k8s.io/apiserver@v0.29.3/pkg/storage/etcd3/preflight/checks.go (about)

     1  /*
     2  Copyright 2017 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 preflight
    18  
    19  import (
    20  	"fmt"
    21  	"math/rand"
    22  	"net"
    23  	"net/url"
    24  	"time"
    25  )
    26  
    27  const connectionTimeout = 1 * time.Second
    28  
    29  // EtcdConnection holds the Etcd server list
    30  type EtcdConnection struct {
    31  	ServerList []string
    32  }
    33  
    34  func (EtcdConnection) serverReachable(connURL *url.URL) bool {
    35  	scheme := connURL.Scheme
    36  	if scheme == "http" || scheme == "https" || scheme == "tcp" {
    37  		scheme = "tcp"
    38  	}
    39  	if conn, err := net.DialTimeout(scheme, connURL.Host, connectionTimeout); err == nil {
    40  		defer conn.Close()
    41  		return true
    42  	}
    43  	return false
    44  }
    45  
    46  func parseServerURI(serverURI string) (*url.URL, error) {
    47  	connURL, err := url.Parse(serverURI)
    48  	if err != nil {
    49  		return &url.URL{}, fmt.Errorf("unable to parse etcd url: %v", err)
    50  	}
    51  	return connURL, nil
    52  }
    53  
    54  // CheckEtcdServers will attempt to reach all etcd servers once. If any
    55  // can be reached, return true.
    56  func (con EtcdConnection) CheckEtcdServers() (done bool, err error) {
    57  	// Attempt to reach every Etcd server randomly.
    58  	serverNumber := len(con.ServerList)
    59  	serverPerms := rand.Perm(serverNumber)
    60  	for _, index := range serverPerms {
    61  		host, err := parseServerURI(con.ServerList[index])
    62  		if err != nil {
    63  			return false, err
    64  		}
    65  		if con.serverReachable(host) {
    66  			return true, nil
    67  		}
    68  	}
    69  	return false, nil
    70  }