Lab 1. Deploy your first application¶
Learn how to deploy an application to a Kubernetes cluster hosted within the IBM Container Service.
0. Prerequisites¶
Make sure you satisfy the prerequisites as outlined in Lab 0
1. Deploy the guestbook application¶
In this part of the lab we will deploy an application called guestbook
that has already been built and uploaded to DockerHub under the name
ibmcom/guestbook:v1
.
- Start by running
guestbook
:
kubectl create deployment guestbook --image=ibmcom/guestbook:v1
This action will take a bit of time. To check the status of the running application,
you can use $ kubectl get pods
.
You should see output similar to the following:
kubectl get pods
Eventually, the status should show up as Running
.
$ kubectl get pods
NAME READY STATUS RESTARTS AGE
guestbook-59bd679fdc-bxdg7 1/1 Running 0 1m
The end result of the run command is not just the pod containing our application containers, but a Deployment resource that manages the lifecycle of those pods.
- Once the status reads
Running
, we need to expose that deployment as a service so we can access it through the IP of the worker nodes. Theguestbook
application listens on port 3000. Run:
kubectl expose deployment guestbook --type="NodePort" --port=3000
- To find the port used on that worker node, examine your new service:
$ kubectl get service guestbook
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
guestbook NodePort 10.10.10.253 <none> 3000:31208/TCP 1m
We can see that our <nodeport>
is 31208
. We can see in the output the port mapping from 3000 inside
the pod exposed to the cluster on port 31208. This port in the 31000 range is automatically chosen,
and could be different for you.
guestbook
is now running on your cluster, and exposed to the internet. We need to find out where it is accessible. The worker nodes running in the container service get external IP addresses. Get the workers for your cluster and note one (any one) of the public IPs listed on the<public-IP>
line. Replace$CLUSTER_NAME
with your cluster name unless you have this environment variable set.
$ kubectl get nodes -o wide
NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME
10.185.199.3 Ready master,worker 63d v1.16.2+283af84 10.185.199.3 169.59.228.215 Red Hat 3.10.0-1127.13.1.el7.x86_64 cri-o://1.16.6-17.rhaos4.3.git4936f44.el7
10.185.199.6 Ready master,worker 63d v1.16.2+283af84 10.185.199.6 169.47.78.51 Red Hat 3.10.0-1127.13.1.el7.x86_64 cri-o://1.16.6-17.rhaos4.3.git4936f44.el7
We can see that our <EXTERNAL-IP>
is 169.59.228.215
.
- Now that you have both the address and the port, you can now access the application in the web browser
at
<public-IP>:<nodeport>
. In the example case this is173.193.99.136:31208
.
Congratulations, you've now deployed an application to Kubernetes!
When you're all done, continue to the next lab of this course.