An operator needs to query the current, un-extrapolated rate of increase per second over the last 5 minutes for a counter metric named http_requests_total. Which function should they use?
An engineer needs to determine the total absolute increase in disk space consumed over the last 3 hours using a gauge metric node_disk_bytes_used. Which function is appropriate?
You are joining an instant vector of application versions with an instant vector of metrics using a many-to-one relationship. The application version vector has more labels than the metric vector. Which keyword must be appended to the matching modifier to include labels from the 'many' side?
An operator writes a query to calculate error percentage: sum(rate(errors[5m])) / sum(rate(total[5m])) * 100. What happens if the denominator evaluates to zero or has no matching time series?
You are joining an instant vector of application metrics with a static configuration instant vector containing target metadata using 'on(instance) group_right'. What does the 'group_right' modifier achieve?
You need to calculate the 99th percentile of request latency across all instances using a Prometheus histogram metric 'http_request_duration_seconds_bucket'. Which function and setup is correct?
You want to aggregate total memory usage by 'job' using the 'node_memory_Usage_bytes' metric, while keeping the 'instance' label in the output. Which aggregation clause should you use?
You need to calculate the ratio of successful HTTP requests (status 200) to total HTTP requests. Both metrics are counters named 'http_requests_total'. How do you construct this query to ensure proper label matching between status='200' and total requests?
When calculating the 95th percentile from a histogram, why is histogram_quantile(0.95, sum(rate(http_duration_seconds_bucket[5m])) by (le)) the recommended pattern?
You have two metrics: 'up' (a gauge) and 'process_cpu_seconds_total' (a counter). You want to filter 'process_cpu_seconds_total' by instances where 'up == 1'. Which join modifier is required?
An administrator wants to aggregate CPU usage across all nodes, keeping the instance label while summing the values. Which aggregation clause should be used?
When performing a vector-to-vector binary operation between two instant vectors of different label sets, which modifier allows matching on a subset of common labels?
You need to calculate the 99th percentile HTTP request latency from a Prometheus histogram named http_request_duration_seconds. Which function is correct?
A Prometheus alert expression uses rate(http_requests_total[5m]) > 10. During a service restart, counter resets occur. How does the rate() function account for these counter resets?
You need to calculate the per-second rate of increase of http_requests_total over a 1-minute window. Why is using a 1-minute range window generally discouraged in production?
You need to perform a binary operation between two vectors where the left vector has labels {job="api", instance="a"} and the right vector has labels {job="api"}. You want to match them using the job label while retaining the instance label from the left side. Which modifier configuration is correct?
You are troubleshooting a query and notice that label_replace is being used. What is the primary function of label_replace(v, dst_label, replacement, src_label, regex)?
A Prometheus administrator wants to query the current value of the metric 'http_requests_total'. Which of the following PromQL expressions should be used?
You are monitoring a counter metric 'errors_total' and need to calculate the total number of errors that occurred over the last 1 hour. Which function is most appropriate?
A Prometheus selector includes a negative regex match for environment names: 'environment!="staging"'. Which selector operator achieves this using regular expressions instead of exact matching?
When writing a PromQL query involving a vector and a scalar, such as 'node_memory_free_bytes / (1024 * 1024)', how does Prometheus handle label matching?
You are joining two vectors where the left vector has labels {job="api", instance="host1"} and the right vector has labels {job="api", region="us-east"}. You use the query 'vector_a + ignoring(instance, region) vector_b'. What does the 'ignoring' modifier do?
You are using the 'predict_linear()' function to forecast disk space exhaustion based on the metric 'node_filesystem_free_bytes'. What type of input data does predict_linear require?