prometheus query return 0 if no data prometheus query return 0 if no data

what does the Query Inspector show for the query you have a problem with? Prometheus - exclude 0 values from query result, How Intuit democratizes AI development across teams through reusability. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Redoing the align environment with a specific formatting. We also limit the length of label names and values to 128 and 512 characters, which again is more than enough for the vast majority of scrapes. This works well if errors that need to be handled are generic, for example Permission Denied: But if the error string contains some task specific information, for example the name of the file that our application didnt have access to, or a TCP connection error, then we might easily end up with high cardinality metrics this way: Once scraped all those time series will stay in memory for a minimum of one hour. I can't work out how to add the alerts to the deployments whilst retaining the deployments for which there were no alerts returned: If I use sum with or, then I get this, depending on the order of the arguments to or: If I reverse the order of the parameters to or, I get what I am after: But I'm stuck now if I want to do something like apply a weight to alerts of a different severity level, e.g. Returns a list of label values for the label in every metric. This process helps to reduce disk usage since each block has an index taking a good chunk of disk space. We know that each time series will be kept in memory. If this query also returns a positive value, then our cluster has overcommitted the memory. Once configured, your instances should be ready for access. Lets create a demo Kubernetes cluster and set up Prometheus to monitor it. How to follow the signal when reading the schematic? Once we do that we need to pass label values (in the same order as label names were specified) when incrementing our counter to pass this extra information. Of course there are many types of queries you can write, and other useful queries are freely available. Simple, clear and working - thanks a lot. So there would be a chunk for: 00:00 - 01:59, 02:00 - 03:59, 04:00 - 05:59, , 22:00 - 23:59. You saw how PromQL basic expressions can return important metrics, which can be further processed with operators and functions. help customers build Then imported a dashboard from " 1 Node Exporter for Prometheus Dashboard EN 20201010 | Grafana Labs ".Below is my Dashboard which is showing empty results.So kindly check and suggest. Chunks will consume more memory as they slowly fill with more samples, after each scrape, and so the memory usage here will follow a cycle - we start with low memory usage when the first sample is appended, then memory usage slowly goes up until a new chunk is created and we start again. Is it possible to create a concave light? How is Jesus " " (Luke 1:32 NAS28) different from a prophet (, Luke 1:76 NAS28)? Our patched logic will then check if the sample were about to append belongs to a time series thats already stored inside TSDB or is it a new time series that needs to be created. Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? Run the following commands on the master node to set up Prometheus on the Kubernetes cluster: Next, run this command on the master node to check the Pods status: Once all the Pods are up and running, you can access the Prometheus console using kubernetes port forwarding. Doubling the cube, field extensions and minimal polynoms. Returns a list of label names. One Head Chunk - containing up to two hours of the last two hour wall clock slot. To avoid this its in general best to never accept label values from untrusted sources. The next layer of protection is checks that run in CI (Continuous Integration) when someone makes a pull request to add new or modify existing scrape configuration for their application. Both of the representations below are different ways of exporting the same time series: Since everything is a label Prometheus can simply hash all labels using sha256 or any other algorithm to come up with a single ID that is unique for each time series. You can query Prometheus metrics directly with its own query language: PromQL. but viewed in the tabular ("Console") view of the expression browser. Especially when dealing with big applications maintained in part by multiple different teams, each exporting some metrics from their part of the stack. Bulk update symbol size units from mm to map units in rule-based symbology. Samples are stored inside chunks using "varbit" encoding which is a lossless compression scheme optimized for time series data. Our metrics are exposed as a HTTP response. He has a Bachelor of Technology in Computer Science & Engineering from SRMS. If so it seems like this will skew the results of the query (e.g., quantiles). Its least efficient when it scrapes a time series just once and never again - doing so comes with a significant memory usage overhead when compared to the amount of information stored using that memory. However when one of the expressions returns no data points found the result of the entire expression is no data points found. Have a question about this project? Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? The Head Chunk is never memory-mapped, its always stored in memory. want to sum over the rate of all instances, so we get fewer output time series, All regular expressions in Prometheus use RE2 syntax. Here at Labyrinth Labs, we put great emphasis on monitoring. Return all time series with the metric http_requests_total: Return all time series with the metric http_requests_total and the given This is one argument for not overusing labels, but often it cannot be avoided. @zerthimon You might want to use 'bool' with your comparator What is the point of Thrower's Bandolier? VictoriaMetrics handles rate () function in the common sense way I described earlier! @rich-youngkin Yes, the general problem is non-existent series. Theres only one chunk that we can append to, its called the Head Chunk. Perhaps I misunderstood, but it looks like any defined metrics that hasn't yet recorded any values can be used in a larger expression. The region and polygon don't match. Vinayak is an experienced cloud consultant with a knack of automation, currently working with Cognizant Singapore. Sign up and get Kubernetes tips delivered straight to your inbox. Its also worth mentioning that without our TSDB total limit patch we could keep adding new scrapes to Prometheus and that alone could lead to exhausting all available capacity, even if each scrape had sample_limit set and scraped fewer time series than this limit allows. Prometheus's query language supports basic logical and arithmetic operators. You set up a Kubernetes cluster, installed Prometheus on it ,and ran some queries to check the clusters health. At this point we should know a few things about Prometheus: With all of that in mind we can now see the problem - a metric with high cardinality, especially one with label values that come from the outside world, can easily create a huge number of time series in a very short time, causing cardinality explosion. 