forked from kubernetes/kops
/
etcd_cluster.go
257 lines (213 loc) · 6.58 KB
/
etcd_cluster.go
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package protokube
import (
"bytes"
"fmt"
"github.com/ghodss/yaml"
"github.com/golang/glog"
"io/ioutil"
"os"
"path"
"strings"
"time"
)
type EtcdCluster struct {
PeerPort int
ClientPort int
LogFile string
DataDirName string
ClusterName string
ClusterToken string
Me *EtcdNode
Nodes []*EtcdNode
PodName string
CPURequest string
Spec *EtcdClusterSpec
VolumeMountPath string
}
func (e *EtcdCluster) String() string {
return DebugString(e)
}
type EtcdNode struct {
Name string
InternalName string
}
func (e *EtcdNode) String() string {
return DebugString(e)
}
type EtcdController struct {
kubeBoot *KubeBoot
volume *Volume
volumeSpec *EtcdClusterSpec
cluster *EtcdCluster
}
func newEtcdController(kubeBoot *KubeBoot, v *Volume, spec *EtcdClusterSpec) (*EtcdController, error) {
k := &EtcdController{
kubeBoot: kubeBoot,
}
modelTemplatePath := path.Join(kubeBoot.ModelDir, spec.ClusterKey+".config")
modelTemplate, err := ioutil.ReadFile(modelTemplatePath)
if err != nil {
return nil, fmt.Errorf("error reading model template %q: %v", modelTemplatePath, err)
}
cluster := &EtcdCluster{}
cluster.Spec = spec
cluster.VolumeMountPath = v.Mountpoint
model, err := ExecuteTemplate("model-etcd-"+spec.ClusterKey, string(modelTemplate), cluster)
if err != nil {
return nil, fmt.Errorf("error executing etcd model template %q: %v", modelTemplatePath, err)
}
err = yaml.Unmarshal([]byte(model), cluster)
if err != nil {
return nil, fmt.Errorf("error parsing etcd model template %q: %v", modelTemplatePath, err)
}
k.cluster = cluster
return k, nil
}
func (k *EtcdController) RunSyncLoop() {
for {
err := k.syncOnce()
if err != nil {
glog.Warningf("error during attempt to bootstrap (will sleep and retry): %v", err)
}
time.Sleep(1 * time.Minute)
}
}
func (k *EtcdController) syncOnce() error {
return k.cluster.configure(k.kubeBoot)
}
func (c *EtcdCluster) configure(k *KubeBoot) error {
name := c.ClusterName
if !strings.HasPrefix(name, "etcd") {
// For sanity, and to avoid collisions in directories / dns
return fmt.Errorf("unexpected name for etcd cluster (must start with etcd): %q", name)
}
if c.LogFile == "" {
c.LogFile = "/var/log/" + name + ".log"
}
if c.PodName == "" {
c.PodName = c.ClusterName
}
if c.CPURequest == "" {
c.CPURequest = "100m"
}
err := touchFile(PathFor(c.LogFile))
if err != nil {
return fmt.Errorf("error touching log-file %q: %v", c.LogFile, err)
}
if c.ClusterToken == "" {
c.ClusterToken = "etcd-cluster-token-" + name
}
var nodes []*EtcdNode
for _, nodeName := range c.Spec.NodeNames {
name := name + "-" + nodeName
fqdn := k.BuildInternalDNSName(name)
node := &EtcdNode{
Name: name,
InternalName: fqdn,
}
nodes = append(nodes, node)
if nodeName == c.Spec.NodeName {
c.Me = node
err := k.CreateInternalDNSNameRecord(fqdn)
if err != nil {
return fmt.Errorf("error mapping internal dns name for %q: %v", name, err)
}
}
}
c.Nodes = nodes
if c.Me == nil {
return fmt.Errorf("my node name %s not found in cluster %v", c.Spec.NodeName, strings.Join(c.Spec.NodeNames, ","))
}
manifestTemplatePath := "templates/etcd/manifest.template"
manifestTemplate, err := ioutil.ReadFile(manifestTemplatePath)
if err != nil {
return fmt.Errorf("error reading etcd manifest template %q: %v", manifestTemplatePath, err)
}
manifest, err := ExecuteTemplate("etcd-manifest", string(manifestTemplate), c)
if err != nil {
return fmt.Errorf("error executing etcd manifest template: %v", err)
}
// Time to write the manifest!
// To avoid a possible race condition where the manifest survives a reboot but the volume
// is not mounted or not yet mounted, we use a symlink from /etc/kubernetes/manifests/<name>.manifest
// to a file on the volume itself. Thus kubelet cannot launch the manifest unless the volume is mounted.
manifestSource := "/etc/kubernetes/manifests/" + name + ".manifest"
manifestTargetDir := path.Join(c.VolumeMountPath, "k8s.io", "manifests")
manifestTarget := path.Join(manifestTargetDir, name+".manifest")
writeManifest := true
{
// See if the manifest has changed
existingManifest, err := ioutil.ReadFile(PathFor(manifestTarget))
if err != nil {
if !os.IsNotExist(err) {
return fmt.Errorf("error reading manifest file %q: %v", manifestTarget, err)
}
} else if bytes.Equal(existingManifest, manifest) {
writeManifest = false
} else {
glog.Infof("Need to update manifest file: %q", manifestTarget)
}
}
createSymlink := true
{
// See if the symlink is correct
stat, err := os.Lstat(PathFor(manifestSource))
if err != nil {
if !os.IsNotExist(err) {
return fmt.Errorf("error reading manifest symlink %q: %v", manifestSource, err)
}
} else if (stat.Mode() & os.ModeSymlink) != 0 {
// It's a symlink, make sure the target matches
target, err := os.Readlink(PathFor(manifestSource))
if err != nil {
return fmt.Errorf("error reading manifest symlink %q: %v", manifestSource, err)
}
if target == manifestTarget {
createSymlink = false
} else {
glog.Infof("Need to update manifest symlink (wrong target %q): %q", target, manifestSource)
}
} else {
glog.Infof("Need to update manifest symlink (not a symlink): %q", manifestSource)
}
}
if createSymlink || writeManifest {
err = os.Remove(PathFor(manifestSource))
if err != nil && !os.IsNotExist(err) {
return fmt.Errorf("error removing etcd manifest symlink (for strict creation) %q: %v", manifestSource, err)
}
err = os.MkdirAll(PathFor(manifestTargetDir), 0755)
if err != nil {
return fmt.Errorf("error creating directories for etcd manifest %q: %v", manifestTargetDir, err)
}
err = ioutil.WriteFile(PathFor(manifestTarget), manifest, 0644)
if err != nil {
return fmt.Errorf("error writing etcd manifest %q: %v", manifestTarget, err)
}
// Note: no PathFor on the target, because it's a symlink and we want it to evaluate on the host
err = os.Symlink(manifestTarget, PathFor(manifestSource))
if err != nil {
return fmt.Errorf("error creating etcd manifest symlink %q -> %q: %v", manifestSource, manifestTarget, err)
}
glog.Infof("Updated etcd manifest: %s", manifestSource)
}
return nil
}
func touchFile(p string) error {
_, err := os.Lstat(p)
if err == nil {
return nil
}
if !os.IsNotExist(err) {
return fmt.Errorf("error getting state of file %q: %v", p, err)
}
f, err := os.Create(p)
if err != nil {
return fmt.Errorf("error touching file %q: %v", p, err)
}
err = f.Close()
if err != nil {
return fmt.Errorf("error closing touched file %q: %v", p, err)
}
return nil
}