Guided Exercise: Scale and Expose Applications to External Access

Deploy one web server and access it through a Kubernetes ingress; and deploy another web server and access it through an OpenShift route.

Outcomes

In this exercise, you deploy two web applications to access them through an ingress object and a route, and scale them to verify the load-balance between the pods.

Deploy two web applications.
Create a route and an ingress object to access the web applications.
Enable the sticky sessions for the web applications.
Scale the web applications to load-balance the service.

As the student user on the workstation machine, use the lab command to prepare your system for this exercise. This command ensures that the cluster is accessible.

[student@workstation ~]$ lab start deploy-routes

Procedure 4.4. Instructions

Create two web application deployments, named satir-app and sakila-app. Use the registry.ocp4.example.com:8443/httpd-app:v1 container image for both deployments.

 [student@workstation ~]$ oc login -u developer -p developer \
   https://api.ocp4.example.com:6443
 Login successful
 ...output omitted...

Change to the web-applications project.

 [student@workstation ~]$ oc project web-applications
 Now using project "web-applications" on server "https://api.ocp4.example.com:6443".
 ...output omitted...

Create the satir-app web application deployment by using the registry.ocp4.example.com:8443/redhattraining/do180-httpd-app:v1 container image. Ignore the warning message.

 [student@workstation ~]$ oc create deployment satir-app \
   --image registry.ocp4.example.com:8443/redhattraining/do180-httpd-app:v1
 Warning: would violate PodSecurity "restricted:v1.24":
 ...output omitted...
 deployment.apps/satir-app created

After a few moments, verify that the deployment is successful.

 [student@workstation ~]$ oc get pods
 NAME                         READY   STATUS    RESTARTS   ...
 satir-app-787b7d7858-5dfsh   1/1     Running   0          ...

 [student@workstation ~]$ oc status
 ...output omitted...
 deployment/satir-app deploys registry.ocp4.example.com:8443/redhattraining/do180-httpd-app:v1
   deployment #1 running for 20 seconds - 1 pod
 ...output omitted...

Create the sakila-app web application deployment by using the registry.ocp4.example.com:8443/redhattraining/do180-httpd-app:v1 image. Ignore the warning message.

 [student@workstation ~]$ oc create deployment sakila-app \
   --image registry.ocp4.example.com:8443/redhattraining/do180-httpd-app:v1
 Warning: would violate PodSecurity "restricted:v1.24":
 ...output omitted...
 deployment.apps/sakila-app created

Wait a few moments and then verify that the deployment is successful.

 [student@workstation ~]$ oc get pods
 NAME                     READY   STATUS    RESTARTS   ...
 sakila-app-6694...5kpd   1/1     Running   0          ...
 satir-app-787b7...dfsh   1/1     Running   0          ...

 [student@workstation ~]$ oc status
 ...output omitted...
 deployment/satir-app deploys registry.ocp4.example.com:8443/redhattraining/do180-httpd-app:v1
   deployment #1 running for 5 minutes - 1 pod

 deployment/sakila-app deploys registry.ocp4.example.com:8443/redhattraining/do180-httpd-app:v1
   deployment #1 running for 2 minutes - 1 pod
 ...output omitted...

Create services for the web application deployments. Then, use the services to create a route for the satir-app application and an ingress object for the sakila-app application.

Expose the satir-app deployment. Name the service satir-svc, and specify port 8080 as the port and target port.

 [student@workstation ~]$ oc expose deployment satir-app --name satir-svc \
   --port 8080 --target-port 8080
 service/satir-svc exposed

Expose the sakila-app deployment to create the sakila-svc service.

 [student@workstation ~]$ oc expose deployment sakila-app --name sakila-svc \
   --port 8080 --target-port 8080
 service/sakila-svc exposed

Verify the status of the services.

 [student@workstation ~]$ oc get services
 NAME         TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)    ...
 sakila-svc   ClusterIP   172.30.230.41   <none>        8080/TCP   ...
 satir-svc    ClusterIP   172.30.143.15   <none>        8080/TCP   ...

 [student@workstation ~]$ oc get endpoints
 NAME         ENDPOINTS        ...
 sakila-svc   10.8.0.66:8080   ...
 satir-svc    10.8.0.65:8080   ...

 [student@workstation ~]$ oc get pods -o wide
 NAME                    READY  STATUS   RESTARTS  AGE   IP        ...
 sakila-app-6694...5kpd  1/1    Running  0         92s   10.8.0.66 ...
 satir-app-787b7...dfsh  1/1    Running  0         2m49s 10.8.0.65 ...

Create a route named satir for the satir-app web application by exposing the satir-svc service.

