Added more to README, tweaked pod, added service, fixed validation

This commit is contained in:
markturansky 2015-04-18 07:16:07 -04:00
parent b634f17ca7
commit 2cf4e6564b
7 changed files with 72 additions and 27 deletions

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@ -3,15 +3,19 @@
The purpose of this guide is to help you become familiar with Kubernetes Persistent Volumes. By the end of the guide, we'll have
nginx serving content from your persistent volume.
This guide assumes knowledge of Kubernetes fundamentals and that a user has a cluster up and running.
This guide assumes knowledge of Kubernetes fundamentals and that you have a cluster up and running.
## Provisioning
A PersistentVolume in Kubernetes represents a real piece of underlying storage capacity in the infrastructure. Cluster administrators
must first create storage (create their GCE disks, export their NFS shares, etc.) in order for Kubernetes to mount it.
PVs are intended for "network volumes" like GCE Persistent Disks, NFS shares, and AWS ElasticBlockStore volumes. `HostPath` was included
for ease of development and testing. You'll create a local `HostPath` for this example.
PVs are intended for "network volumes" like GCE Persistent Disks, NFS shares, and AWS ElasticBlockStore volumes. ```HostPath``` was included
for ease of development and testing. You'll create a local ```HostPath``` for this example.
> IMPORTANT! For ```HostPath``` to work, you will need to run a single node cluster. Kubernetes does not
support local storage on the host at this time. There is no guarantee your pod ends up on the correct node where the ```HostPath``` resides.
```
@ -28,17 +32,17 @@ PVs are created by posting them to the API server.
cluster/kubectl.sh create -f examples/persistent-volumes/volumes/local-01.yaml
cluster/kubectl.sh get pv
NAME LABELS CAPACITY ACCESSMODES STATUS CLAIM
pv0001 map[] 10737418240 RWO Available
NAME LABELS CAPACITY ACCESSMODES STATUS CLAIM
pv0001 map[] 10737418240 RWO Available
```
## Requesting storage
Users of Kubernetes request persistent storage for their pods. They don't know how the underlying cluster is provisioned.
They just know they can rely on their claim to storage and they can manage its lifecycle independently from the many pods that may use it.
They just know they can rely on their claim to storage and can manage its lifecycle independently from the many pods that may use it.
You must be in a namespace to create claims.
Claims must be created in the same namespace as the pods that use them.
```
@ -60,7 +64,7 @@ myclaim-1 map[] Bound f5c3a89a-e50a-11e4-972f-80e6500a981e
cluster/kubectl.sh get pv
NAME LABELS CAPACITY ACCESSMODES STATUS CLAIM
NAME LABELS CAPACITY ACCESSMODES STATUS CLAIM
pv0001 map[] 10737418240 RWO Bound myclaim-1 / 6bef4c40-e50b-11e4-972f-80e6500a981e
```
@ -70,7 +74,8 @@ pv0001 map[] 10737418240 RWO
Claims are used as volumes in pods. Kubernetes uses the claim to look up its bound PV. The PV is then exposed to the pod.
```
k create -f examples/persistent-volumes/simpletest/pod.yaml
cluster/kubectl.sh create -f examples/persistent-volumes/simpletest/pod.yaml
cluster/kubectl.sh get pods
@ -78,14 +83,30 @@ POD IP CONTAINER(S) IMAGE(S) HOST LABELS
mypod 172.17.0.2 myfrontend nginx 127.0.0.1/127.0.0.1 <none> Running 12 minutes
k create -f examples/persistent-volumes/simpletest/service.json
cluster/kubectl.sh create -f examples/persistent-volumes/simpletest/service.json
cluster/kubectl.sh get services
Running: cluster/../cluster/gce/../../cluster/../_output/local/bin/darwin/amd64/kubectl --v=5 get services
NAME LABELS SELECTOR IP PORT(S)
kubernetes component=apiserver,provider=kubernetes <none> 10.0.0.2 443/TCP
kubernetes-ro component=apiserver,provider=kubernetes <none> 10.0.0.1 80/TCP
NAME LABELS SELECTOR IP PORT(S)
frontendservice <none> name=frontendhttp 10.0.0.241 3000/TCP
kubernetes component=apiserver,provider=kubernetes <none> 10.0.0.2 443/TCP
kubernetes-ro component=apiserver,provider=kubernetes <none> 10.0.0.1 80/TCP
curl 10.0.0.168:3000
I love Kubernetes storage!
