Charmed Kubernetes will run seamlessly on
Google Cloud Platform(GCP). With the addition of the gcp-integrator,
your cluster will also be able to use GCP native features directly.
GCP Credentials
If you have set up a service account with IAM roles as your credential for Juju, there may be some additional authorisations you will need to make to access all features of GCP with Charmed Kubernetes.
If you have a GCP project set up specifically for Charmed Kubernetes, the
quickest route is to simply add the service account as an Owner of that
project in the [GCP console][owner].
If you chose a more fine-grained approach to role administration, the service account should have at least:
- roles/compute.loadBalancerAdmin
- roles/compute.instanceAdmin.v1
- roles/compute.securityAdmin
- roles/iam.serviceAccountUser
A full description of the various pre-defined roles is available in the [GCP Documentation][iam-roles].
GCP integrator
The gcp-integrator charm simplifies working with Charmed Kubernetes on
GCP. Using the credentials provided to Juju, it acts as a proxy between
Charmed Kubernetes and the underlying cloud, granting permissions to
dynamically create, for example, storage volumes.
Installing
If you install Charmed Kubernetes [using the Juju bundle][install], you can add the gcp-integrator at the same time by using the following overlay file ([download it here][asset-gcp-overlay]):
description: Charmed Kubernetes overlay to add native GCP support.
applications:
gcp-integrator:
annotations:
gui-x: "600"
gui-y: "300"
charm: cs:~containers/gcp-integrator
num_units: 1
trust: true
relations:
- ['gcp-integrator', 'kubernetes-master']
- ['gcp-integrator', 'kubernetes-worker']
To use this overlay with the Charmed Kubernetes bundle, it is specified during deploy like this:
juju deploy charmed-kubernetes --overlay ~/path/gcp-overlay.yaml --trust
… and remember to fetch the configuration file!
juju scp kubernetes-master/0:config ~/.kube/config
For more configuration options and details of the permissions which the integrator uses, please see the [charm readme][gcp-integrator-readme].
Using persistent storage
Many pods you may wish to deploy will require storage. Although you can use any type of storage supported by Kubernetes (see the [storage documentation][storage]), you also have the option to use the native GCP storage types.
GCP storage currently comes in two types - SSD (pd-ssd) or ‘standard’(pd-standard). To use these, we need to create a storage classes in Kubernetes.
For the standard disks:
kubectl create -f - <<EOY
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
name: gcp-standard
provisioner: kubernetes.io/gce-pd
parameters:
type: pd-standard
EOY
Or for SSD:
kubectl create -f - <<EOY
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
name: gcp-ssd
provisioner: kubernetes.io/gce-pd
parameters:
type: pd-ssd
EOY
You can confirm this has been added by running:
kubectl get sc
which should return:
NAME PROVISIONER AGE
gcp-ssd kubernetes.io/gce-pd 9s
gcp-standard kubernetes.io/gce-pd 45s
To actually create storage using this new class, you can make a Persistent Volume Claim:
kubectl create -f - <<EOY
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: testclaim
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 100Mi
storageClassName: gcp-standard
EOY
This should finish with a confirmation. You can check the current PVCs with:
kubectl get pvc
…which should return something similar to:
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
testclaim Bound pvc-e1d42bae-44e6-11e9-8dff-42010a840007 1Gi RWO gcp-standard 15s
This PVC can then be used by pods operating in the cluster. As an example, the following
deploys a busybox pod:
kubectl create -f - <<EOY
apiVersion: v1
kind: Pod
metadata:
name: busybox
namespace: default
spec:
containers:
- image: busybox
command:
- sleep
- "3600"
imagePullPolicy: IfNotPresent
name: busybox
volumeMounts:
- mountPath: "/pv"
name: testvolume
restartPolicy: Always
volumes:
- name: testvolume
persistentVolumeClaim:
claimName: testclaim
EOY
To set this type of storage as the default, you can use the command:
kubectl patch storageclass gcp-standard -p '{"metadata": {"annotations":{"storageclass.kubernetes.io/is-default-class":"true"}}}'
Note: If you create persistent disks and subsequently tear down the cluster, check with the GCP console to make sure all the associated resources have also been released.
Using GCP Loadbalancers
With the gcp-integrator charm in place, actions which invoke a loadbalancer in Kubernetes will automatically generate a GCP [Target Pool][target-pool] and the relevant forwarding rules. This can be demonstrated with a simple application. Here we will create a simple application and scale it to five pods:
kubectl create deployment hello-world --image=gcr.io/google-samples/node-hello:1.0
kubectl scale deployment hello-world --replicas=5
You can verify that the application and replicas have been created with:
kubectl get deployments hello-world
Which should return output similar to:
NAME READY UP-TO-DATE AVAILABLE AGE
hello-world 5/5 5 5 2m38s
To create a target pool load balancer, the application should now be exposed as a service:
kubectl expose deployment hello-world --type=LoadBalancer --name=hello --port 8080
To check that the service is running correctly:
kubectl describe service hello
…which should return output similar to:
Name: hello
Namespace: default
Labels: run=load-balancer-example
Annotations: <none>
Selector: run=load-balancer-example
Type: LoadBalancer
IP: 10.152.183.63
LoadBalancer Ingress: 34.76.144.215
Port: <unset> 8080/TCP
TargetPort: 8080/TCP
NodePort: <unset> 31864/TCP
Endpoints: 10.1.54.11:8080,10.1.54.12:8080,10.1.54.13:8080 + 2 more...
Session Affinity: None
External Traffic Policy: Cluster
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal EnsuringLoadBalancer 9m21s service-controller Ensuring load balancer
Normal EnsuredLoadBalancer 7m37s service-controller Ensured load balancer
You can see that the LoadBalancer Ingress is now associated with a new
ingress address in front of the five endpoints of the example deployment. You
can test this address:
curl 34.76.144.215:8080
Hello Kubernetes!
Upgrading the integrator-charm
The gcp-integrator is not specifically tied to the version of Charmed Kubernetes installed and may generally be upgraded at any time with the following command:
juju upgrade-charm gcp-integrator
Troubleshooting
If you have any specific problems with the gcp-integrator, you can report bugs on [Launchpad][bugs].
Any activity in GCP can be monitored from the [Operations][operations] console. If you are using a service account with IAM roles, it is relatively easy to see the actions that particular account is responsible for.
For logs of what the charm itself believes the world to look like, you can use Juju to replay the log history for that specific unit:
juju debug-log --replay --include gcp-integrator/0