Installation

Follow these instructions to locally set up a 3 node kubernetes cluster with 1 dedicated master containing a single Etcd. All nodes will be running calico and containerd.

Pre-requisites

In order to follow these instruction you need to install

• Vagrant
• kubectl

These instructions have been tested to work with version vagrant 2.2.4 on OS X Mojave.

Create a 'local' kubernetes cluster running Calico & Containerd

If at any point you want to reset things, destroy all VMs by running:

vagrant destroy --force

1. Clone this repo

2. If you want to bring up a 3 node cluster with 1 dedicated master using one command, run this at the repo root

vagrant up

Alternatively, you can also bring up each node separately: you must start with the master node:

vagrant up k8s-master

Once this has been provisioned you can either first connect to the cluster (see 3.), or directly proceed to provision the other nodes:

vagrant up k8s-node-{i}, i=1,2,3 (order doesn't matter here)

3. The kube config for your new cluster was copied for you to .kube/config - tell kubectl to use it by running

export KUBECONFIG=$(PWD)/.kube/config

4. Check that everything so far is working by running

kubectl get nodes -owide

You should see (with potentially different VERSION, OS-Image, KERNEL-VERSION, CONTAINER-RUNTIME):

NAME         STATUS   ROLES    AGE   VERSION   INTERNAL-IP      EXTERNAL-IP   OS-IMAGE                KERNEL-VERSION              CONTAINER-RUNTIME
k8s-master   Ready    master   47m   v1.14.1   192.168.205.10   <none>        CentOS Linux 7 (Core)   3.10.0-957.5.1.el7.x86_64   containerd://1.2.4
k8s-node-1   Ready    <none>   43m   v1.14.1   192.168.205.11   <none>        CentOS Linux 7 (Core)   3.10.0-957.5.1.el7.x86_64   containerd://1.2.4
k8s-node-2   Ready    <none>   39m   v1.14.1   192.168.205.12   <none>        CentOS Linux 7 (Core)   3.10.0-957.5.1.el7.x86_64   containerd://1.2.4
k8s-node-3   Ready    <none>   35m   v1.14.1   192.168.205.13   <none>        CentOS Linux 7 (Core)   3.10.0-957.5.1.el7.x86_64   containerd://1.2.4

You might have to wait for a minute or so until all nodes are have STATUS: Ready - if this is not what you see take a look at the logs in 2. to figure out what went wrong.

At this point you've got a functioning kubernetes cluster. Read on to see how to connect to an nginx webserver via node port and local DNS.

Connect via NodePort

Run (if not done already)

export KUBECONFIG=$(PWD)/.kube/config

to connect to your local kubernetes cluster you installed in the previous section. Then execute the following to create an nginx pod in context namespace (likely 'default'):

kubectl run nginx-server --image nginx --port=80

Next, run

kubectl expose deployment nginx-server --type=NodePort

to expose this server via node port. Once completed, we can find the node port by running (requires jq to be installed)

kubectl get svc -ojson | jq '.items[] | select(.metadata.name == "nginx-server")'.spec.ports[].nodePort

Alternatively,

kubectl get svc nginx-server

and manually parse the node port value.

In this example assume that the node port for the nginx-server service was set to 30730: use any of the node 'INTERNAL-IP' values, e.g. let's take 192.168.205.10, and you should be able to curl 192.168.205.10:30730 or open it in a browser.

Local DNS setup

While it might be enough to connect via IP & node port let's take a look at setting up a local DNS server using dnsmasq.

On OS X the installation of dnsmasq is straightforward:

brew install dnsmasq

Then run the dnsmasq service by doing

sudo brew services start dnsmasq

(note the sudo!)

Edit /usr/local/etc/dnsmasq.conf and add

address=/local-dev/192.168.205.10

Here, local-dev will be the domain we want to route to 192.168.205.10 (the master node IP address - but any of the other node IPs would work as well). Pick any domain name you like but make sure to keep things consistent in what follows. Also, don't use any actual real domains because e.g. Chrome might insist that all connections use HTTPS.

Restart the dnsmasq service (using sudo again!):

sudo brew services restart dnsmasq

Check this works by running

dig test.local-dev @localhost

You should be seeing

...
;; ANSWER SECTION:
test.local-dev.		0	IN	A	192.168.205.10
...

Next we need to tell OS X about local-dev. Create the /etc/resolver directory by running

sudo mkdir /etc/resolver

Then execute

sudo tee /etc/resolver/local-dev >/dev/null <<EOF
nameserver 127.0.0.1
EOF

Finally either open a web browser (or use curl) at

http://mytest.local-dev:30730/

The mytest.local-dev domain is an example, in fact a.local-dev would work as well.