The Day Your Laptop Became A Micro-Datacenter

Did you know that you can push your laptop from being an ordinary computer to a Micro-Datacenter powering a cluster and then back to an ordinary computer in only 15 minutes? Kubernetes Yes, you read right. 15 minutes to get your own private Kubernetes cluster up and running on your laptop. Microservices and Kubernetes are the hype. But how do you get started with more about these two exciting topics? learning I will show you every step of the way and get you up to speed with a learning environment on your laptop. By the end of this post you will be all set to experiment and explore Kubernetes on your laptop. The diagram below gives you an overview of what your Micro-Datacenter will look like when we are done setting it up. We will leverage a virtualisation layer (consisting of containers and virtual machines) running on your laptop hardware. Docker On this virtualisation layer we will run which will help us with setting up and managing our Micro-Datacenter as well as the Kubernetes cluster. Rancher Here are the 5 short steps to build your Micro-Datacenter Install the dependencies ( & ) Docker Virtualbox Install Rancher Server Create a environment in Rancher Kubernetes Add two nodes (virtual machines) to the Kubernetes cluster Run a ‘Hello World’ service in Kubernetes nginx First things first. 1. Install the Dependencies There are only two dependencies to get us on our way: We need Docker installed on your laptop ( and follow the instructions to install Docker) click here We need Virtualbox installed on your laptop ( and follow the instructions to install Virtualbox) click here Take a minute and install them both if you have not done so already. When you are done with installing go ahead and start Docker. Docker is running The screen shots and terminal commands in this post are taken from a Mac. However, with very few exceptions (which I will point out) you should be fine following along on either Linux or Windows. Let’s get started (check your watch :) 2. Install Rancher Server will manage our Micro-Datacenter and our Kubernetes cluster. Let’s fire up Rancher in a Docker container. Rancher Server Open a terminal on your laptop and copy-paste the following command (one line): > docker run -d --restart=unless-stopped -p 8080:8080 rancher/server:stable ### The Rancher Server will take some time to get up and running.### You can tail the logs to check Rancher's progress> docker psCONTAINER ID IMAGE rancher/server:stable 4a3dcbaaa4ba > docker logs -f 4a3dcbaaa4ba Once Rancher is up and running you can point your browser to and access the Rancher Server’s web interface. localhost port 8080 Later on we want our two Kubernetes nodes (virtual machines) to connect to the Rancher Server. The two nodes will not be able to use the localhost address to connect. Therefore we need to add an alias to the localhost interface on our laptop. Let’s assign a as an alias. private IP address I have chosen as a random private IP address. Note it does not matter what private IP address you choose. You will be fine as long as you stay clear of the more common ones (like 192.168…. or 10.0….). Staying clear of these ranges of private IPs will help avoiding networking conflicts. 10.145.10.1 Note for Windows users: Assigning the alias might be somewhat different on Windows. Please use caution and read up on the details for your OS. For Linux users the below commands should look very similar. ### Add the alias > sudo ifconfig lo0 alias /24 10.145.10.1 ### Check with to see whether the alias has been added ifconfig > ifconfig ** **_nd6 options=201 _ lo0: flags=8049 mtu 16384options=1203 inet 127.0.0.1 netmask 0xff000000inet6 ::1 prefixlen 128inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1 inet 10.145.10.1 netmask 0xffffff00 Verify that you can reach the Rancher Server web interface by pointing your browser to the alias on 10.145.10.1 port 8080 3. Create the Kubernetes environment in Rancher At the top left corner on the Rancher web interface click on then select Environment Manage Environments > Add Environment Give the new environment a name (ie ‘Kubernetes Demo’). Choose the Environment Template, then scroll down and click ‘Create’. Kubernetes Create a Kubernetes Environment You will now see new environment in the drop down in the top left corner. Click on it. ‘Kubernetes Demo’ Environment At this stage Rancher is waiting for us to add infrastructure nodes to the newly created Kubernetes environment. Rancher waits for infrastructure nodes to be added 4. Add two nodes (virtual machines) to the Kubernetes cluster We create the two virtual machines using the command from Docker (note you could add as many nodes as your hardware can support, but for the demo two are enough). docker-machine