If the time series doesnt exist yet and our append would create it (a new memSeries instance would be created) then we skip this sample. rate (http_requests_total [5m]) [30m:1m] This patchset consists of two main elements. Is a PhD visitor considered as a visiting scholar? Even Prometheus' own client libraries had bugs that could expose you to problems like this. The main motivation seems to be that dealing with partially scraped metrics is difficult and youre better off treating failed scrapes as incidents. There is a single time series for each unique combination of metrics labels. Thanks for contributing an answer to Stack Overflow! instance_memory_usage_bytes: This shows the current memory used. Chunks that are a few hours old are written to disk and removed from memory. If a sample lacks any explicit timestamp then it means that the sample represents the most recent value - its the current value of a given time series, and the timestamp is simply the time you make your observation at. If we let Prometheus consume more memory than it can physically use then it will crash. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. group by returns a value of 1, so we subtract 1 to get 0 for each deployment and I now wish to add to this the number of alerts that are applicable to each deployment. or Internet application, A simple request for the count (e.g., rio_dashorigin_memsql_request_fail_duration_millis_count) returns no datapoints). Just add offset to the query. On the worker node, run the kubeadm joining command shown in the last step. You can query Prometheus metrics directly with its own query language: PromQL. Using the Prometheus data source - Amazon Managed Grafana which outputs 0 for an empty input vector, but that outputs a scalar We know that time series will stay in memory for a while, even if they were scraped only once. The below posts may be helpful for you to learn more about Kubernetes and our company. Our metrics are exposed as a HTTP response. Hmmm, upon further reflection, I'm wondering if this will throw the metrics off. After running the query, a table will show the current value of each result time series (one table row per output series). @zerthimon The following expr works for me Cadvisors on every server provide container names. Lets adjust the example code to do this. entire corporate networks, It might seem simple on the surface, after all you just need to stop yourself from creating too many metrics, adding too many labels or setting label values from untrusted sources. Please dont post the same question under multiple topics / subjects. But you cant keep everything in memory forever, even with memory-mapping parts of data. Those limits are there to catch accidents and also to make sure that if any application is exporting a high number of time series (more than 200) the team responsible for it knows about it. Lets create a demo Kubernetes cluster and set up Prometheus to monitor it. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. In the following steps, you will create a two-node Kubernetes cluster (one master and one worker) in AWS. In this article, you will learn some useful PromQL queries to monitor the performance of Kubernetes-based systems. Asking for help, clarification, or responding to other answers. In both nodes, edit the /etc/hosts file to add the private IP of the nodes. What is the point of Thrower's Bandolier? - I am using this in windows 10 for testing, which Operating System (and version) are you running it under? This is the last line of defense for us that avoids the risk of the Prometheus server crashing due to lack of memory. Please help improve it by filing issues or pull requests. Sign up for a free GitHub account to open an issue and contact its maintainers and the community. I am interested in creating a summary of each deployment, where that summary is based on the number of alerts that are present for each deployment. These will give you an overall idea about a clusters health. Another reason is that trying to stay on top of your usage can be a challenging task. Why is there a voltage on my HDMI and coaxial cables? Of course there are many types of queries you can write, and other useful queries are freely available. Run the following commands in both nodes to install kubelet, kubeadm, and kubectl. Operating such a large Prometheus deployment doesnt come without challenges. Or maybe we want to know if it was a cold drink or a hot one? "no data". With our example metric we know how many mugs were consumed, but what if we also want to know what kind of beverage it was? All rights reserved. Managed Service for Prometheus Cloud Monitoring Prometheus # ! count(ALERTS) or (1-absent(ALERTS)), Alternatively, count(ALERTS) or vector(0). Returns a list of label names. binary operators to them and elements on both sides with the same label set I've been using comparison operators in Grafana for a long while. Im new at Grafan and Prometheus. We protect How do you get out of a corner when plotting yourself into a corner, Partner is not responding when their writing is needed in European project application. Connect and share knowledge within a single location that is structured and easy to search. 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. What this means is that a single metric will create one or more time series. All regular expressions in Prometheus use RE2 syntax. I'm still out of ideas here. Internet-scale applications efficiently, by (geo_region) < bool 4 To learn more about our mission to help build a better Internet, start here. count(container_last_seen{name="container_that_doesn't_exist"}), What did you see instead? As we mentioned before a time series is generated from metrics. What happens when somebody wants to export more time series or use longer labels? This is one argument for not overusing labels, but often it cannot be avoided. Have a question about this project? We know what a metric, a sample and a time series is. With 1,000 random requests we would end up with 1,000 time series in Prometheus. It saves these metrics as time-series data, which is used to create visualizations and alerts for IT teams. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Find centralized, trusted content and collaborate around the technologies you use most. Good to know, thanks for the quick response! This pod wont be able to run because we dont have a node that has the label disktype: ssd. @zerthimon You might want to use 'bool' with your comparator This makes a bit more sense with your explanation. accelerate any While the sample_limit patch stops individual scrapes from using too much Prometheus capacity, which could lead to creating too many time series in total and exhausting total Prometheus capacity (enforced by the first patch), which would in turn affect all other scrapes since some new time series would have to be ignored. To avoid this its in general best to never accept label values from untrusted sources. If we try to append a sample with a timestamp higher than the maximum allowed time for current Head Chunk, then TSDB will create a new Head Chunk and calculate a new maximum time for it based on the rate of appends. job and handler labels: Return a whole range of time (in this case 5 minutes up to the query time) Operators | Prometheus In reality though this is as simple as trying to ensure your application doesnt use too many resources, like CPU or memory - you can achieve this by simply allocating less memory and doing fewer computations. 