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Getting started with Vagrant

Prerequisites

  1. Install latest version >= 1.6.2 of vagrant from http://www.vagrantup.com/downloads.html
  2. Install latest version of Virtual Box from https://www.virtualbox.org/wiki/Downloads
  3. Install the net-tools package for your distribution for VirtualBox's private networks.
  4. Get or build a binary release

Setup

By default, the Vagrant setup will create a single kubernetes-master and 3 kubernetes-minions. Each VM will take 512 MB, so make sure you have at least 2 GB of free memory. To start your local cluster, open a shell and run:

cd kubernetes
vagrant up

Vagrant will provision each machine in the cluster with all the necessary components to run Kubernetes. The initial setup can take a few minutes to complete on each machine.

By default, each VM in the cluster is running Fedora, and all of the Kubernetes services are installed into systemd.

To access the master or any minion:

vagrant ssh master
vagrant ssh minion-1
vagrant ssh minion-2
vagrant ssh minion-3

To view the service status and/or logs on the kubernetes-master:

vagrant ssh master
[vagrant@kubernetes-master ~] $ sudo systemctl status kube-apiserver
[vagrant@kubernetes-master ~] $ sudo journalctl -r -u kube-apiserver

[vagrant@kubernetes-master ~] $ sudo systemctl status kube-controller-manager
[vagrant@kubernetes-master ~] $ sudo journalctl -r -u kube-controller-manager

[vagrant@kubernetes-master ~] $ sudo systemctl status etcd
[vagrant@kubernetes-master ~] $ sudo systemctl status nginx

To view the services on any of the kubernetes-minion(s):

vagrant ssh minion-1
[vagrant@kubernetes-minion-1] $ sudo systemctl status docker
[vagrant@kubernetes-minion-1] $ sudo journalctl -r -u docker
[vagrant@kubernetes-minion-1] $ sudo systemctl status kubelet
[vagrant@kubernetes-minion-1] $ sudo journalctl -r -u kubelet

Interacting with your Kubernetes cluster with Vagrant.

With your Kubernetes cluster up, you can manage the nodes in your cluster with the regular Vagrant commands.

To push updates to new Kubernetes code after making source changes:

vagrant provision

To stop and then restart the cluster:

vagrant halt
vagrant up

To destroy the cluster:

vagrant destroy

Once your Vagrant machines are up and provisioned, the first thing to do is to check that you can use the kubecfg.sh script. Set the KUBERNETES_PROVIDER environment variable and try to list the minions:

You may need to build the binaries first, you can do this with make

$ export KUBERNETES_PROVIDER=vagrant
$ ./cluster/kubecfg.sh list /minions
Minion identifier    Labels
----------           ----------
10.245.2.4           <none>
10.245.2.3           <none>
10.245.2.2           <none>

Interacting with your Kubernetes cluster with the kube-* scripts.

Alternatively to using the vagrant commands, you can also use the cluster/kube-*.sh scripts to interact with the vagrant based provider just like any other hosting platform for kubernetes.

All of these commands assume you have set KUBERNETES_PROVIDER appropriately:

export KUBERNETES_PROVIDER=vagrant

Bring up a vagrant cluster

cluster/kube-up.sh

Destroy the vagrant cluster

cluster/kube-down.sh

Update the vagrant cluster after you make changes (only works when building your own releases locally):

cluster/kube-push.sh

Interact with the cluster

cluster/kubecfg.sh

Authenticating with your master

When using the vagrant provider in Kubernetes, the cluster/kubecfg.sh script will cache your credentials in a ~/.kubernetes_vagrant_auth file so you will not be prompted for them in the future.

cat ~/.kubernetes_vagrant_auth
{ "User": "vagrant",
  "Password": "vagrant"}

You should now be set to use the cluster/kubecfg.sh script. For example try to list the minions that you have started with:

cluster/kubecfg.sh list minions

Running containers

Your cluster is running, you can list the minions in your cluster:

$ cluster/kubecfg.sh list /minions
Minion identifier    Labels
----------           ----------
10.245.2.4           <none>
10.245.2.3           <none>
10.245.2.2           <none>

Now start running some containers!

You can now use any of the cluster/kube-*.sh commands to interact with your VM machines. Before starting a container there will be no pods, services and replication controllers.

$ cluster/kubecfg.sh list /pods
ID                  Image(s)            Host                Labels              Status
----------          ----------          ----------          ----------          ----------

$ cluster/kubecfg.sh list /services
ID                  Labels              Selector            Port
----------          ----------          ----------          ----------

$ cluster/kubecfg.sh list /replicationControllers
ID                  Image(s)            Selector            Replicas
----------          ----------          ----------          ----------

Start a container running nginx with a replication controller and three replicas:

$ cluster/kubecfg.sh -p 8080:80 run dockerfile/nginx 3 myNginx

When listing the pods, you will see that three containers have been started and are in Waiting state:

$ cluster/kubecfg.sh list /pods
ID                                     Image(s)            Host                    Labels                          Status
----------                             ----------          ----------              ----------                      ----------
781191ff-3ffe-11e4-9036-0800279696e1   dockerfile/nginx    10.245.2.4/10.245.2.4   replicationController=myNginx   Waiting
7813c8bd-3ffe-11e4-9036-0800279696e1   dockerfile/nginx    10.245.2.2/10.245.2.2   replicationController=myNginx   Waiting
78140853-3ffe-11e4-9036-0800279696e1   dockerfile/nginx    10.245.2.3/10.245.2.3   replicationController=myNginx   Waiting