11 Queries | Kubernetes Metric Data with PromQL, wide variety of applications, infrastructure, APIs, databases, and other sources. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Well be executing kubectl commands on the master node only. Is it a bug? I'm not sure what you mean by exposing a metric. This helps Prometheus query data faster since all it needs to do is first locate the memSeries instance with labels matching our query and then find the chunks responsible for time range of the query. There's also count_scalar(), Each Prometheus is scraping a few hundred different applications, each running on a few hundred servers. scheduler exposing these metrics about the instances it runs): The same expression, but summed by application, could be written like this: If the same fictional cluster scheduler exposed CPU usage metrics like the I don't know how you tried to apply the comparison operators, but if I use this very similar query: I get a result of zero for all jobs that have not restarted over the past day and a non-zero result for jobs that have had instances restart. Is a PhD visitor considered as a visiting scholar? However, if i create a new panel manually with a basic commands then i can see the data on the dashboard. our free app that makes your Internet faster and safer. positions. By clicking Sign up for GitHub, you agree to our terms of service and Instead we count time series as we append them to TSDB. The Prometheus data source plugin provides the following functions you can use in the Query input field. Lets say we have an application which we want to instrument, which means add some observable properties in the form of metrics that Prometheus can read from our application. But you cant keep everything in memory forever, even with memory-mapping parts of data. How do I align things in the following tabular environment? Why are trials on "Law & Order" in the New York Supreme Court? The main motivation seems to be that dealing with partially scraped metrics is difficult and youre better off treating failed scrapes as incidents. If we configure a sample_limit of 100 and our metrics response contains 101 samples, then Prometheus wont scrape anything at all. gabrigrec September 8, 2021, 8:12am #8. Setting label_limit provides some cardinality protection, but even with just one label name and huge number of values we can see high cardinality. count(ALERTS) or (1-absent(ALERTS)), Alternatively, count(ALERTS) or vector(0). There is an open pull request which improves memory usage of labels by storing all labels as a single string. It would be easier if we could do this in the original query though. Find centralized, trusted content and collaborate around the technologies you use most. No error message, it is just not showing the data while using the JSON file from that website. Is what you did above (failures.WithLabelValues) an example of "exposing"? Prometheus has gained a lot of market traction over the years, and when combined with other open-source tools like Grafana, it provides a robust monitoring solution. Explanation: Prometheus uses label matching in expressions. t]. https://grafana.com/grafana/dashboards/2129. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2, Show or hide query result depending on variable value in Grafana, Understanding the CPU Busy Prometheus query, Group Label value prefixes by Delimiter in Prometheus, Why time duration needs double dot for Prometheus but not for Victoria metrics, Using a Grafana Histogram with Prometheus Buckets. With this simple code Prometheus client library will create a single metric. Not the answer you're looking for? If you're looking for a See this article for details. Improving your monitoring setup by integrating Cloudflares analytics data into Prometheus and Grafana Pint is a tool we developed to validate our Prometheus alerting rules and ensure they are always working website *) in region drops below 4. On Thu, Dec 15, 2016 at 6:24 PM, Lior Goikhburg ***@***. Prometheus Authors 2014-2023 | Documentation Distributed under CC-BY-4.0. What sort of strategies would a medieval military use against a fantasy giant? This means that Prometheus must check if theres already a time series with identical name and exact same set of labels present. Even i am facing the same issue Please help me on this. I know prometheus has comparison operators but I wasn't able to apply them. A common class of mistakes is to have an error label on your metrics and pass raw error objects as values. list, which does not convey images, so screenshots etc. to your account, What did you do? Now comes the fun stuff. Does a summoned creature play immediately after being summoned by a ready action? In the same blog post we also mention one of the tools we use to help our engineers write valid Prometheus alerting rules. A sample is something in between metric and time series - its a time series value for a specific timestamp. First rule will tell Prometheus to calculate per second rate of all requests and sum it across all instances of our server. Not the answer you're looking for? Having good internal documentation that covers all of the basics specific for our environment and most common tasks is very important. In our example case its a Counter class object. Then you must configure Prometheus scrapes in the correct way and deploy that to the right Prometheus server. Has 90% of ice around Antarctica disappeared in less than a decade? But before doing that it needs to first check which of the samples belong to the time series that are already present inside TSDB and which are for completely new time series. In the screenshot below, you can see that I added two queries, A and B, but only . Going back to our time series - at this point Prometheus either creates a new memSeries instance or uses already existing memSeries. What is the point of Thrower's Bandolier? Prometheus is an open-source monitoring and alerting software that can collect metrics from different infrastructure and applications. VictoriaMetrics has other advantages compared to Prometheus, ranging from massively parallel operation for scalability, better performance, and better data compression, though what we focus on for this blog post is a rate () function handling. Asking for help, clarification, or responding to other answers. Chunks that are a few hours old are written to disk and removed from memory. This thread has been automatically locked since there has not been any recent activity after it was closed. to get notified when one of them is not mounted anymore. ncdu: What's going on with this second size column? What this means is that a single metric will create one or more time series. This allows Prometheus to scrape and store thousands of samples per second, our biggest instances are appending 550k samples per second, while also allowing us to query all the metrics simultaneously. Add field from calculation Binary operation. By default we allow up to 64 labels on each time series, which is way more than most metrics would use. You can run a variety of PromQL queries to pull interesting and actionable metrics from your Kubernetes cluster. Now, lets install Kubernetes on the master node using kubeadm. This holds true for a lot of labels that we see are being used by engineers. vishnur5217 May 31, 2020, 3:44am 1.