If so I'll need to figure out a way to pre-initialize the metric which may be difficult since the label values may not be known a priori. 02:00 - create a new chunk for 02:00 - 03:59 time range, 04:00 - create a new chunk for 04:00 - 05:59 time range, 22:00 - create a new chunk for 22:00 - 23:59 time range. 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. Before running the query, create a Pod with the following specification: Before running the query, create a PersistentVolumeClaim with the following specification: This will get stuck in Pending state as we dont have a storageClass called manual" in our cluster. are going to make it The real power of Prometheus comes into the picture when you utilize the alert manager to send notifications when a certain metric breaches a threshold. Managed Service for Prometheus Cloud Monitoring Prometheus # ! Finally getting back to this. Using a query that returns "no data points found" in an expression. Are there tables of wastage rates for different fruit and veg? By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Returns a list of label values for the label in every metric. This article covered a lot of ground. We had a fair share of problems with overloaded Prometheus instances in the past and developed a number of tools that help us deal with them, including custom patches. A time series is an instance of that metric, with a unique combination of all the dimensions (labels), plus a series of timestamp & value pairs - hence the name time series. By default Prometheus will create a chunk per each two hours of wall clock. 1 Like. To make things more complicated you may also hear about samples when reading Prometheus documentation. accelerate any SSH into both servers and run the following commands to install Docker. what error message are you getting to show that theres a problem? Yeah, absent() is probably the way to go. Setting label_limit provides some cardinality protection, but even with just one label name and huge number of values we can see high cardinality. These queries will give you insights into node health, Pod health, cluster resource utilization, etc. or Internet application, If your expression returns anything with labels, it won't match the time series generated by vector(0). https://grafana.com/grafana/dashboards/2129. our free app that makes your Internet faster and safer. Why is there a voltage on my HDMI and coaxial cables? How to tell which packages are held back due to phased updates. *) in region drops below 4. alert also has to fire if there are no (0) containers that match the pattern in region. A simple request for the count (e.g., rio_dashorigin_memsql_request_fail_duration_millis_count) returns no datapoints). At this point, both nodes should be ready. Making statements based on opinion; back them up with references or personal experience. If we add another label that can also have two values then we can now export up to eight time series (2*2*2). We know what a metric, a sample and a time series is. Bulk update symbol size units from mm to map units in rule-based symbology. The TSDB limit patch protects the entire Prometheus from being overloaded by too many time series. However when one of the expressions returns no data points found the result of the entire expression is no data points found.In my case there haven't been any failures so rio_dashorigin_serve_manifest_duration_millis_count{Success="Failed"} returns no data points found.Is there a way to write the query so that a . 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. result of a count() on a query that returns nothing should be 0 ? how have you configured the query which is causing problems? This works fine when there are data points for all queries in the expression. Prometheus and PromQL (Prometheus Query Language) are conceptually very simple, but this means that all the complexity is hidden in the interactions between different elements of the whole metrics pipeline. It's worth to add that if using Grafana you should set 'Connect null values' proeprty to 'always' in order to get rid of blank spaces in the graph. notification_sender-. This is an example of a nested subquery. If we make a single request using the curl command: We should see these time series in our application: But what happens if an evil hacker decides to send a bunch of random requests to our application? Time series scraped from applications are kept in memory. 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 That's the query (Counter metric): sum(increase(check_fail{app="monitor"}[20m])) by (reason). Names and labels tell us what is being observed, while timestamp & value pairs tell us how that observable property changed over time, allowing us to plot graphs using this data. Sign up for a free GitHub account to open an issue and contact its maintainers and the community. Our metric will have a single label that stores the request path. If we have a scrape with sample_limit set to 200 and the application exposes 201 time series, then all except one final time series will be accepted. What is the point of Thrower's Bandolier? @zerthimon You might want to use 'bool' with your comparator the problem you have. 