You need to wait for the provisioning to complete, you can monitor the minions by doing:

$ sudo salt '*minion-1' cmd.run 'docker images'
kubernetes-minion-1:
    REPOSITORY          TAG                 IMAGE ID            CREATED             VIRTUAL SIZE
    <none>              <none>              96864a7d2df3        26 hours ago        204.4 MB
    google/cadvisor     latest              e0575e677c50        13 days ago         12.64 MB
    kubernetes/pause    latest              6c4579af347b        8 weeks ago         239.8 kB

Once the docker image for nginx has been downloaded, the container will start and you can list it:

$ sudo salt '*minion-1' cmd.run 'docker ps'
kubernetes-minion-1:
    CONTAINER ID        IMAGE                     COMMAND                CREATED             STATUS              PORTS                    NAMES
    dbe79bf6e25b        dockerfile/nginx:latest   "nginx"                21 seconds ago      Up 19 seconds                                k8s--mynginx.8c5b8a3a--7813c8bd_-_3ffe_-_11e4_-_9036_-_0800279696e1.etcd--7813c8bd_-_3ffe_-_11e4_-_9036_-_0800279696e1--fcfa837f
    fa0e29c94501        kubernetes/pause:latest   "/pause"               8 minutes ago       Up 8 minutes        0.0.0.0:8080->80/tcp     k8s--net.a90e7ce4--7813c8bd_-_3ffe_-_11e4_-_9036_-_0800279696e1.etcd--7813c8bd_-_3ffe_-_11e4_-_9036_-_0800279696e1--baf5b21b
    aa2ee3ed844a        google/cadvisor:latest    "/usr/bin/cadvisor -   38 minutes ago      Up 38 minutes                                k8s--cadvisor.9e90d182--cadvisor_-_agent.file--4626b3a2
    65a3a926f357        kubernetes/pause:latest   "/pause"               39 minutes ago      Up 39 minutes       0.0.0.0:4194->8080/tcp   k8s--net.c5ba7f0e--cadvisor_-_agent.file--342fd561

Going back to listing the pods, services and replicationControllers, you now have:

$ cluster/kubecfg.sh list /pods
ID                                     Image(s)            Host                    Labels                          Status
----------                             ----------          ----------              ----------                      ----------
781191ff-3ffe-11e4-9036-0800279696e1   dockerfile/nginx    10.245.2.4/10.245.2.4   replicationController=myNginx   Running
7813c8bd-3ffe-11e4-9036-0800279696e1   dockerfile/nginx    10.245.2.2/10.245.2.2   replicationController=myNginx   Running
78140853-3ffe-11e4-9036-0800279696e1   dockerfile/nginx    10.245.2.3/10.245.2.3   replicationController=myNginx   Running

$ cluster/kubecfg.sh list /services
ID                  Labels              Selector            Port
----------          ----------          ----------          ----------

$ cluster/kubecfg.sh list /replicationControllers
ID                  Image(s)            Selector                        Replicas
----------          ----------          ----------                      ----------
myNginx             dockerfile/nginx    replicationController=myNginx   3

We did not start any services, hence there is none listed. But we see three replicas displayed properly. Check the guestbook application to learn how to create a service. You can already play with resizing the replicas with:

$ cluster/kubecfg.sh resize myNginx 2
$ cluster/kubecfg.sh list /pods
ID                                     Image(s)            Host                    Labels                          Status
----------                             ----------          ----------              ----------                      ----------
7813c8bd-3ffe-11e4-9036-0800279696e1   dockerfile/nginx    10.245.2.2/10.245.2.2   replicationController=myNginx   Running
78140853-3ffe-11e4-9036-0800279696e1   dockerfile/nginx    10.245.2.3/10.245.2.3   replicationController=myNginx   Running

Congratulations!

Testing

The following will run all of the end-to-end testing scenarios assuming you set your environment in cluster/kube-env.sh

hack/e2e-test.sh

Troubleshooting

I just created the cluster, but I am getting authorization errors!

You probably have an incorrect ~/.kubernetes_vagrant_auth file for the cluster you are attempting to contact.

rm ~/.kubernetes_vagrant_auth

After using kubecfg.sh make sure that the correct credentials are set:

cat ~/.kubernetes_vagrant_auth
{
  "User": "vagrant",
  "Password": "vagrant"
}

I just created the cluster, but I do not see my container running !

If this is your first time creating the cluster, the kubelet on each minion schedules a number of docker pull requests to fetch prerequisite images. This can take some time and as a result may delay your initial pod getting provisioned.

I changed Kubernetes code, but it's not running !

Are you sure there was no build error? After running $ vagrant provision, scroll up and ensure that each Salt state was completed successfully on each box in the cluster. It's very likely you see a build error due to an error in your source files!

I have brought Vagrant up but the minions won't validate !

Are you sure you built a release first? Did you install net-tools? For more clues, login to one of the minions (vagrant ssh minion-1) and inspect the salt minion log (sudo cat /var/log/salt/minion).

I want to change the number of minions !

You can control the number of minions that are instantiated via the environment variable KUBERNETES_NUM_MINIONS on your host machine. If you plan to work with replicas, we strongly encourage you to work with enough minions to satisfy your largest intended replica size. If you do not plan to work with replicas, you can save some system resources by running with a single minion. You do this, by setting KUBERNETES_NUM_MINIONS to 1 like so:

export KUBERNETES_NUM_MINIONS=1