k8s_deep_dive session

Cloning to Git Repo:

jatinrajpal@Jatins-MacBook-Air demo % git clone https://github.com/rajpaljatin19/k8s_deep_dive.git
Cloning into 'k8s_deep_dive'...
remote: Enumerating objects: 22, done.
remote: Counting objects: 100% (22/22), done.
remote: Compressing objects: 100% (16/16), done.
remote: Total 22 (delta 1), reused 0 (delta 0), pack-reused 0
Receiving objects: 100% (22/22), 7.22 KiB | 7.22 MiB/s, done.
Resolving deltas: 100% (1/1), done.

Running an app locally:

Navigate to k8s_deep_dive/app directory and run the app manually

jatinrajpal@Jatins-MacBook-Air demo % cd k8s_deep_dive/app
jatinrajpal@Jatins-MacBook-Air app % export FLASK_APP=prog.py
jatinrajpal@Jatins-MacBook-Air app % flask run
 * Serving Flask app 'prog.py'
 * Debug mode: off
WARNING: This is a development server. Do not use it in a production deployment. Use a production WSGI server instead.
 * Running on http://127.0.0.1:5000
Press CTRL+C to quit

Running app via Docker

Navigate to k8s_deep_dive/docker directory and run docker build command to build the app

jatinrajpal@Jatins-MacBook-Air demo % cd ../docker
jatinrajpal@Jatins-MacBook-Air docker % docker build -t demoapp .
[+] Building 10.9s (9/9) FINISHED
 => [internal] load build definition from Dockerfile                                                         0.0s
 => => transferring dockerfile: 230B                                                                         0.0s
 => [internal] load .dockerignore                                                                            0.0s
 => => transferring context: 2B                                                                              0.0s
 => [internal] load metadata for docker.io/library/python:3.9-slim-buster                                    4.5s
 => [internal] load build context                                                                            0.0s
 => => transferring context: 747B                                                                            0.0s
 => [1/4] FROM docker.io/library/python:3.9-slim-buster@sha256:0ac1e4889c90d3117680b33cbdd397e3d95098b4c6bc  3.2s
 => => resolve docker.io/library/python:3.9-slim-buster@sha256:0ac1e4889c90d3117680b33cbdd397e3d95098b4c6bc  0.0s
 => => sha256:0ac1e4889c90d3117680b33cbdd397e3d95098b4c6bcff8600035fa5343527ed 988B / 988B                   0.0s
 => => sha256:a9fe8430888821244e2f80688dfa0d5bddb233c65160977326a54235b383fc8f 1.37kB / 1.37kB               0.0s
 => => sha256:89a1e068e9a2a7fbec57ccd79a1455269208c430c275b9d5c933b0dd121454ae 6.90kB / 6.90kB               0.0s
 => => sha256:cfe0f778e53ce031ef449bc02975a07f2568716dea807ed2f390d352c0001972 25.92MB / 25.92MB             1.8s
 => => sha256:a8e11a7826c6ce9b3366e1d2c4dfbdec39133e62fe15bca830f2947fd1064b6c 2.65MB / 2.65MB               1.8s
 => => sha256:b1c45cd4de1898925eafc2e4113923f17a98fff25b028f350aab970ed5f411e9 11.19MB / 11.19MB             1.2s
 => => sha256:f47ec9e5e8c3402a60c0f6194af85b8a96af980ae1368d7afcfd98cabc9348f4 242B / 242B                   1.5s
 => => sha256:8fcba38b80a230d869a3f1e8053026976cd8f63bc8c02bb86e558d0566e57c7e 3.19MB / 3.19MB               2.0s
 => => extracting sha256:cfe0f778e53ce031ef449bc02975a07f2568716dea807ed2f390d352c0001972                    0.7s
 => => extracting sha256:a8e11a7826c6ce9b3366e1d2c4dfbdec39133e62fe15bca830f2947fd1064b6c                    0.1s
 => => extracting sha256:b1c45cd4de1898925eafc2e4113923f17a98fff25b028f350aab970ed5f411e9                    0.3s
 => => extracting sha256:f47ec9e5e8c3402a60c0f6194af85b8a96af980ae1368d7afcfd98cabc9348f4                    0.0s
 => => extracting sha256:8fcba38b80a230d869a3f1e8053026976cd8f63bc8c02bb86e558d0566e57c7e                    0.1s
 => [2/4] WORKDIR /app                                                                                       0.1s
 => [3/4] RUN pip install flask                                                                              2.9s
 => [4/4] COPY . .                                                                                           0.0s
 => exporting to image                                                                                       0.1s
 => => exporting layers                                                                                      0.1s
 => => writing image sha256:0523a04ecfee671e5f06753534f5125e18a5b2f084baa5b2f4f5bd541d425d1a                 0.0s
 => => naming to docker.io/library/demoapp                                                                   0.0s

