func TestRemoveLocalDns(t *testing.T) {
ns0 := "nameserver 10.16.60.14\nnameserver 10.16.60.21\n"
if result := utils.RemoveLocalDns([]byte(ns0)); result != nil {
if ns0 != string(result) {
t.Fatalf("Failed No Localhost: expected \n<%s> got \n<%s>", ns0, string(result))
}
}
ns1 := "nameserver 10.16.60.14\nnameserver 10.16.60.21\nnameserver 127.0.0.1\n"
if result := utils.RemoveLocalDns([]byte(ns1)); result != nil {
if ns0 != string(result) {
t.Fatalf("Failed Localhost: expected \n<%s> got \n<%s>", ns0, string(result))
}
}
ns1 = "nameserver 10.16.60.14\nnameserver 127.0.0.1\nnameserver 10.16.60.21\n"
if result := utils.RemoveLocalDns([]byte(ns1)); result != nil {
if ns0 != string(result) {
t.Fatalf("Failed Localhost: expected \n<%s> got \n<%s>", ns0, string(result))
}
}
ns1 = "nameserver 127.0.1.1\nnameserver 10.16.60.14\nnameserver 10.16.60.21\n"
if result := utils.RemoveLocalDns([]byte(ns1)); result != nil {
if ns0 != string(result) {
t.Fatalf("Failed Localhost: expected \n<%s> got \n<%s>", ns0, string(result))
}
}
}
func (daemon *Daemon) checkLocaldns() error {
resolvConf, err := resolvconf.Get()
if err != nil {
return err
}
resolvConf = utils.RemoveLocalDns(resolvConf)
if len(daemon.config.Dns) == 0 && !bytes.Contains(resolvConf, []byte("nameserver")) {
log.Infof("No non localhost DNS resolver found in resolv.conf and containers can't use it. Using default external servers : %v", DefaultDns)
daemon.config.Dns = DefaultDns
}
return nil
}
func (container *Container) setupContainerDns() error {
if container.ResolvConfPath != "" {
return nil
}
var (
config = container.hostConfig
daemon = container.daemon
)
resolvConf, err := resolvconf.Get()
if err != nil {
return err
}
container.ResolvConfPath, err = container.getRootResourcePath("resolv.conf")
if err != nil {
return err
}
if config.NetworkMode != "host" {
// check configurations for any container/daemon dns settings
if len(config.Dns) > 0 || len(daemon.config.Dns) > 0 || len(config.DnsSearch) > 0 || len(daemon.config.DnsSearch) > 0 {
var (
dns = resolvconf.GetNameservers(resolvConf)
dnsSearch = resolvconf.GetSearchDomains(resolvConf)
)
if len(config.Dns) > 0 {
dns = config.Dns
} else if len(daemon.config.Dns) > 0 {
dns = daemon.config.Dns
}
if len(config.DnsSearch) > 0 {
dnsSearch = config.DnsSearch
} else if len(daemon.config.DnsSearch) > 0 {
dnsSearch = daemon.config.DnsSearch
}
return resolvconf.Build(container.ResolvConfPath, dns, dnsSearch)
}
// replace any localhost/127.* nameservers
resolvConf = utils.RemoveLocalDns(resolvConf)
// if the resulting resolvConf is empty, use DefaultDns
if !bytes.Contains(resolvConf, []byte("nameserver")) {
log.Infof("No non localhost DNS resolver found in resolv.conf and containers can't use it. Using default external servers : %v", DefaultDns)
// prefix the default dns options with nameserver
resolvConf = append(resolvConf, []byte("\nnameserver "+strings.Join(DefaultDns, "\nnameserver "))...)
}
}
return ioutil.WriteFile(container.ResolvConfPath, resolvConf, 0644)
}