This repository hosts the CSI Hostpath driver and all of its build and dependent configuration files to deploy the driver.
- Kubernetes cluster
- Running verrsion 1.13 or later
- Access to terminal with
kubectl
installed
The easiest way to test the Hostpath driver is to run deploy/deploy-hostpath.sh
scrip as show:
$ sh deploy/deploy-hostpath.sh
You should see an output similar to the following printed on the terminal showing the application of rbac rules and the result of deploying the hostpath driver, external privisioner and external attacher components:
applying RBAC rules
serviceaccount/csi-provisioner created
clusterrole.rbac.authorization.k8s.io/external-provisioner-runner created
clusterrolebinding.rbac.authorization.k8s.io/csi-provisioner-role created
role.rbac.authorization.k8s.io/external-provisioner-cfg created
rolebinding.rbac.authorization.k8s.io/csi-provisioner-role-cfg created
serviceaccount/csi-attacher created
clusterrole.rbac.authorization.k8s.io/external-attacher-runner created
clusterrolebinding.rbac.authorization.k8s.io/csi-attacher-role created
role.rbac.authorization.k8s.io/external-attacher-cfg created
rolebinding.rbac.authorization.k8s.io/csi-attacher-role-cfg created
serviceaccount/csi-snapshotter created
clusterrole.rbac.authorization.k8s.io/external-snapshotter-runner created
clusterrolebinding.rbac.authorization.k8s.io/csi-snapshotter-role created
deploying hostpath components
service/csi-hostpath-attacher created
statefulset.apps/csi-hostpath-attacher created
statefulset.apps/csi-hostpathplugin created
service/csi-hostpath-provisioner created
statefulset.apps/csi-hostpath-provisioner created
deploying snapshotter
service/csi-hostpath-snapshotter created
statefulset.apps/csi-hostpath-snapshotter created
The script can also install CRDs that are needed for alpha features, but as this is something that should be done by the cluster provisioning tool it is disabled in the script by default. For this and other customizations see the source code of the deploy script.
Next, validate the deployment. First, ensure all expected pods are running properly including the external attacher, provisioner, and the actual hostpath driver plugin:
$ kubectl get pods
NAME READY STATUS RESTARTS AGE
csi-hostpath-attacher-0 1/1 Running 0 5m47s
csi-hostpath-provisioner-0 1/1 Running 0 5m47s
csi-hostpath-snapshotter-0 1/1 Running 0 5m47s
csi-hostpathplugin-0 2/2 Running 0 5m45s
From the root directory, deploy the application pods including a storage class, a PVC, and a pod which mounts a volume using the Hostpath driver found in directory ./examples
:
$ kubectl create -f ./examples
pod/my-csi-app created
persistentvolumeclaim/csi-pvc created
storageclass.storage.k8s.io/csi-hostpath-sc created
Let's validate the components are deployed:
$> kubectl get pv
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
pvc-58d5ec38-03e5-11e9-be51-000c29e88ff1 1Gi RWO Delete Bound default/csi-pvc csi-hostpath-sc 80s
$> kubectl get pvc
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
csi-pvc Bound pvc-58d5ec38-03e5-11e9-be51-000c29e88ff1 1Gi RWO csi-hostpath-sc 93s
Finally, inspect the application pod my-csi-app
which mounts a Hostpath volume:
$> kubectl describe pods/my-csi-app
Name: my-csi-app
Namespace: default
Priority: 0
PriorityClassName: <none>
Node: 127.0.0.1/127.0.0.1
Start Time: Wed, 19 Dec 2018 18:25:29 -0500
Labels: <none>
Annotations: <none>
Status: Running
IP: 172.17.0.5
Containers:
my-frontend:
Container ID: docker://927dc537fd14704794e1167b75a5aa040eb86eff76e155672be65c5cf9bda798
Image: busybox
Image ID: docker-pullable://busybox@sha256:2a03a6059f21e150ae84b0973863609494aad70f0a80eaeb64bddd8d92465812
Port: <none>
Host Port: <none>
Command:
sleep
1000000
State: Running
Started: Wed, 19 Dec 2018 18:25:33 -0500
Ready: True
Restart Count: 0
Environment: <none>
Mounts:
/data from my-csi-volume (rw)
/var/run/secrets/kubernetes.io/serviceaccount from default-token-wm562 (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
my-csi-volume:
Type: PersistentVolumeClaim (a reference to a PersistentVolumeClaim in the same namespace)
ClaimName: csi-pvc
ReadOnly: false
default-token-wm562:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-wm562
Optional: false
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute for 300s
node.kubernetes.io/unreachable:NoExecute for 300s
Events: <none>
The Hostpath driver is configured to create new volumes under /tmp
inside the hostpath container that is specified in the plugin DaemonSet found here. This path persist as long as the DaemonSet pod is up and running.
A file written in a properly mounted Hostpath volume inside an application should show up inside the Hostpath container. The following steps confirms that Hostpath is working properly. First, create a file from the application pod as shown:
$ kubectl exec -it my-csi-app /bin/sh
/ # touch /data/hello-world
/ # exit
Next, ssh into the Hostpath container and verify that the file shows up there:
$ kubectl exec -it $(kubectl get pods --selector app=csi-hostpathplugin -o jsonpath='{.items[*].metadata.name}') -c hostpath /bin/sh
Then, use the following command to locate the file. If everything works OK you should get a result similar to the following:
/ # find / -name hello-world
/tmp/057485ab-c714-11e8-bb16-000c2967769a/hello-world
/ # exit
An additional way to ensure the driver is working properly is by inspecting the VolumeAttachment API object created that represents the attached volume:
$> kubectl describe volumeattachment
Name: csi-a7515d53b30a1193fd70b822b18181cff1d16422fd922692bce5ea234cb191e9
Namespace:
Labels: <none>
Annotations: <none>
API Version: storage.k8s.io/v1
Kind: VolumeAttachment
Metadata:
Creation Timestamp: 2018-12-19T23:25:29Z
Resource Version: 533
Self Link: /apis/storage.k8s.io/v1/volumeattachments/csi-a7515d53b30a1193fd70b822b18181cff1d16422fd922692bce5ea234cb191e9
UID: 5fb4874f-03e5-11e9-be51-000c29e88ff1
Spec:
Attacher: csi-hostpath
Node Name: 127.0.0.1
Source:
Persistent Volume Name: pvc-58d5ec38-03e5-11e9-be51-000c29e88ff1
Status:
Attached: true
Events: <none>
If you want to build the driver yourself, you can do so with the following command from the root directory:
make hostpath
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