Verify of the image is created post running docker build command

jatinrajpal@Jatins-MacBook-Air docker % docker image ls
REPOSITORY                                 TAG       IMAGE ID       CREATED         SIZE
demoapp                                    latest    0523a04ecfee   8 seconds ago   122MB

Run docker run command to run your containerized application locally on the machine

jatinrajpal@Jatins-MacBook-Air docker % docker run -p 8000:8000 demoapp
 * Serving Flask app 'prog.py'
 * Debug mode: off
WARNING: This is a development server. Do not use it in a production deployment. Use a production WSGI server instead.
 * Running on all addresses (0.0.0.0)
 * Running on http://127.0.0.1:8000
 * Running on http://172.17.0.2:8000
Press CTRL+C to quit

Now that your flask webservice is up and running, call your service to make sure you are getting the desired output (via seperate terminal)

jatinrajpal@Jatins-MacBook-Air ~ % curl -v http://127.0.0.1:8000
*   Trying 127.0.0.1:8000...
* Connected to 127.0.0.1 (127.0.0.1) port 8000 (#0)
> GET / HTTP/1.1
> Host: 127.0.0.1:8000
> User-Agent: curl/7.86.0
> Accept: */*
>
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< Server: Werkzeug/2.2.3 Python/3.9.16
< Date: Mon, 03 Apr 2023 06:40:10 GMT
< Content-Type: text/html; charset=utf-8
< Content-Length: 157
< Connection: close
<
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>FlaskBlog</title>
</head>
<body>
   <h1>Welcome to my Blog</h1>
</body>
* Closing connection 0
</html>%

Running app on Kubernetes

Now that you've tested the app locally, lets run this onkubernetes. First step towards that is to run docker tag to tag your image

$ docker image tag demoapp:latest rajpaljatin19/pythonflask-demoapp:latest

Now run docker push command to push your docker image to docker hub or any other image registry. For our example, i am using docker hub.

jatinrajpal@Jatins-MacBook-Air docker % docker push <docker_hub_userid>/pythonflask-demoapp:latest
The push refers to repository [docker.io/<docker_hub_userid>/pythonflask-demoapp]
de8bb64b3075: Pushed
0aaf8cc6a65a: Pushed
cf99cfa2e6a8: Pushed
cbb6f10d19ff: Mounted from library/python
26f80e5f8eac: Mounted from library/python
407a0715f2df: Mounted from library/python
ccd22ec8669c: Mounted from library/python
3bea4e7d7b00: Mounted from library/python
latest: digest: sha256:0499a50032a24be27e420f864422e63ebc1ea712a57ffe7a362b3b699bde339a size: 1995

(This step requires you to create the account creation on Docker hub. if you already have the account, replace <docker_hub_userid> with your docker account name in the command )

Now that you have pushed the image to docker hub, lets start our minikube instance. Minikube is the local version of kubernetes cluster that you can run on your system

jatinrajpal@Jatins-MacBook-Air ~ % minikube start
😄  minikube v1.25.2 on Darwin 13.3 (arm64)
✨  Using the docker driver based on existing profile
👍  Starting control plane node minikube in cluster minikube
🚜  Pulling base image ...
🔄  Restarting existing docker container for "minikube" ...
🐳  Preparing Kubernetes v1.23.3 on Docker 20.10.12 ...
    ▪ kubelet.housekeeping-interval=5m
🔎  Verifying Kubernetes components...
    ▪ Using image gcr.io/k8s-minikube/storage-provisioner:v5
🌟  Enabled addons: storage-provisioner, default-storageclass
🏄  Done! kubectl is now configured to use "minikube" cluster and "default" namespace by default

