Since prometheus is a pulled based metric tracker.
Now lets say I have a simple service and I Need to expose metrics for Prometheus to scrape, Now I do that with one of the clients of the language, configured Prometheus to poll at a frequency of 15secs this API of metrics, Now I have a count metric, Prometheus server at time instance at time t saw count x, At time t+15 sees count y
Now becuase of the scrap interval(pull model) I don't have any idea wether the increase of count x to y had a steady slope or a Spike of requests came in at t+10
Got an answer at the prometheus group https://groups.google.com/forum/#!topic/prometheus-users/8--nJRokE8Y
Related
If I send a gauge to Prometheus then the payload has a timestamp and a value like:
metric_name {label="value"} 2.0 16239938546837
If I query it on Prometheus I can see a continous line. Without sending a payload for the same metric the line stops. Sending the same metric after some minutes I get another continous line, but it is not connected with the old line.
Is this fixed in Prometheus how long a timeseries last without getting an update?
I think the first answer by Marc is in a different context.
Any timeseries in prometheus goes stale in 5m by default if the collection stops - https://www.robustperception.io/staleness-and-promql. In other words, the line stops on graph (or grafana).
So if you resume the metrics collection again within 5 minutes, then it will connect the line by default. But if there is no collection for more than 5 minutes then it will show a disconnect on the graph. You can tweak that on Grafana to ignore drops but that not ideal in some cases as you do want to see when the collection stopped instead of giving the false impression that there was continuous collection. Alternatively, you can avoid the disconnect using some functions like avg_over_time(metric_name[10m]) as needed.
There is two questions here :
1. How long does prometheus keeps the data ?
This depends on the configuration you have for your storage. By default, on local storage, prometheus have a retention of 15days. You can find out more in the documentation. You can also change this value with this option : --storage.tsdb.retention.time
2. When will I have a "hole" in my graph ?
The line you see on a graph is made by joining each point from each scrape. Those scrape are done regularly based on the scrape_interval value you have in your scrape_config. So basically, if you have no data during one scrape, then you'll have a hole.
So there is no definitive answer, this depends essentially on your scrape_interval.
Note that if you're using a function that evaluate metrics for a certain amount of time, then missing one scrape will not alter your graph. For example, using a rate[5m] will not alter your graph if you scrape every 1m (as you'll have 4 other samples to do the rate).
How can I collect network bandwidth on the network interface for a month?Is it possible to get data by zabbix tools? One of the main problems is to set up period for monitoring. I create calculated item that get traffic for a minute and I try to sum it by function "sum(total.traffic[{#IFNAME}],30d)", but it returns me value for the last 30 days. How can I set up some period that will return sum of values from beginning of month to nowadays?
The easiest solution is that you use vnstat
Here you have everything
monthly Bandwidth in Zabbix
Let's say I have some software running on a VM that is emitting two metrics that are fed through Telegraf to be written into InfluxDB. Let's say the metric are no. successfully handled HTTP requests (S), and no. of failed HTTP requests (F), on that VM. However, I might configure three such VMs each emitting those 2 metrics.
Now, if I would like to have a computed metric which is the sum of S from each VM, and sum of F from each VM, and store as new metrics, at various instants of time. Is this something that can be achieved using Telegraf ? Or is there a better, more efficient, more elegant way ?
Kindly note that my knowledge of Telegraf and InfluxDB are theoretical, as I've recently started reading up about them, so I have not actually tried any of the above, yet.
This isn't something telegraf would be responsible for.
With Influx 1.x, you'd use a TICKScript or Continuous Queries to calculate the sum and inject the new sampled value.
Roughly, this would look like:
CREATE CONTINUOUS QUERY "sum_sample_daily" ON "database"
BEGIN
SELECT sum("*") INTO "daily_measurement" FROM "measurement" GROUP BY time(1d)
END
CQ docs
Is it possible calculate operation duration in prometheus when the data is collected as start time (epoch) and end time (epoch) that would be grouped by some form of a transaction trace?
Once duration is known, the data can then be used to provide a prometheus Apdex.
Use case:
API initiates fires (and essentially forgets) a start operation request
Multiple distributed (message based) processes take place
Final message fires and indicates the end of the operation
Prometheus is a metrics-based system, not a tracing system. The most you can do is track a summary of how long all your requests are taking using the Summary or Histogram metric types.
I'm using Prometheus' Summary metric to collect the latency of an API call. Instead of making an actual API call, I'm simply calling Thread.sleep(1000) to simulate a 1 second api-call latency value -- this makes the Summary hold a value of .01 (for 1 second of latency). But if, for example, I invoke Thread.sleep(1000) twice in the same minute, the Summary metric ends up with a value of .02 (for 2 seconds of latency), instead of two individual instances of .01 latency that just happened to occur within the same minute. My problem is the Prometheus query. The Prometheus query I am currently using is: rate(my_custom_summary_sum[1m]).
What should my Prometheus query be, such that I can see the latency of each individual Thread.sleep(1000) invocation. As of right now, the Summary metric collects and displays the total latency sum per minute. How can I display the latency of each individual call to Thread.sleep(1000) (i.e. the API request)?
private static final Summary mySummary = Summary.build()
.name("my_custom_summary")
.help("This is a custom summary that keeps track of latency")
.register();
Summary.Timer requestTimer = mySummary.startTimer(); //starting timer for mySummary 'Summary' metric
Thread.sleep(1000); //sleep for one second
requestTimer.observeDuration(); //record the time elapsed
This is the graph that results from this query:
Prometheus graph
Prometheus is a metrics-based monitoring system, it cares about overall performance and behaviour - not individual requests.
What you are looking for is a logs-based system, such as Graylog or the ELK stack.