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
)
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
}