kubernetes/docs/getting-started-guides/coreos/azure

published	title	tags
false	Weaving Kubernetes on Azure	azure, coreos, kubernetes, usecase, guide, redis, php, cloud, provisioning

Introduction

In this tutorial we will demonstrate how to deploy a Kubernetes cluster to Azure cloud. Weave makes networking of containers simple and secure, in a transparent, yet robust way. The focus of this tutorial is provide an out-of-the-box production-ready implementation with dedicated Kubernetes master and etcd nodes. It will also show how to scale the cluster with ease.

Let's go!

To get started, you need to checkout the code:

git clone https://github.com/errordeveloper/weave-demos
cd weave-demos/coreos-azure

You will need to have Node.js installed on you machine. If you have previously used Azure CLI, you should have it already.

You first need to install some of the dependencies with

npm install

Now, all you need to do is:

./azure-login.js
./create-kubernetes-cluster.js

This script will provision a cluster suitable for production use, where there is a ring of 3 dedicated etcd nodes, Kubernetes master and 2 minions. The kube-00 VM will be the master, your work loads are only to be deployed on the minion nodes, kube-01 and kube-02. Initially, all VMs are single-core, to ensure a user of the free tier can reproduce it without paying extra. Later we will show how to add more bigger VMs.

Once the creation of Azure VMs has finished, you should see the following:

...
azure_wrapper/info: Saved SSH config, you can use it like so: `ssh -F  ./output/kubernetes_1c1496016083b4_ssh_conf <hostname>`
azure_wrapper/info: The hosts in this deployment are:
 [ 'etcd-00', 'etcd-01', 'etcd-02', 'kube-00', 'kube-01', 'kube-02' ]
azure_wrapper/info: Saved state into `./output/kubernetes_1c1496016083b4_deployment.yml`

Let's login to the master node like so:

ssh -F  ./output/kubernetes_1c1496016083b4_ssh_conf kube-00

Note: config file name will be different, make sure to use the one you see.

Check there are 2 minions in the cluster:

core@kube-00 ~ $ kubectl get minions
NAME                LABELS                   STATUS
kube-01             environment=production   Ready
kube-02             environment=production   Ready

Deploying the workload

Let's follow the Guestbook example now:

cd guestbook-example
kubectl create -f redis-master.json
kubectl create -f redis-master-service.json
kubectl create -f redis-slave-controller.json
kubectl create -f redis-slave-service.json
kubectl create -f frontend-controller.json
kubectl create -f frontend-service.json

You need to wait for the pods to get deployed, run the following and wait for STATUS to change from Unknown, through Pending to Runnig.

kubectl get pods --watch

Note: the most time it will spend downloading Docker container images on each of the minions.

Eventually you should see:

POD                                    IP            CONTAINER(S)    IMAGE(S)                                HOST            LABELS                                       STATUS
redis-master                           10.2.1.4      master          dockerfile/redis                        kube-01/        name=redis-master                            Running
40d8cebd-b679-11e4-b6f6-000d3a20a034   10.2.2.4      slave           brendanburns/redis-slave                kube-02/        name=redisslave,uses=redis-master            Running
40dbdcd0-b679-11e4-b6f6-000d3a20a034   10.2.1.5      slave           brendanburns/redis-slave                kube-01/        name=redisslave,uses=redis-master            Running
421473f6-b679-11e4-b6f6-000d3a20a034   10.2.2.5      php-redis       kubernetes/example-guestbook-php-redis  kube-02/        name=frontend,uses=redisslave,redis-master   Running
4214d4fe-b679-11e4-b6f6-000d3a20a034   10.2.1.6      php-redis       kubernetes/example-guestbook-php-redis  kube-01/        name=frontend,uses=redisslave,redis-master   Running
42153c72-b679-11e4-b6f6-000d3a20a034                 php-redis       kubernetes/example-guestbook-php-redis  <unassigned>    name=frontend,uses=redisslave,redis-master   Pending

Scaling

Two single-core minions are certainly not enough for a production system of today, and, as you can see we have one unassigned pod. Let's resize the cluster by adding a couple of bigger nodes.