 [student@workstation ~]$ oc expose service satir-svc --name satir
 route.route.openshift.io/satir exposed

 [student@workstation ~]$ oc get routes
 NAME    HOST/PORT                                    ... SERVICES    PORT   ...
 satir   satir-web-applications.apps.ocp4.example.com ... satir-svc   8080   ...

Create an ingress object named ingr-sakila for the sakila-svc service. Configure the --rule option with the following values:

| Field | Value | | --- | --- | | Host | ingr-sakila.apps.ocp4.example.com | | Service name | sakila-svc | | Port number | 8080 |

 [student@workstation ~]$ oc create ingress ingr-sakila \
   --rule "ingr-sakila.apps.ocp4.example.com/*=sakila-svc:8080"
 ingress.networking.k8s.io/ingr-sakila created

 [student@workstation ~]$ oc get ingress
 NAME        ... HOSTS                              ADDRESS       PORTS ...
 ingr-sakila ... ingr-sakila.apps.ocp4.example.com  router...com  80    ...

Confirm that a route exists for the ingr-sakila ingress object.

 [student@workstation ~]$ oc get routes
 NAME           HOST/PORT                                    ... SERVICES   PORT
 ingr-sakila... ingr-sakila.apps.ocp4.example.com            ... sakila-svc <all>
 satir          satir-web-applications.apps.ocp4.example.com ... satir-svc  8080

A specific port is not assigned to routes that ingress objects created. By contrast, a route that an exposed service created is assigned the same ports as the service.

Use the curl command to access the ingr-sakila ingress object and the satir route. The output states the name of the pod that is servicing the request.

 [student@workstation ~]$ curl ingr-sakila.apps.ocp4.example.com
 Welcome to Red Hat Training, from sakila-app-66947cdd78-x5kpd

 [student@workstation ~]$ curl satir-web-applications.apps.ocp4.example.com
 Welcome to Red Hat Training, from satir-app-787b7d7858-bdfsh

Scale the web application deployments to load-balance their services. Scale the sakila-app to two replicas, and the satir-app to three replicas.

Scale the sakila-app deployment with two replicas.

 [student@workstation ~]$ oc scale deployment sakila-app --replicas 2
 deployment.apps/sakila-app scaled

Wait a few moments and then verify the status of the replica pods.

 [student@workstation ~]$ oc get pods
 NAME                     READY   STATUS    RESTARTS   ...
 sakila-app-6694...5kpd   1/1     Running   0          ...
 sakila-app-6694...rfzg   1/1     Running   0          ...
 satir-app-787b...dfsh    1/1     Running   0          ...

Scale the satir-app deployment with three replicas.

 [student@workstation ~]$ oc scale deployment satir-app --replicas 3
 deployment.apps/satir-app scaled

Wait a few moments and then verify the status of the replica pods.

 [student@workstation ~]$ oc get pods -o wide
 NAME                    READY  STATUS   RESTARTS  ... IP        ...
 sakila-app-6694...5kpd  1/1    Running  0         ... 10.8.0.66 ...
 sakila-app-6694...rfzg  1/1    Running  0         ... 10.8.0.67 ...
 satir-app-787b...dfsh   1/1    Running  0         ... 10.8.0.65 ...
 satir-app-787b...z8xm   1/1    Running  0         ... 10.8.0.69 ...
 satir-app-787b...7bhj   1/1    Running  0         ... 10.8.0.70 ...

Retrieve the service endpoints to confirm that the services are load-balanced between the additional replica pods.

 [student@workstation ~]$ oc get endpoints
 NAME         ENDPOINTS                                     ...
 sakila-svc   10.8.0.66:8080,10.8.0.67:8080                 ...
 satir-svc    10.8.0.65:8080,10.8.0.69:8080,10.8.0.70:8080  ...

Enable the sticky sessions for the sakila-app web application. Then, use the curl command to confirm that the sticky sessions are working for the ingr-sakila object.

Configure a cookie for the ingr-sakila ingress object.

 [student@workstation ~]$ oc annotate ingress ingr-sakila \
   ingress.kubernetes.io/affinity=cookie
 ingress.networking.k8s.io/ingr-sakila annotated

Use the curl command to access the ingr-sakila ingress object. The output states the name of the pod that is servicing the request. Notice that the connection is load-balanced between the replicas.

 [student@workstation ~]$ for i in {1..3}; do \
   curl ingr-sakila.apps.ocp4.example.com ; done
 Welcome to Red Hat Training, from sakila-app-66947cdd78-x5kpd
 Welcome to Red Hat Training, from sakila-app-66947cdd78-xrfzg
 Welcome to Red Hat Training, from sakila-app-66947cdd78-x5kpd

Use the curl command to save the ingr-sakila ingress object cookie to the /tmp/cookie_jar file. Confirm that the cookie exists in the /tmp/cookie_jar file.