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. The speed at which a vehicle is traveling. That map uses labels hashes as keys and a structure called memSeries as values. 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. I'm displaying Prometheus query on a Grafana table. So, specifically in response to your question: I am facing the same issue - please explain how you configured your data Please see data model and exposition format pages for more details. prometheus promql Share Follow edited Nov 12, 2020 at 12:27 Is there a single-word adjective for "having exceptionally strong moral principles"? You signed in with another tab or window. This process is also aligned with the wall clock but shifted by one hour. Our CI would check that all Prometheus servers have spare capacity for at least 15,000 time series before the pull request is allowed to be merged. In addition to that in most cases we dont see all possible label values at the same time, its usually a small subset of all possible combinations. 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. Thanks, By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. To set up Prometheus to monitor app metrics: Download and install Prometheus. Asking for help, clarification, or responding to other answers. Prometheus is an open-source monitoring and alerting software that can collect metrics from different infrastructure and applications. Why are trials on "Law & Order" in the New York Supreme Court? However, the queries you will see here are a baseline" audit. windows. Going back to our time series - at this point Prometheus either creates a new memSeries instance or uses already existing memSeries. The problem is that the table is also showing reasons that happened 0 times in the time frame and I don't want to display them. If I now tack on a != 0 to the end of it, all zero values are filtered out: Thanks for contributing an answer to Stack Overflow! The thing with a metric vector (a metric which has dimensions) is that only the series for it actually get exposed on /metrics which have been explicitly initialized. Although, sometimes the values for project_id doesn't exist, but still end up showing up as one. This means that looking at how many time series an application could potentially export, and how many it actually exports, gives us two completely different numbers, which makes capacity planning a lot harder. Prometheus provides a functional query language called PromQL (Prometheus Query Language) that lets the user select and aggregate time series data in real time. How is Jesus " " (Luke 1:32 NAS28) different from a prophet (, Luke 1:76 NAS28)? In our example we have two labels, content and temperature, and both of them can have two different values. One Head Chunk - containing up to two hours of the last two hour wall clock slot. What sort of strategies would a medieval military use against a fantasy giant? or something like that. The way labels are stored internally by Prometheus also matters, but thats something the user has no control over. Internally time series names are just another label called __name__, so there is no practical distinction between name and labels. If both the nodes are running fine, you shouldnt get any result for this query. It enables us to enforce a hard limit on the number of time series we can scrape from each application instance. This gives us confidence that we wont overload any Prometheus server after applying changes. source, what your query is, what the query inspector shows, and any other Prometheus query check if value exist. 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. In general, having more labels on your metrics allows you to gain more insight, and so the more complicated the application you're trying to monitor, the more need for extra labels. This had the effect of merging the series without overwriting any values. want to sum over the rate of all instances, so we get fewer output time series, Managed Service for Prometheus https://goo.gle/3ZgeGxv Having better insight into Prometheus internals allows us to maintain a fast and reliable observability platform without too much red tape, and the tooling weve developed around it, some of which is open sourced, helps our engineers avoid most common pitfalls and deploy with confidence. which Operating System (and version) are you running it under? 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. I have a query that gets a pipeline builds and its divided by the number of change request open in a 1 month window, which gives a percentage. For example, if someone wants to modify sample_limit, lets say by changing existing limit of 500 to 2,000, for a scrape with 10 targets, thats an increase of 1,500 per target, with 10 targets thats 10*1,500=15,000 extra time series that might be scraped. TSDB will try to estimate when a given chunk will reach 120 samples and it will set the maximum allowed time for current Head Chunk accordingly. For a list of trademarks of The Linux Foundation, please see our Trademark Usage page. Examples Object, url:api/datasources/proxy/2/api/v1/query_range?query=wmi_logical_disk_free_bytes%7Binstance%3D~%22%22%2C%20volume%20!~%22HarddiskVolume.%2B%22%7D&start=1593750660&end=1593761460&step=20&timeout=60s, Powered by Discourse, best viewed with JavaScript enabled, 1 Node Exporter for Prometheus Dashboard EN 20201010 | Grafana Labs, https://grafana.com/grafana/dashboards/2129. vishnur5217 May 31, 2020, 3:44am 1. 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). Each chunk represents a series of samples for a specific time range. To get a better understanding of the impact of a short lived time series on memory usage lets take a look at another example. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, Simple succinct answer. Prometheus Authors 2014-2023 | Documentation Distributed under CC-BY-4.0. This would inflate Prometheus memory usage, which can cause Prometheus server to crash, if it uses all available physical memory. Connect and share knowledge within a single location that is structured and easy to search. Has 90% of ice around Antarctica disappeared in less than a decade? This is in contrast to a metric without any dimensions, which always gets exposed as exactly one present series and is initialized to 0. 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. Being able to answer How do I X? yourself without having to wait for a subject matter expert allows everyone to be more productive and move faster, while also avoiding Prometheus experts from answering the same questions over and over again. There is a maximum of 120 samples each chunk can hold. Is a PhD visitor considered as a visiting scholar? For that reason we do tolerate some percentage of short lived time series even if they are not a perfect fit for Prometheus and cost us more memory. an EC2 regions with application servers running docker containers. There is an open pull request which improves memory usage of labels by storing all labels as a single string. Visit 1.1.1.1 from any device to get started with The more labels we have or the more distinct values they can have the more time series as a result. 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. Labels are stored once per each memSeries instance. To make things more complicated you may also hear about samples when reading Prometheus documentation.