Then navigate to k8s_configs directory and run kubectl apply -f to your deployment YAML config file

jatinrajpal@Jatins-MacBook-Air docker % cd ../k8s_configs
jatinrajpal@Jatins-MacBook-Air k8s % kubectl apply -f deployment.yaml
deployment.apps/demoapp created
service/demoapp-svc created

Check the deployment and services created as per your YAML

jatinrajpal@Jatins-MacBook-Air k8s_deep_dive % kubectl get pods
NAME                      READY   STATUS    RESTARTS   AGE
demoapp-5b9b96569-dcrq7   1/1     Running   0          67m
demoapp-5b9b96569-k7rxd   1/1     Running   0          67m
demoapp-5b9b96569-p68p4   1/1     Running   0          67m

jatinrajpal@Jatins-MacBook-Air k8s_deep_dive % kubectl get deployment
NAME      READY   UP-TO-DATE   AVAILABLE   AGE 
demoapp   3/3          3        3          67m

jatinrajpal@Jatins-MacBook-Air k8s % kubectl get svc
NAME          TYPE           CLUSTER-IP       EXTERNAL-IP   PORT(S)          AGE
demoapp-svc   LoadBalancer   10.104.106.253   <pending>     6000:31494/TCP   3s
kubernetes    ClusterIP      10.96.0.1        <none>        443/TCP          2d

Run minikube tunnel. Tunnel creates a route to services deployed with type LoadBalancer and sets their Ingress to their ClusterIP

jatinrajpal@Jatins-MacBook-Air k8s % minikube tunnel
✅  Tunnel successfully started
📌  NOTE: Please do not close this terminal as this process must stay alive for the tunnel to be accessible ...
🏃  Starting tunnel for service demoapp-svc.

Once tunnel is started, you will notice EXTERNAL-IP will start coming in kubectl get svc (via seperate terminal window)

jatinrajpal@Jatins-MacBook-Air ~ % kubectl get svc
NAME          TYPE           CLUSTER-IP       EXTERNAL-IP   PORT(S)          AGE
demoapp-svc   LoadBalancer   10.104.106.253   127.0.0.1     6000:31494/TCP   11m
kubernetes    ClusterIP      10.96.0.1        <none>        443/TCP          2d
jatinrajpal@Jatins-MacBook-Air ~ %

You can then run curl to validate if your app is running or not. For our case, its very much up and running (via seperate terminal window)

jatinrajpal@Jatins-MacBook-Air ~ % curl -v "http://127.0.0.1:6000"
*   Trying 127.0.0.1:6000...
* Connected to 127.0.0.1 (127.0.0.1) port 6000 (#0)
> GET / HTTP/1.1
> Host: 127.0.0.1:6000
> User-Agent: curl/7.87.0
> Accept: */*
>
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< Server: Werkzeug/2.2.3 Python/3.9.16
< Date: Wed, 05 Apr 2023 08:57:15 GMT
< Content-Type: text/html; charset=utf-8
< Content-Length: 157
< Connection: close
<
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>FlaskBlog</title>
</head>
<body>
   <h1>Welcome to my Blog</h1>
</body>
* Closing connection 0
</html>%
jatinrajpal@Jatins-MacBook-Air ~ %

Once everything is done, clean your deployments and K8s minikube

jatinrajpal@Jatins-MacBook-Air app % kubectl delete deployment demoapp 
deployment.apps "demoapp" deleted
jatinrajpal@Jatins-MacBook-Air app % minikube delete
🔥  Deleting "minikube" in docker ...
🔥  Deleting container "minikube" ...
🔥  Removing /Users/jatinrajpal/.minikube/machines/minikube ...
💀  Removed all traces of the "minikube" cluster.

lalitpandey02 / k8s_deep_dive

k8s_deep_dive session

Running an app locally:

Running app via Docker

Running app on Kubernetes

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