Kubernetes Namespaces and OpenAM




I have been conducting some experiments running the ForgeRock stack on Kubernetes. I recently stumbled on namespaces.

In a nutshell Kubernetes (k8) namespaces provide isolation for instances. The typical use case is to provide isolated environments for dev, QA, production and so on.

I had an "Aha!" moment when it occurred to me that namespaces could also provide multi-tenancy on a k8 cluster. How might this work?

Let's create a two node OpenAM cluster using an external OpenDJ instance:

See https://github.com/ForgeRock/fretes  for some samples used in this article

kubectl create -f am-dj-idm/

The above command launches all the containers found in the given directory, wires them up together (updates DNS records), and create a load balancer on GCE.

 If I look at my services:

 kubectl get service 

I see something like this:

NAME       LABELS          SELECTOR   IP(S) PORT(S) 
openam-svc name=openam-svc site=site1 10.215.249.206 80/TCP 
                                      104.197.122.164 

(note: I am eliding a bit of the output here for brevity)

 That second IP for openam-svc is the external IP of the load balancer configured by Kubernetes. If you bring up this IP address you will see the OpenAM login page. 

 Now, let's change my namespace to another instance. Say "tenant1" (I previously created this namespace)

 kc config use-context tenant1 

 A kubectl get services  should be empty, as we have no services running yet in the tenant1 namespace. 

 So let's create some: 

 kubectl create -f am-dj-idm/ 
This is the same command we ran before - but this time we are running against a different namespace.  

 Looking at our services, we see:

 NAME        LABELS            SELECTOR   IP(S) PORT(S) 
openam-svc  name=openam-svc   site=site1 10.215.255.185 80/TCP 
                                         23.251.153.176 

Pretty cool. We now have two OpenAM instances deployed, with complete isolation, on the same cluster, using only a handful of commands. 

 Hopefully this gives you a sense of why I am so excited about Kubernetes.

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