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	This commit adds two new global options to kubectl: --profile and --profile-output, writing out go profiles to disk to debug interesting and unexpected kubectl behaviour. As an example, here is how to capture a block file, eg. for how long are we blocked on I/O and where? $ kubectl get nodes --profile=mutex -v6 $ go tool pprof -png ./profile.pprof > out.png $ google-chrome out.png Fixes: #68679
		
			
				
	
	
		
			89 lines
		
	
	
		
			2.0 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			89 lines
		
	
	
		
			2.0 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
/*
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Copyright 2017 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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    http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package cmd
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import (
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	"fmt"
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	"os"
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	"runtime"
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	"runtime/pprof"
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	"github.com/spf13/pflag"
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)
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var (
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	profileName   string
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	profileOutput string
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)
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func addProfilingFlags(flags *pflag.FlagSet) {
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	flags.StringVar(&profileName, "profile", "none", "Name of profile to capture. One of (none|cpu|heap|goroutine|threadcreate|block|mutex)")
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	flags.StringVar(&profileOutput, "profile-output", "profile.pprof", "Name of the file to write the profile to")
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}
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func initProfiling() error {
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	switch profileName {
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	case "none":
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		return nil
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	case "cpu":
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		f, err := os.Create(profileOutput)
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		if err != nil {
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			return err
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		}
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		return pprof.StartCPUProfile(f)
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	// Block and mutex profiles need a call to Set{Block,Mutex}ProfileRate to
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	// output anything. We choose to sample all events.
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	case "block":
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		runtime.SetBlockProfileRate(1)
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		return nil
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	case "mutex":
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		runtime.SetMutexProfileFraction(1)
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		return nil
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	default:
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		// Check the profile name is valid.
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		if profile := pprof.Lookup(profileName); profile == nil {
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			return fmt.Errorf("unknown profile '%s'", profileName)
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		}
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	}
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	return nil
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}
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func flushProfiling() error {
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	switch profileName {
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	case "none":
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		return nil
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	case "cpu":
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		pprof.StopCPUProfile()
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	case "heap":
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		runtime.GC()
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		fallthrough
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	default:
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		profile := pprof.Lookup(profileName)
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		if profile == nil {
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			return nil
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		}
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		f, err := os.Create(profileOutput)
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		if err != nil {
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			return err
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		}
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		profile.WriteTo(f, 0)
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	}
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	return nil
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}
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