Stackube User Guide
=====================================
=============================
Tenant and Network Management
=============================
In this part, we will introduce tenant management and networking in Stackube. The tenant, which is ``1:1`` mapped with k8s namespace, is managed by using k8s CRD (previous TPR) to interact with Keystone. And the tenant is also ``1:1`` mapped with a network automatically, which is also implemented by CRD with standalone Neutron.
1. Create a new tenant
::
$ cat test-tenant.yaml
apiVersion: "stackube.kubernetes.io/v1"
kind: Tenant
metadata:
name: test
spec:
username: "test"
password: "password"
$ kubectl create -f test-tenant.yaml
2. Check the auto-created namespace and network. Wait a while, the namespace and network for this tenant should be created automatically:
::
$ kubectl get namespace test
NAME STATUS AGE
test Active 58m
$ kubectl -n test get network test -o yaml
apiVersion: stackube.kubernetes.io/v1
kind: Network
metadata:
clusterName: ""
creationTimestamp: 2017-08-03T11:58:31Z
generation: 0
name: test
namespace: test
resourceVersion: "3992023"
selfLink: /apis/stackube.kubernetes.io/v1/namespaces/test/networks/test
uid: 11d452eb-7843-11e7-8319-68b599b7918c
spec:
cidr: 10.244.0.0/16
gateway: 10.244.0.1
networkID: ""
status:
state: Active
3. Check the Network and Tenant created in Neutron by Stackube controller.
::
$ source ~/keystonerc_admin
$ neutron net-list
+--------------------------------------+----------------------+----------------------------------+----------------------------------------------------------+
| id | name | tenant_id | subnets |
+--------------------------------------+----------------------+----------------------------------+----------------------------------------------------------+
| 421d913a-a269-408a-9765-2360e202ad5b | kube-test-test | 915b36add7e34018b7241ab63a193530 | bb446a53-de4d-4546-81fc-8736a9a88e3a 10.244.0.0/16 |
4. Check the ``kube-dns`` pods created in the new namespace.
::
# kubectl -n test get pods
NAME READY STATUS RESTARTS AGE
kube-dns-1476438210-37jv7 3/3 Running 0 1h
5. Create pods and services in the new namespace.
::
# kubectl -n test run nginx --image=nginx
deployment "nginx" created
# kubectl -n test expose deployment nginx --port=80
service "nginx" exposed
# kubectl -n test get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE
kube-dns-1476438210-37jv7 3/3 Running 0 1h 10.244.0.4 stackube
nginx-4217019353-6gjxq 1/1 Running 0 27s 10.244.0.10 stackube
# kubectl -n test run -i -t busybox --image=busybox sh
If you don't see a command prompt, try pressing enter.
/ # nslookup nginx
Server: 10.96.0.10
Address 1: 10.96.0.10
Name: nginx
Address 1: 10.108.57.129 nginx.test.svc.cluster.local
/ # wget -O- nginx
Connecting to nginx (10.108.57.129:80)
Welcome to nginx!
Welcome to nginx!
If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.
For online documentation and support please refer to
nginx.org.
Commercial support is available at
nginx.com.
Thank you for using nginx.
- 100% |*********************************************************************| 612 0:00:00 ETA
/ #
6. Finally, remove the tenant.
::
$ kubectl delete tenant test
tenant "test" deleted
7. Check Network in Neutron is also deleted by Stackube controller
::
$ neutron net-list
+--------------------------------------+---------+----------------------------------+----------------------------------------------------------+
| id | name | tenant_id | subnets |
+--------------------------------------+---------+----------------------------------+----------------------------------------------------------+
=============================
Persistent volume
=============================
This part describes the persistent volume design and usage in Stackube.
=================
Standard Kubernetes volume
=================
Stackube is a standard upstream Kubernetes cluster, so any type of `Kubernetes volumes
`_. can be used here, for example:
::
apiVersion: v1
kind: PersistentVolume
metadata:
name: nfs
spec:
capacity:
storage: 1Mi
accessModes:
- ReadWriteMany
nfs:
# FIXME: use the right IP
server: 10.244.1.4
path: "/exports"
Please note since Stackube is a baremetal k8s cluster, cloud provider based volume are not supported by default.
But unless you are using ``emptyDir`` or ``hostPath``, we will recommend always you the ``Cinder RBD based block device as volume`` described below in Stackube, this will bring you much higher performance.
==================================
Cinder RBD based block device as volume
==================================
The reason this volume type is preferred is: by default Stackube will run most of your workloads in a VM-based Pod, in this case directory sharing is used by hypervisor based runtime for volumes mounts, but this actually has more I/O overhead than bind mount.
On the other hand, the hypervisor Pod make it possible to mount block device directly to the VM-based Pod, so we can eliminates directory sharing.
In Stackube, we use a flexvolume to directly use Cinder RBD based block device as Pod volume. The usage is very simple:
1. Create a Cinder volume (skip if you want to use a existing Cinder volume).
::
$ cinder create --name volume 1
2. Create a Pod claim to use this Cinder volume.
::
apiVersion: v1
kind: Pod
metadata:
name: web
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx
ports:
- containerPort: 80
volumeMounts:
- name: nginx-persistent-storage
mountPath: /var/lib/nginx
volumes:
- name: nginx-persistent-storage
flexVolume:
driver: "cinder/flexvolume_driver"
fsType: ext4
options:
volumeID: daa7b4e6-1792-462d-ad47-78e900fed429
Please note the name of flexvolume should be: ``cinder/flexvolume_driver``.
The ``daa7b4e6-1792-462d-ad47-78e900fed429`` is either volume ID created with Cinder or any existing available Cinder volume ID. After this yaml is applied, the related RBD device will be attached to the VM-based Pod after this is created.
========
Others
========
If your cluster is installed by ``stackube/devstack`` or following other stackube official guide, a ``/etc/kubernetes/cinder.conf`` file will be generated automatically on every node. Otherwise, you are expected to create a ``/etc/kubernetes/cinder.conf`` on every node. The contents is like:
::
[Global]
auth-url = _AUTH_URL_
username = _USERNAME_
password = _PASSWORD_
tenant-name = _TENANT_NAME_
region = _REGION_
[RBD]
keyring = _KEYRING_
and also, users need to make sure flexvolume_driver binary is in ``/usr/libexec/kubernetes/kubelet-plugins/volume/exec/cinder~flexvolume_driver/`` of every node.