For our two Kubernetes nodes we could use any Linux distro machine image that comes with Docker installed. However, Rancher distributes a tiny container optimised image called . We’ll use Rancher OS. It is perfect for our use case. Rancher OS Go back to your terminal and copy-paste the command from the box below (one line). Note: once with and then with to create our two nodes. run the command twice kube-box-1 kube-box-2 ### Create a Rancher OS virtual machine with 3G of RAM (one line) > docker-machine create -d virtualbox --virtualbox-memory "3072" --virtualbox-boot2docker-url **kube-box-1 https://releases.rancher.com/os/latest/rancheros.iso ** ### Run the command again now for the second node > docker-machine create -d virtualbox --virtualbox-memory "3072" --virtualbox-boot2docker-url https://releases.rancher.com/os/latest/rancheros.iso kube-box-2 Rancher OS comes with Docker pre-installed. Unfortunately, the default version of Docker is newer than Kubernetes likes its Docker to be. We have to to a suitable version (1.13.1). switch Docker on the two nodes Login to each of the two nodes and change the Docker version. ### ssh to kube-box-1 > docker-machine ssh kube-box-1 ### and switch the Docker version to 1.13.1 then logout [docker@ ~]$ sudo ros engine switch docker-1.13.1[docker@ ~]$ exit kube-box-1 kube-box-1 ### then for the second node do the same > docker-machine ssh kube-box-2 [docker@ ~]$ sudo ros engine switch docker-1.13.1[docker@ ~]$ exit kube-box-2 kube-box-2 Fantastic. Our two nodes are now ready to join the Kubernetes cluster. In the next step we will run a little script on both of the two nodes to register them with Rancher and join the Kubernetes environment. For the registration script we will need the nodes’ IP addresses (note your nodes’ IP addresses might be different). ### Retrieve the IP address for kube-box-1 > docker-machine ip kube-box-1192.168.99.100 ### and the IP address for kube-box-2 > docker-machine ip kube-box-2 192.168.99.101 We have got all the info we need. It’s time to go back to the Rancher web interface and click on ‘Add a host’ Add a host Keep the default ‘ ’ setting for the new node. Custom Then scroll down to step 4. There specify the IP address for as retrieved above ( or whatever the value is that has allocated in your case). kube-box-1 192.168.99.100 docker-machine Rancher needs the IP address to communicate with its infrastructure nodes. Enter the node’s IP address and copy the registration script Copy the command from step 5. This is the registration script to run the Rancher agent on . kube-box-1 Go back to the terminal on your laptop and login to using the command we already used above. kube-box-1 docker-machine ssh ### ssh to kube-box-1 > docker-machine ssh kube-box-1 ### on run the script from the Rancher web interface kube-box-1 [docker@ ~]$ sudo docker run -e CATTLE_AGENT_IP=" ” -d --privileged -v /var/run/docker.sock:/var/run/docker.sock -v /var/lib/rancher:/var/lib/rancher rancher/agent:v1.2.1 kube-box-1 192.168.99.100 http://10.145.10.1:8080/v1/scripts/F6FC06D291DDADE7F0B7:1483142400000:8dr5IQ1NsrNG2pEX2hLh7XPppI ### wait for the command to complete then logout [docker@ ~]$ exit kube-box-1 Do all of the above (starting from ‘Add a host’) again to register kube-box-2. Important! Remember to copy-paste the IP address for (ie ) in step 5. Bad things will happen if you register kube-box-2 with kube-box-1’s IP address. kube-box-2 192.168.99.101 Rancher is now busy provisioning the two nodes with the Kubernetes services. Switch to to watch the Kubernetes services coming up on the two nodes. Infrastructure > Hosts Rancher provisions Kubernetes services on the two nodes It will take some time for Rancher to download and install the images for the Kubernetes services on the two nodes. Be patient. Depending on your internet connection this might take quite some time. There are several ways to tell when your Kubernetes cluster is configured and up and running. One way is when Rancher will start providing a link to open the Kubernetes dashboard ( ). Kubernetes > Dashboard You have some time while Rancher is hard at work spinning up your Kubernetes cluster. Have a play with Rancher’s web interface to see what else it offers that we did not discuss yet. Kubernetes is ready. You might want to checkout the Kubernetes dashboard. 