migrate_server.go

Documentation: k8s.io/kubernetes/cluster/images/etcd/migrate

     1  /*
     2  Copyright 2018 The Kubernetes Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package main
    18  
    19  import (
    20  	"fmt"
    21  	"os"
    22  	"os/exec"
    23  	"strings"
    24  	"time"
    25  
    26  	"k8s.io/klog/v2"
    27  )
    28  
    29  // EtcdMigrateServer manages starting and stopping a versioned etcd server binary.
    30  type EtcdMigrateServer struct {
    31  	cfg    *EtcdMigrateCfg
    32  	client EtcdMigrateClient
    33  	cmd    *exec.Cmd
    34  }
    35  
    36  // NewEtcdMigrateServer creates a EtcdMigrateServer for starting and stopping a etcd server at the given version.
    37  func NewEtcdMigrateServer(cfg *EtcdMigrateCfg, client EtcdMigrateClient) *EtcdMigrateServer {
    38  	return &EtcdMigrateServer{cfg: cfg, client: client}
    39  }
    40  
    41  // Start starts an etcd server as a separate process, waits until it has started, and returns a exec.Cmd.
    42  // TODO: Add support for listening to client via TLS.
    43  func (r *EtcdMigrateServer) Start(version *EtcdVersion) error {
    44  	etcdCmd := exec.Command(
    45  		fmt.Sprintf("%s/etcd-%s", r.cfg.binPath, version),
    46  		"--name", r.cfg.name,
    47  		"--initial-cluster", r.cfg.initialCluster,
    48  		"--debug",
    49  		"--data-dir", r.cfg.dataDirectory,
    50  		"--listen-client-urls", r.cfg.clientListenUrls,
    51  		"--advertise-client-urls", fmt.Sprintf("http://127.0.0.1:%d", r.cfg.port),
    52  		"--listen-peer-urls", r.cfg.peerListenUrls,
    53  		"--initial-advertise-peer-urls", r.cfg.peerAdvertiseUrls,
    54  	)
    55  	if r.cfg.etcdServerArgs != "" {
    56  		extraArgs := strings.Fields(r.cfg.etcdServerArgs)
    57  		etcdCmd.Args = append(etcdCmd.Args, extraArgs...)
    58  	}
    59  	fmt.Printf("Starting server %s: %+v\n", r.cfg.name, etcdCmd.Args)
    60  
    61  	etcdCmd.Stdout = os.Stdout
    62  	etcdCmd.Stderr = os.Stderr
    63  	err := etcdCmd.Start()
    64  	if err != nil {
    65  		return err
    66  	}
    67  	interval := time.NewTicker(time.Millisecond * 500)
    68  	defer interval.Stop()
    69  	done := make(chan bool)
    70  	go func() {
    71  		time.Sleep(time.Minute * 2)
    72  		close(done)
    73  	}()
    74  	for {
    75  		select {
    76  		case <-interval.C:
    77  			err := r.client.SetEtcdVersionKeyValue(version)
    78  			if err != nil {
    79  				klog.Infof("Still waiting for etcd to start, current error: %v", err)
    80  				// keep waiting
    81  			} else {
    82  				klog.Infof("Etcd on port %d is up.", r.cfg.port)
    83  				r.cmd = etcdCmd
    84  				return nil
    85  			}
    86  		case <-done:
    87  			err = etcdCmd.Process.Kill()
    88  			if err != nil {
    89  				return fmt.Errorf("error killing etcd: %v", err)
    90  			}
    91  			return fmt.Errorf("timed out waiting for etcd on port %d", r.cfg.port)
    92  		}
    93  	}
    94  }
    95  
    96  // Stop terminates the etcd server process. If the etcd server process has not been started
    97  // or is not still running, this returns an error.
    98  func (r *EtcdMigrateServer) Stop() error {
    99  	if r.cmd == nil {
   100  		return fmt.Errorf("cannot stop EtcdMigrateServer that has not been started")
   101  	}
   102  	err := r.cmd.Process.Signal(os.Interrupt)
   103  	if err != nil {
   104  		return fmt.Errorf("error sending SIGINT to etcd for graceful shutdown: %v", err)
   105  	}
   106  	gracefulWait := time.Minute * 2
   107  	stopped := make(chan bool)
   108  	timedout := make(chan bool)
   109  	go func() {
   110  		time.Sleep(gracefulWait)
   111  		close(timedout)
   112  	}()
   113  	go func() {
   114  		select {
   115  		case <-stopped:
   116  			return
   117  		case <-timedout:
   118  			klog.Infof("etcd server has not terminated gracefully after %s, killing it.", gracefulWait)
   119  			r.cmd.Process.Kill()
   120  			return
   121  		}
   122  	}()
   123  	err = r.cmd.Wait()
   124  	close(stopped)
   125  	if exiterr, ok := err.(*exec.ExitError); ok {
   126  		klog.Infof("etcd server stopped (signal: %s)", exiterr.Error())
   127  		// stopped
   128  	} else if err != nil {
   129  		return fmt.Errorf("error waiting for etcd to stop: %v", err)
   130  	}
   131  	klog.Infof("Stopped etcd server %s", r.cfg.name)
   132  	return nil
   133  }
   134
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