You will need to open another terminal window on your machine and go to the same working directory (e.g. ~/Workspace/weave-demos/coreos-azure).

First, lets set the size of new VMs:

export AZ_VM_SIZE=Large

Now, run resize script with state file of the previous deployment:

./resize-kubernetes-cluster.js ./output/kubernetes_1c1496016083b4_deployment.yml
...
azure_wrapper/info: Saved SSH config, you can use it like so: `ssh -F  ./output/kubernetes_8f984af944f572_ssh_conf <hostname>`
azure_wrapper/info: The hosts in this deployment are:
 [ 'etcd-00',
  'etcd-01',
  'etcd-02',
  'kube-00',
  'kube-01',
  'kube-02',
  'kube-03',
  'kube-04' ]
azure_wrapper/info: Saved state into `./output/kubernetes_8f984af944f572_deployment.yml`

Note: this step has created new files in ./output.

Back on kube-00:

core@kube-00 ~ $ kubectl get minions
NAME                LABELS                   STATUS
kube-01             environment=production   Ready
kube-02             environment=production   Ready
kube-03             environment=production   Ready
kube-04             environment=production   Ready

We can see that two more minions joined happily. Let's resize the number of Guestbook instances we have.

First, double-check how many replication controllers there are:

core@kube-00 ~ $ kubectl get rc
CONTROLLER             CONTAINER(S)   IMAGE(S)                                 SELECTOR          REPLICAS
frontendController     php-redis      kubernetes/example-guestbook-php-redis   name=frontend     3
redisSlaveController   slave          brendanburns/redis-slave                 name=redisslave   2

As we have 4 minions, let's resize proportionally:

core@kube-00 ~ $ kubectl resize --replicas=4 rc redisSlaveController
resized
core@kube-00 ~ $ kubectl resize --replicas=4 rc frontendController
resized

Check what we have now:

kubectl get rc
CONTROLLER             CONTAINER(S)   IMAGE(S)                                 SELECTOR          REPLICAS
frontendController     php-redis      kubernetes/example-guestbook-php-redis   name=frontend     4
redisSlaveController   slave          brendanburns/redis-slave                 name=redisslave   4

You now will have more instances of front-end Guestbook apps and Redis slaves; and, if we look up all pods labled name=frontend, we should see one running on each node.

core@kube-00 ~/guestbook-example $ kubectl get pods -l name=frontend
POD                                    IP                CONTAINER(S)  IMAGE(S)                                 HOST            LABELS                                       STATUS
4214d4fe-b679-11e4-b6f6-000d3a20a034   10.2.1.6          php-redis     kubernetes/example-guestbook-php-redis   kube-01/        name=frontend,uses=redisslave,redis-master   Running
ae59fa80-b679-11e4-b6f6-000d3a20a034   10.2.4.5          php-redis     kubernetes/example-guestbook-php-redis   kube-04/        name=frontend,uses=redisslave,redis-master   Running
421473f6-b679-11e4-b6f6-000d3a20a034   10.2.2.5          php-redis     kubernetes/example-guestbook-php-redis   kube-02/        name=frontend,uses=redisslave,redis-master   Running
42153c72-b679-11e4-b6f6-000d3a20a034   10.2.3.4          php-redis     kubernetes/example-guestbook-php-redis   kube-03/        name=frontend,uses=redisslave,redis-master   Running

Exposing the app to the outside world

To makes sure the app is working, we should load it in the browser. For accessing the Guesbook service from the outside world, I had to create an Azure endpoint like shown on the picture below.

I was then able to access it from anywhere via the Azure virtual IP for kube-01, i.e. http://104.40.211.194:8000/.

Destructing the VMs

To delete the cluster run this:

./destroy-cluster.js ./output/kubernetes_8f984af944f572_deployment.yml 

Make sure to use the latest state file, as after resizing there is a new one. By the way, with the scripts shown, you can deploy multiple clusters, if you like :)