populate resolv.conf with dnsname responses when in usernamespace
when using usernamespace, dnsname respondes from cni were not making it into the containers /etc/resolv.conf because of a timing issue.  this corrects that behavior.
Fixes:
@@ -914,6 +914,7 @@ func (c *Container) checkDependenciesRunning() ([]string, error) {
}
func (c *Container) completeNetworkSetup() error {
+ var outResolvConf []string
netDisabled, err := c.NetworkDisabled()
if err != nil {
return err
@@ -927,7 +928,37 @@ func (c *Container) completeNetworkSetup() error {
if c.config.NetMode == "slirp4netns" {
return c.runtime.setupRootlessNetNS(c)
}
- return c.runtime.setupNetNS(c)
+ if err := c.runtime.setupNetNS(c); err != nil {
+ return err
+ }
+ state := c.state
+ // collect any dns servers that cni tells us to use (dnsname)
+ for _, cni := range state.NetworkStatus {
+ if cni.DNS.Nameservers != nil {
+ for _, server := range cni.DNS.Nameservers {
+ outResolvConf = append(outResolvConf, fmt.Sprintf("nameserver %s", server))
+ }
+ }
+ }
+ // check if we have a bindmount for resolv.conf
+ resolvBindMount := state.BindMounts["/etc/resolv.conf"]
+ if len(outResolvConf) < 1 || resolvBindMount == "" || len(c.config.NetNsCtr) > 0 {
+ return nil
+ }
+ // read the existing resolv.conf
+ b, err := ioutil.ReadFile(resolvBindMount)
+ if err != nil {
+ return err
+ }
+ for _, line := range strings.Split(string(b), "\n") {
+ // only keep things that dont start with nameserver from the old
+ // resolv.conf file
+ if !strings.HasPrefix(line, "nameserver") {
+ outResolvConf = append([]string{line}, outResolvConf...)
+ }
+ }
+ // write and return
+ return ioutil.WriteFile(resolvBindMount, []byte(strings.Join(outResolvConf, "\n")), 0644)
}
// Initialize a container, creating it in the runtime
