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Merge pull request #51645 from jingxu97/Aug/nameserver

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Automatic merge from submit-queue (batch tested with PRs 51186, 50350, 51751, 51645, 51837)

Set up DNS server in containerized mounter path

During NFS/GlusterFS mount, it requires to have DNS server to be able to
resolve service name. This PR gets the DNS server ip from kubelet and
add it to the containerized mounter path. So if containerized mounter is
used, service name could be resolved during mount
**Release note**:

```release-note
Allow DNS resolution of service name for COS using containerized mounter.  It fixed the issue with DNS resolution of NFS and Gluster services.
```
This commit is contained in:
Kubernetes Submit Queue 2017-09-05 17:30:09 -07:00 committed by GitHub
commit e8d99f5839
2 changed files with 37 additions and 1 deletions
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2
cluster/gce/gci/configure-helper.sh
View File

@ -1201,7 +1201,7 @@ function prepare-mounter-rootfs {
mount --make-rshared "${CONTAINERIZED_MOUNTER_ROOTFS}/var/lib/kubelet"
mount --bind -o ro /proc "${CONTAINERIZED_MOUNTER_ROOTFS}/proc"
mount --bind -o ro /dev "${CONTAINERIZED_MOUNTER_ROOTFS}/dev"
mount --bind -o ro /etc/resolv.conf "${CONTAINERIZED_MOUNTER_ROOTFS}/etc/resolv.conf"
cp /etc/resolv.conf "${CONTAINERIZED_MOUNTER_ROOTFS}/etc/"
}
# A helper function for removing salt configuration and comments from a file.

36
pkg/kubelet/kubelet.go
View File

@ -19,11 +19,13 @@ package kubelet
import (
"crypto/tls"
"fmt"
"io/ioutil"
"net"
"net/http"
"net/url"
"os"
"path"
"path/filepath"
"sort"
"strings"
"sync"
@ -760,7 +762,11 @@ func NewMainKubelet(kubeCfg *kubeletconfiginternal.KubeletConfiguration,
// check node capabilities since the mount path is not the default
if len(kubeCfg.ExperimentalMounterPath) != 0 {
kubeCfg.ExperimentalCheckNodeCapabilitiesBeforeMount = false
// Replace the nameserver in containerized-mounter's rootfs/etc/resolve.conf with kubelet.ClusterDNS
// so that service name could be resolved
klet.setupDNSinContainerizedMounter(kubeCfg.ExperimentalMounterPath)
}
// setup volumeManager
klet.volumeManager = volumemanager.NewVolumeManager(
kubeCfg.EnableControllerAttachDetach,
@ -2141,6 +2147,36 @@ func (kl *Kubelet) cleanUpContainersInPod(podID types.UID, exitedContainerID str
}
}
// Replace the nameserver in containerized-mounter's rootfs/etc/resolve.conf with kubelet.ClusterDNS
func (kl *Kubelet) setupDNSinContainerizedMounter(mounterPath string) {
resolvePath := filepath.Join(strings.TrimSuffix(mounterPath, "/mounter"), "rootfs", "etc", "resolv.conf")
dnsString := ""
for _, dns := range kl.clusterDNS {
dnsString = dnsString + fmt.Sprintf("nameserver %s\n", dns)
}
if kl.resolverConfig != "" {
f, err := os.Open(kl.resolverConfig)
defer f.Close()
if err != nil {
glog.Error("Could not open resolverConf file")
} else {
_, hostSearch, err := kl.parseResolvConf(f)
if err != nil {
glog.Errorf("Error for parsing the reslov.conf file: %v", err)
} else {
dnsString = dnsString + "search"
for _, search := range hostSearch {
dnsString = dnsString + fmt.Sprintf(" %s", search)
}
dnsString = dnsString + "\n"
}
}
}
if err := ioutil.WriteFile(resolvePath, []byte(dnsString), 0600); err != nil {
glog.Errorf("Could not write dns nameserver in file %s, with error %v", resolvePath, err)
}
}
// isSyncPodWorthy filters out events that are not worthy of pod syncing
func isSyncPodWorthy(event *pleg.PodLifecycleEvent) bool {
// ContatnerRemoved doesn't affect pod state