benchmark

README

Scheduler Performance Test

Motivation

We already have a performance testing system -- Kubemark. However, Kubemark requires setting up and bootstrapping a whole cluster, which takes a lot of time.

We want to have a standard way to reproduce scheduling latency metrics result and benchmark scheduler as simple and fast as possible. We have the following goals:

• Save time on testing
  • The test and benchmark can be run in a single box. We only set up components necessary to scheduling without booting up a cluster.
• Profiling runtime metrics to find out bottleneck
  • Write scheduler integration test but focus on performance measurement. Take advantage of go profiling tools and collect fine-grained metrics, like cpu-profiling, memory-profiling and block-profiling.
• Reproduce test result easily
  • We want to have a known place to do the performance related test for scheduler. Developers should just run one script to collect all the information they need.

Currently the test suite has the following:

• benchmark
  • make use of go test -bench and report nanosecond/op.
  • schedule b.N pods when the cluster has N nodes and P scheduled pods. Since it takes relatively long time to finish one round, b.N is small: 10 - 100.

How To Run

Benchmark tests

# In Kubernetes root path
make test-integration WHAT=./test/integration/scheduler_perf ETCD_LOGLEVEL=warn KUBE_TEST_VMODULE="''" KUBE_TEST_ARGS="-run=^$$ -benchtime=1ns -bench=BenchmarkPerfScheduling"

The benchmark suite runs all the tests specified under config/performance-config.yaml. By default, it runs all workloads that have the "performance" label. In the configuration, labels can be added to a test case and/or individual workloads. Each workload also has all labels of its test case. The perf-scheduling-label-filter command line flag can be used to select workloads. It works like GitHub label filtering: the flag accepts a comma-separated list of label names. Each label may have a + or - as prefix. Labels with + or no prefix must be set for a workload for it to be run. - means that the label must not be set. For example, this runs all performance benchmarks except those that are labeled as "fast":

make test-integration WHAT=./test/integration/scheduler_perf ETCD_LOGLEVEL=warn KUBE_TEST_VMODULE="''" KUBE_TEST_ARGS="-run=^$$ -benchtime=1ns -bench=BenchmarkPerfScheduling -perf-scheduling-label-filter=performance,-fast"

Once the benchmark is finished, JSON file with metrics is available in the current directory (test/integration/scheduler_perf). Look for BenchmarkPerfScheduling_benchmark_YYYY-MM-DDTHH:MM:SSZ.json. You can use -data-items-dir to generate the metrics file elsewhere.

In case you want to run a specific test in the suite, you can specify the test through -bench flag:

Also, bench time is explicitly set to 1ns (-benchtime=1ns flag) so each test is run only once. Otherwise, the golang benchmark framework will try to run a test more than once in case it ran for less than 1s.

# In Kubernetes root path
make test-integration WHAT=./test/integration/scheduler_perf ETCD_LOGLEVEL=warn KUBE_TEST_VMODULE="''" KUBE_TEST_ARGS="-run=^$$ -benchtime=1ns -bench=BenchmarkPerfScheduling/SchedulingBasic/5000Nodes/5000InitPods/1000PodsToSchedule"

To produce a cpu profile:

# In Kubernetes root path
make test-integration WHAT=./test/integration/scheduler_perf KUBE_TIMEOUT="-timeout=3600s" ETCD_LOGLEVEL=warn KUBE_TEST_VMODULE="''" KUBE_TEST_ARGS="-run=^$$ -benchtime=1ns -bench=BenchmarkPerfScheduling -cpuprofile ~/cpu-profile.out"

How to configure benchmark tests

Configuration file located under config/performance-config.yaml contains a list of templates. Each template allows to set:

• node manifest
• manifests for initial and testing pod
• number of nodes, number of initial and testing pods
• templates for PVs and PVCs
• feature gates

See op data type implementation in scheduler_perf_test.go for available operations to build WorkloadTemplate.

Initial pods create a state of a cluster before the scheduler performance measurement can begin. Testing pods are then subject to performance measurement.

The configuration file under config/performance-config.yaml contains a default list of templates to cover various scenarios. In case you want to add your own, you can extend the list with new templates. It's also possible to extend op data type, respectively its underlying data types to extend configuration of possible test cases.

Logging

The default verbosity is 2 (the recommended value for production). -v can be used to change this. The log format can be changed with -logging-format=text|json. The default is to write into a log file (when using the text format) or stderr (when using JSON). Together these options allow simulating different real production configurations and to compare their performance.

During interactive debugging sessions it is possible to enable per-test output via -use-testing-log.

Integration tests

To run integration tests, use:

make test-integration WHAT=./test/integration/scheduler_perf KUBE_TEST_ARGS=-use-testing-log

Integration testing uses the same config/performance-config.yaml as benchmarking. By default, workloads labeled as integration-test are executed as part of integration testing. -test-scheduling-label-filter can be used to change that.

Documentation

Index

• type DataItem
• type DataItems

Types

type DataItem

type DataItem struct {
	// Data is a map from bucket to real data point (e.g. "Perc90" -> 23.5). Notice
	// that all data items with the same label combination should have the same buckets.
	Data map[string]float64 `json:"data"`
	// Unit is the data unit. Notice that all data items with the same label combination
	// should have the same unit.
	Unit string `json:"unit"`
	// Labels is the labels of the data item.
	Labels map[string]string `json:"labels,omitempty"`
}

DataItem is the data point.

type DataItems

type DataItems struct {
	Version   string     `json:"version"`
	DataItems []DataItem `json:"dataItems"`
}

DataItems is the data point set. It is the struct that perf dashboard expects.