5. Run a ‘Hello World’ nginx service in Kubernetes Now, to the exiting part! We have Kubernetes running in our Micro-Datacenter. In good old fashioned tradition let’s run the ‘Hello World’ of Microservices: A simple web server (serving a default web page). nginx Kubernetes provides the command line tool to configure its resources. kubectl With Rancher Server we can either choose to run from the console in the web interface or kubectl if you have installed on your laptop then Rancher gives us the configuration file to copy over to the laptop. kubectl kubectl Both options are available from the menu in the Rancher web interface. Kubernetes > CLI For simplicity we will use Rancher’s web console for running kubectl. Of course you are free to on your laptop and configure it with the config provided by Rancher (click on the button as shown on the screen shot below). Having installed on your laptop will come in handy when you start doing more interesting stuff with your Kubernetes cluster later. install kubectl ‘Generate Config’ kubectl kubectl shell in the Rancher web interface (or check out the config file if you run kubectl on your laptop) For your convenience I created a with the Kubernets configuration files ( ) to run the nginx ‘Hello World’ example. github repo *.yaml All you need to run the nginx example (a Kubernetes deployment and Kubernetes service) is executing the two ‘ commands in Rancher’s web console. kubectl create -f …’ Clone the if you either intend to run from your laptop or you want to study the content of the two files. github repo kubectl yaml ### Copy-paste the commands and enter them on Rancher's web console ### Create a deployment (spinning up two nginx pods) > kubectl create -f https://raw.githubusercontent.com/danaschwanden/micro-datacenter/master/HelloWorld/nginx-deployment.yaml deployment “dep-nginx” created ### Check to see the deployment we just created > kubectl get deployments _NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGEdep-nginx 2 _ 2 2 2 6s ### Check to see the two pods the deployment created > kubectl get pods NAME READY STATUS RESTARTS AGEdep-nginx-3655994670–2gks0 1/1 Running 0 10sdep-nginx-3655994670–53dfd 1/1 Running 0 10s ### Create a service to expose the nginx services on the two nodes > kubectl create -f https://raw.githubusercontent.com/danaschwanden/micro-datacenter/master/HelloWorld/nginx-service.yaml service “svc-nginx” created ### The service is configured to use “NodePort”### Kubernetes master will allocate a random port from a### flag-configured range (default: 30000–32767)### Let's check on what port the service exposes nginx > kubectl get services NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGEsvc-nginx 10.43.164.192 8080: 32767 /TCP 12s Note the output of the command above. It tells us two things: ‘kubectl get services’ The nginx service ( ) is exposed on the external IP svc-nginx on port (might be different in your case). 32767 This means nginx is now available on both our on port . nodes 32767 Let’s verify that we can reach nginx by pointing the browser to either of the nodes’ IP addresses at the port the Kubernetes service has assigned. For example to access nginx via . Note that your IP address and port might be different. Change them accordingly. http://192.168.99.100:32767 kube-box-1 Et voila . Your laptop is running a Micro-Datacenter with Kubernetes and nginx as a simple show case service. Congratulations Over to you now to play with the setup at your heart’s content. We barely touched the surface of what can be done. Go wild. I hope you will enjoy your new datacenter powers. Once you are done you probably want to clean up and free up the resources. Cleaning up is just as easy as it was to set up the environment. Simply follow the 5 steps below. Cleaning up As promised we want to leave your laptop as pristine as we found it at the beginning of this post. Let’s get the broom out. a) Stop the Kubernetes service and deployment. ### In the Rancher web interface console run > kubectl delete service svc-nginx service “svc-nginx” deleted > kubectl delete deployment dep-nginx deployment “dep-nginx” deleted b) Stop the two nodes and remove them ### In the terminal on your laptop run > docker-machine stop kube-box-1 > docker-machine stop kube-box-2 > docker-machine rm kube-box-1 > docker-machine rm kube-box-2 c) Remove the alias on your laptop’s localhost interface. If you are on Windows or Linux this step might be slightly different. Please use caution and read up on it for your OS. ### In the terminal on your laptop run > sudo ifconfig lo0 10.145.10.1 -alias d) Stop the Rancher Server container and remove it ### In the terminal on your laptop run > docker psCONTAINER ID IMAGE rancher/server:v1.6.3 4a3dcbaaa4ba > docker stop **4a3dcbaaa4ba**> docker rm 4a3dcbaaa4ba > docker imagesREPOSITORY TAG IMAGE ID rancher/server v1.6.3 b4c15b304585 > docker rmi b4c15b304585 Done. I hope you enjoyed the journey (have you checked the time?) PS: As always: . “The opinions stated here are my own, not those of my company” Useful Links The that inspired this one Rancher post The Rancher documentation The Rancher OS documentation The Kubernetes documentation The nginx documentation