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. Prometheus allows us to measure health & performance over time and, if theres anything wrong with any service, let our team know before it becomes a problem. A time series that was only scraped once is guaranteed to live in Prometheus for one to three hours, depending on the exact time of that scrape. Not the answer you're looking for? Sign up for a free GitHub account to open an issue and contact its maintainers and the community. If we let Prometheus consume more memory than it can physically use then it will crash. By default we allow up to 64 labels on each time series, which is way more than most metrics would use. This is the standard flow with a scrape that doesnt set any sample_limit: With our patch we tell TSDB that its allowed to store up to N time series in total, from all scrapes, at any time. Which in turn will double the memory usage of our Prometheus server. To this end, I set up the query to instant so that the very last data point is returned but, when the query does not return a value - say because the server is down and/or no scraping took place - the stat panel produces no data. To learn more, see our tips on writing great answers. Even i am facing the same issue Please help me on this. By clicking Sign up for GitHub, you agree to our terms of service and (fanout by job name) and instance (fanout by instance of the job), we might There is an open pull request which improves memory usage of labels by storing all labels as a single string. I'm sure there's a proper way to do this, but in the end, I used label_replace to add an arbitrary key-value label to each sub-query that I wished to add to the original values, and then applied an or to each. There is no equivalent functionality in a standard build of Prometheus, if any scrape produces some samples they will be appended to time series inside TSDB, creating new time series if needed. Select the query and do + 0. So, specifically in response to your question: I am facing the same issue - please explain how you configured your data So just calling WithLabelValues() should make a metric appear, but only at its initial value (0 for normal counters and histogram bucket counters, NaN for summary quantiles). Good to know, thanks for the quick response! If this query also returns a positive value, then our cluster has overcommitted the memory. Is there a solutiuon to add special characters from software and how to do it. Simple, clear and working - thanks a lot. I can get the deployments in the dev, uat, and prod environments using this query: So we can see that tenant 1 has 2 deployments in 2 different environments, whereas the other 2 have only one. The process of sending HTTP requests from Prometheus to our application is called scraping. How to filter prometheus query by label value using greater-than, PromQL - Prometheus - query value as label, Why time duration needs double dot for Prometheus but not for Victoria metrics, How do you get out of a corner when plotting yourself into a corner. The actual amount of physical memory needed by Prometheus will usually be higher as a result, since it will include unused (garbage) memory that needs to be freed by Go runtime. PromQL queries the time series data and returns all elements that match the metric name, along with their values for a particular point in time (when the query runs). Better to simply ask under the single best category you think fits and see This is the standard Prometheus flow for a scrape that has the sample_limit option set: The entire scrape either succeeds or fails. count the number of running instances per application like this: This documentation is open-source. Please dont post the same question under multiple topics / subjects. Connect and share knowledge within a single location that is structured and easy to search. So there would be a chunk for: 00:00 - 01:59, 02:00 - 03:59, 04:00 . There is an open pull request on the Prometheus repository. One of the most important layers of protection is a set of patches we maintain on top of Prometheus. The number of times some specific event occurred. What does remote read means in Prometheus? All regular expressions in Prometheus use RE2 syntax. Managing the entire lifecycle of a metric from an engineering perspective is a complex process. instance_memory_usage_bytes: This shows the current memory used. A metric can be anything that you can express as a number, for example: To create metrics inside our application we can use one of many Prometheus client libraries. Why are physically impossible and logically impossible concepts considered separate in terms of probability? Find centralized, trusted content and collaborate around the technologies you use most. what error message are you getting to show that theres a problem? By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Theres no timestamp anywhere actually. @juliusv Thanks for clarifying that. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. 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. In this query, you will find nodes that are intermittently switching between Ready" and NotReady" status continuously. To learn more about our mission to help build a better Internet, start here. Looking to learn more? What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? The Graph tab allows you to graph a query expression over a specified range of time. Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? That way even the most inexperienced engineers can start exporting metrics without constantly wondering Will this cause an incident?. After a chunk was written into a block and removed from memSeries we might end up with an instance of memSeries that has no chunks. This would happen if any time series was no longer being exposed by any application and therefore there was no scrape that would try to append more samples to it.