Easier workflow for port forwarding about coreos-kubernetes

[mwarkentin]

I assume this is related to the issue I was having - I spun up the single-node Vagrant instance, and went through the whole multi-tier app configuration, without much issue. However I was unable to access the guestbook app in my browser, and I assume it's related to Vagrant port forwarding. I tried a few different changes to the Vagrantfile networking, but am unable so far to be able to access it.

Some documentation (or perhaps there's some way to handle this automatically) would be helpful. Here's my kubernetes services, if someone could provide a pointer on how I need to update vagrant:

mwarkentin@Michaels-iMac kubernetes (master) $ kubectl get services
NAME           LABELS                                    SELECTOR                IP(S)       PORT(S)
guestbook      app=guestbook                             app=guestbook           10.3.0.96   3000/TCP
kubernetes     component=apiserver,provider=kubernetes   <none>                  10.3.0.1    443/TCP
redis-master   app=redis,role=master                     app=redis,role=master   10.3.0.57   6379/TCP
redis-slave    app=redis,role=slave                      app=redis,role=slave    10.3.0.66   6379/TCP

I tried the following changes, but was still unable to view it on http://localhost:3000:

• config.vm.network "forwarded_port", guest: 3000, host: 3000
• config.vm.network "forwarded_port", guest_ip: "10.3.0.96", guest: 3000, host: 3000

[aaronlevy]

You should be able to reach the guestbook via the service NodePort on your vagrant node (no additional port forwarding needed).

The example should have set up a service with a NodePort, which you should be able to see with:

$ kubectl describe service guestbook
Name:                   guestbook
Namespace:              default
Labels:                 app=guestbook
Selector:               app=guestbook
Type:                   LoadBalancer
IP:                     10.3.0.159
Port:                   <unnamed>       3000/TCP
NodePort:               <unnamed>       30635/TCP
Endpoints:              10.2.10.3:3000,10.2.10.4:3000,10.2.10.5:3000
Session Affinity:       None
No events.

The NodePort will be randomly assigned from the range 30000-32676, so in your case the nodeport will likely be different.

Then from your local machine's browser, you should be able to see the guestbook via http://172.17.4.99:<nodeport>

[aaronlevy]

Also, for more detail on NodePorts & external services: http://kubernetes.io/v1.0/docs/user-guide/services.html#external-services

[mwarkentin]

@aaronlevy Thank you, I'll give that a shot!

[mwarkentin]

That worked! Might be helpful to have something about that in the docs. 😄

[aaronlevy]

Glad it worked. I just went through the upstream guestbook docs, and it does seem a little confusing because there is no mention of the nodeport (which is necessary for platforms that do not support cloud-provider loadbalancers). I'll open a ticket to add some documentation around this.