 [student@workstation ~]$ curl ingr-sakila.apps.ocp4.example.com \
   -c /tmp/cookie_jar
 Welcome to Red Hat Training, from sakila-app-66947cdd78-xrfzg

 [student@workstation ~]$ cat /tmp/cookie_jar
 ...output omitted...
 #HttpOnly_ingr-sakila.apps.ocp4.example.com    FALSE    /    FALSE    0    b9b484110526b4b1b3159860d3aebe04    921e139c5145950d00424bf3b0a46d22

The cookie provides session stickiness for connections to the ingr-sakila route. Use the curl command and the cookie in the /tmp/cookie_jar file to connect to the ingr-sakila route again. Confirm that you are connected to the same pod that handled the request in the previous step.

 [student@workstation ~]$ for i in {1..3}; do \
   curl ingr-sakila.apps.ocp4.example.com -b /tmp/cookie_jar; done
 Welcome to Red Hat Training, from sakila-app-66947cdd78-xrfzg
 Welcome to Red Hat Training, from sakila-app-66947cdd78-xrfzg
 Welcome to Red Hat Training, from sakila-app-66947cdd78-xrfzg

Use the curl command to connect to the ingr-sakila route without the cookie. Observe that session stickiness occurs only with the cookie.

 [student@workstation ~]$ for i in {1..3}; do \
   curl ingr-sakila.apps.ocp4.example.com ; done
 Welcome to Red Hat Training, from sakila-app-66947cdd78-x5kpd
 Welcome to Red Hat Training, from sakila-app-66947cdd78-xrfzg
 Welcome to Red Hat Training, from sakila-app-66947cdd78-x5kpd

Enable the sticky sessions for the satir-app web application. Then, use the curl command to confirm that sticky sessions are active for the satir route.

Configure a cookie with a hello value for the satir route.

 [student@workstation ~]$ oc annotate route satir \
   router.openshift.io/cookie_name="hello"
 route.route.openshift.io/satir annotated

Use the curl command to access the satir route. The output states the name of the pod that is servicing the request. Notice that the connection is load-balanced between the three replica pods.

 [student@workstation ~]$ for i in {1..3}; do \
   curl satir-web-applications.apps.ocp4.example.com; done
 Welcome to Red Hat Training, from satir-app-787b7d7858-bdfsh
 Welcome to Red Hat Training, from satir-app-787b7d7858-gz8xm
 Welcome to Red Hat Training, from satir-app-787b7d7858-q7bhj

Use the curl command to save the hello cookie to the /tmp/cookie_jar file. Afterward, confirm that the hello cookie exists in the /tmp/cookie_jar file.

 [student@workstation ~]$ curl satir-web-applications.apps.ocp4.example.com \
   -c /tmp/cookie_jar
 Welcome to Red Hat Training, from satir-app-787b7d7858-q7bhj

 [student@workstation ~]$ cat /tmp/cookie_jar
 ...output omitted...
 #HttpOnly_satir-web-applications.apps.ocp4.example.com    FALSE    /    FALSE    0    hello    b7dd73d32003e513a072e25a32b6c881

The hello cookie provides session stickiness for connections to the satir route. Use the curl command and the hello cookie in the /tmp/cookie_jar file to connect to the satir route again. Confirm that you are connected to the same pod that handled the request in the previous step.

 [student@workstation ~]$ for i in {1..3}; do \
   curl satir-web-applications.apps.ocp4.example.com -b /tmp/cookie_jar; done
 Welcome to Red Hat Training, from satir-app-787b7d7858-q7bhj
 Welcome to Red Hat Training, from satir-app-787b7d7858-q7bhj
 Welcome to Red Hat Training, from satir-app-787b7d7858-q7bhj

Use the curl command to connect to the satir route without the hello cookie. Observe that session stickiness occurs only with the cookie.

 [student@workstation ~]$ for i in {1..3}; do \
   curl satir-web-applications.apps.ocp4.example.com; done
 Welcome to Red Hat Training, from satir-app-787b7d7858-gz8xm
 Welcome to Red Hat Training, from satir-app-787b7d7858-q7bhj
 Welcome to Red Hat Training, from satir-app-787b7d7858-bdfsh

Finish

On the workstation machine, use the lab command to complete this exercise. This step is important to ensure that resources from previous exercises do not impact upcoming exercises.

[student@workstation ~]$ lab finish deploy-routes

Guided Exercise: Scale and Expose Applications to External Access

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