func TestDnsOptionsBasedOnHostResolvConf(t *testing.T) {
resolvConf, err := ioutil.ReadFile("/etc/resolv.conf")
if os.IsNotExist(err) {
t.Fatalf("/etc/resolv.conf does not exist")
}
hostNamservers := resolvconf.GetNameservers(resolvConf)
hostSearch := resolvconf.GetSearchDomains(resolvConf)
cmd := exec.Command(dockerBinary, "run", "--dns=127.0.0.1", "busybox", "cat", "/etc/resolv.conf")
out, _, err := runCommandWithOutput(cmd)
if err != nil {
t.Fatal(err, out)
}
if actualNameservers := resolvconf.GetNameservers([]byte(out)); string(actualNameservers[0]) != "127.0.0.1" {
t.Fatalf("expected '127.0.0.1', but says: '%s'", string(actualNameservers[0]))
}
actualSearch := resolvconf.GetSearchDomains([]byte(out))
if len(actualSearch) != len(hostSearch) {
t.Fatalf("expected '%s' search domain(s), but it has: '%s'", len(hostSearch), len(actualSearch))
}
for i := range actualSearch {
if actualSearch[i] != hostSearch[i] {
t.Fatalf("expected '%s' domain, but says: '%s'", actualSearch[i], hostSearch[i])
}
}
cmd = exec.Command(dockerBinary, "run", "--dns-search=mydomain", "busybox", "cat", "/etc/resolv.conf")
out, _, err = runCommandWithOutput(cmd)
if err != nil {
t.Fatal(err, out)
}
actualNameservers := resolvconf.GetNameservers([]byte(out))
if len(actualNameservers) != len(hostNamservers) {
t.Fatalf("expected '%s' nameserver(s), but it has: '%s'", len(hostNamservers), len(actualNameservers))
}
for i := range actualNameservers {
if actualNameservers[i] != hostNamservers[i] {
t.Fatalf("expected '%s' nameserver, but says: '%s'", actualNameservers[i], hostNamservers[i])
}
}
if actualSearch = resolvconf.GetSearchDomains([]byte(out)); string(actualSearch[0]) != "mydomain" {
t.Fatalf("expected 'mydomain', but says: '%s'", string(actualSearch[0]))
}
deleteAllContainers()
logDone("run - dns options based on host resolv.conf")
}
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)
}
func (container *Container) setupContainerDns() error {
if container.ResolvConfPath != "" {
return nil
}
var (
config = container.hostConfig
daemon = container.daemon
)
if config.NetworkMode == "host" {
container.ResolvConfPath = "/etc/resolv.conf"
return nil
}
resolvConf, err := resolvconf.Get()
if err != nil {
return err
}
// If custom dns exists, then create a resolv.conf for the container
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
}
resolvConfPath, err := container.getRootResourcePath("resolv.conf")
if err != nil {
return err
}
container.ResolvConfPath = resolvConfPath
return resolvconf.Build(container.ResolvConfPath, dns, dnsSearch)
} else {
container.ResolvConfPath = "/etc/resolv.conf"
}
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" && (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)
}
return ioutil.WriteFile(container.ResolvConfPath, resolvConf, 0644)
}
func (container *Container) setupContainerDns() error {
if container.ResolvConfPath != "" {
// check if this is an existing container that needs DNS update:
if container.UpdateDns {
// read the host's resolv.conf, get the hash and call updateResolvConf
log.Debugf("Check container (%s) for update to resolv.conf - UpdateDns flag was set", container.ID)
latestResolvConf, latestHash := resolvconf.GetLastModified()
// clean container resolv.conf re: localhost nameservers and IPv6 NS (if IPv6 disabled)
updatedResolvConf, modified := resolvconf.FilterResolvDns(latestResolvConf, container.daemon.config.EnableIPv6)
if modified {
// changes have occurred during resolv.conf localhost cleanup: generate an updated hash
newHash, err := utils.HashData(bytes.NewReader(updatedResolvConf))
if err != nil {
return err
}
latestHash = newHash
}
if err := container.updateResolvConf(updatedResolvConf, latestHash); err != nil {
return err
}
// successful update of the restarting container; set the flag off
container.UpdateDns = false
}
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.*, and remove IPv6 nameservers if IPv6 disabled in daemon
resolvConf, _ = resolvconf.FilterResolvDns(resolvConf, daemon.config.EnableIPv6)
}
//get a sha256 hash of the resolv conf at this point so we can check
//for changes when the host resolv.conf changes (e.g. network update)
resolvHash, err := utils.HashData(bytes.NewReader(resolvConf))
if err != nil {
return err
}
resolvHashFile := container.ResolvConfPath + ".hash"
if err = ioutil.WriteFile(resolvHashFile, []byte(resolvHash), 0644); err != nil {
return err
}
return ioutil.WriteFile(container.ResolvConfPath, resolvConf, 0644)
}