```
## Next steps
You should be able to query your service endpoint and see what content nginx is serving. A "forbidden" error might mean you
need to disable SELinux (setenforce 0).
```
curl 10.0.0.241:3000
I love Kubernetes storage!
```
Hopefully this simple guide is enough to get you started with PersistentVolumes. If you have any questions, join
```#google-containers``` on IRC and ask!
Enjoy!

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@ -2,17 +2,19 @@ kind: Pod
apiVersion: v1beta3
metadata:
name: mypod
labels:
name: frontendhttp
spec:
containers:
- image: nginx
name: myfrontend
- name: myfrontend
image: dockerfile/nginx
ports:
- containerPort: 80
name: "http-server"
volumeMounts:
- mountPath: "/var/www/html"
name: mypd
volumes:
- name: mypd
source:
persistentVolumeClaim:
accessMode: ReadWriteOnce
claimRef:
name: myclaim-1
persistentVolumeClaim:
claimName: myclaim-1

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@ -0,0 +1,9 @@
{
"apiVersion": "v1beta1",
"kind": "Service",
"id": "frontendservice",
"port": 3000,
"containerPort": "http-server",
"selector": { "name": "frontendhttp" },
"createExternalLoadBalancer": false
}

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@ -319,6 +319,11 @@ func validateSource(source *api.VolumeSource) errs.ValidationErrorList {
numVolumes++
allErrs = append(allErrs, validateGlusterfs(source.Glusterfs).Prefix("glusterfs")...)
}
if source.PersistentVolumeClaimVolumeSource != nil {
numVolumes++
allErrs = append(allErrs, validatePersistentClaimVolumeSource(source.PersistentVolumeClaimVolumeSource).Prefix("glusterfs")...)
}
if numVolumes != 1 {
allErrs = append(allErrs, errs.NewFieldInvalid("", source, "exactly 1 volume type is required"))
}
@ -394,6 +399,14 @@ func validateSecretVolumeSource(secretSource *api.SecretVolumeSource) errs.Valid
return allErrs
}
func validatePersistentClaimVolumeSource(claim *api.PersistentVolumeClaimVolumeSource) errs.ValidationErrorList {
allErrs := errs.ValidationErrorList{}
if claim.ClaimName == "" {
allErrs = append(allErrs, errs.NewFieldRequired("claimName"))
}
return allErrs
}
func validateNFS(nfs *api.NFSVolumeSource) errs.ValidationErrorList {
allErrs := errs.ValidationErrorList{}
if nfs.Server == "" {

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@ -18,6 +18,7 @@ package volumeclaimbinder
import (
"fmt"
"reflect"
"time"
"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
@ -30,7 +31,6 @@ import (
"github.com/GoogleCloudPlatform/kubernetes/pkg/watch"
"github.com/golang/glog"
"reflect"
)
// PersistentVolumeClaimBinder is a controller that synchronizes PersistentVolumeClaims.
@ -94,7 +94,6 @@ func NewPersistentVolumeClaimBinder(kubeClient client.Interface, syncPeriod time
syncClaim(volumeIndex, binderClient, claim)
},
UpdateFunc: func(oldObj, newObj interface{}) {
// oldClaim := newObj.(*api.PersistentVolumeClaim)
newClaim := newObj.(*api.PersistentVolumeClaim)
if newClaim.Status.VolumeRef == nil {
syncClaim(volumeIndex, binderClient, newClaim)

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@ -17,10 +17,10 @@ limitations under the License.
package volumeclaimbinder
import (
"fmt"
"reflect"
"testing"
"fmt"
"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
"github.com/GoogleCloudPlatform/kubernetes/pkg/api/latest"
"github.com/GoogleCloudPlatform/kubernetes/pkg/api/resource"

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@ -17,9 +17,10 @@ limitations under the License.
package volumeclaimbinder
import (
"testing"
"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
"github.com/GoogleCloudPlatform/kubernetes/pkg/api/resource"
"testing"
)
func TestMatchVolume(t *testing.T) {