:
         | The article is talking about "monitoring" in the sense of
         | alerting + stakeholder incident reporting. Things that reach
         | out and tell ops staff / users that the service is having a
         | problem.
         | 
         | You do want to be capturing _metrics_ about your servers --
         | _observability into_ their configuration and behavior -- but
         | capturing that type of data is not precisely the same thing as
         | "monitoring" the server. "Monitoring" usually implies having a
         | defined acceptance threshold on the metric, and triggering some
         | (probably human) response when the metric is in an unacceptable
         | range.
         | 
         | If you don't have either a clear threshold for the metric, or a
         | clear "thing that should happen" when the metric goes out-of-
         | tolerance, then you aren't "monitoring" the metric per se; or
         | at least, you _shouldn 't_ be.
         | 
         | As the article says:
         | 
         | > Here's an example: A disk consuming 100% at 3 AM may or may
         | not be actionable depending on its impact on service KPI. For
         | instance, if it's a logout service and the KPI says 99.999%
         | availability despite a disk failure, It can wait till the
         | morning.
         | 
         | If you have set up alerting for server disks being full, where
         | that alert often _doesn 't_ translate into any problem with
         | your running services, then that alert is a useless/noise
         | alert, that will only serve to make you treat notifications
         | from your alerting infrastructure with less urgency. It's the
         | "check-engine light" of SaaS.
         | 
         | It's fine to have a dashboard that holds all that stuff. But it
         | shouldn't be reaching out and telling you/users about it. You
         | can go look at that dashboard when _investigating_ why the
         | service KPIs you 're alerting on are down.
         | 
         | In your example, the appropriate service KPI to alert on would
         | be "[service] 99th percentile end-to-end response latency."
         | Upon receiving an alert that that number is out-of-tolerance,
         | you'd then start to investigate your individual -- or,
         | hopefully, aggregated! -- server _metrics_ , to see what-if-
         | anything is acting weird.
        
           | nix23 wrote:
           | >"Monitoring" usually implies having a defined acceptance
           | threshold on the metric, and triggering some (probably human)
           | response when the metric is in an unacceptable range.
           | 
           | Like the Smart data on your Hard-drives? The increasingly
           | (over month) thrown away packets of a dying Network card? Or
           | that one Fan that increasingly spins slower then all others?
           | 
           | Look Hard is not different from Software, both need to be
           | Monitored having a close look on "trends" and want to be
           | Maintained.
        
         | nix23 wrote:
         | Full hit! If one think in services, the Hardware is the first
         | service one should observe, just thinking about the running
         | Software ON IT as a service is ridiculous. Good luck
         | "debugging" your performance problems if your Hardware is
         | struggling to keep the Raid up, trowing packets away a hardware
         | level...or hey, running at 600Mzh because the CPU is boiling,
         | two fan's reported errors, hell even fans are services (by
         | providing airflow)
        
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       (page generated 2021-08-02 23:03 UTC)