If you haven’t heard yet, Rancher recently revealed news that they will be building out a new v2.0 of their popular container orchestration and management platform to be built specifically to run on top of Kubernetes. In the container realm, Kubernetes has recently become a clear favorite in the battle of orchestration and container management. There are still other options available, but it is becoming increasingly clear that Kubernetes has the largest community, user base and overall feature set so a lot of the new developments are building onto Kubernetes rather than competing with it directly. Ultimately I think this move to build on Kubernetes will be good for the container and cloud community as companies can focus more narrowly now on challenges tied specifically around security, networking, management, etc, rather than continuing to invent ways to run containers.
With Minikube and the Docker for Mac app, testing out this new Rancher 2.0 functionality is really easy. I will outline the (rough) process below, but a lot of the nuts and bolts are hidden in Minikube and Rancher. So if you’re really interested in learning about what’s happening behind the scenes, you can take a look at the Minikube and Rancher logs in greater detail.
Speaking of Minkube and Rancher, there are a few low level prerequisites you will need to have installed and configured to make this process work smoothly, which are listed out below.
- Tested on OSX
- Get Minikube working – use the Kubernetes/Minikube notes as a reference (you may need to bump memory to 4GB)
- Working version of kubectl
- Install and configure docker for mac app
I won’t cover the installation of these perquisites, but I have blogged about a few of them before and have provided links above for instructions on getting started if you aren’t familiar with any of them.
Get Rancher 2.0 working locally
The quick start guide on the Rancher website has good details for getting this working – http://rancher.com/docs/rancher/v2.0/en/quick-start-guide/. On OSX you can use the Docker for Mac app to get a current version of Docker and compose. After Docker is installed, the following command will start the Rancher container for testing.
docker run -d --restart=unless-stopped -p 8080:8080 --name rancher-server rancher/server:preview
Check that you can access the Rancher 2.0 UI by navigating to http://localhost:8080 in your browser.
If you wanted to dummy a host name to make access a little bit easier you could just add an extra entry to /etc/hosts.
You can import an existing cluster into the Rancher environment. Here we will import the local Minikube instance we got going earlier so we can test out some of the new Rancher 2.0 functionality. Alternately you could also add a host from a cloud provider.
In Rancher go to Hosts, Use Existing Kubernetes.
Then grab the IP address that your local machine is using on your network. If you aren’t familiar, on OSX you can reach into the terminal and type “ifconfig” and pull out the IP your machine is using. Also make sure to set the port to 8080, unless you otherwise modified the port map earlier when starting Rancher.
Registering the host will generate a command to run that applies configuration on the Kubernetes cluster. Just copy this kubectl command in Rancher and run it against your Minikube machine.
The above command will join Minikube into the Rancher environment and allow Rancher to manage it. Wait a minute for the Rancher components (mainly the rancher-agent continer/pod) to bootstrap into the Minikube environment. Once everything is up and running, you can check things with kubectl.
kubectl get pods --all-namespaces | grep rancher
Alternatively, to verify this, you can open the Kubernetes dashboard with the “minikube dashboard” command and see the rancher-agent running.
On the Rancher side of things, after a few minutes, you should see the Minikube instance show up in the Rancher UI.
That’s it. You now have a working Rancher 2.0 instance that is connected to a Kubernetes cluster (Minikube). Getting the environment to this point should give you enough visibility into Rancher and Kubernetes to start tinkering and learning more about the new features that Rancher 2.0 offers.
The new Rancher 2.0 UI is nice and simplifies a lot of the painful aspects of managing and administering a Kubernetes cluster. For example, on each host, there are metrics for memory, cpu, disk, etc. as well as specs about the server and its hardware. There are also built in conveniences for dealing with load balancers, secrets and other components that are normally a pain to deal with. While 2.0 is still rough around the edges, I see a lot of promise in the idea of building a management platform on top Kubernetes to make administrative tasks easier, and you can still exec to the container for the UI and check logs easily, which is one of my favorite parts about Rancher. The extra visualization is a nice touch for folks that aren’t interested in the CLI or don’t need to know how things work at a low level.
When you’re done testing, simply stop the rancher container and start it again whenever you need to test. Or just blow away the container and start over if you want to start Rancher again from scratch.