Tag Archives: kubernetes

Microk8s and Wagtail Bakery

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Playing around with Kubernetes? Just found the easy way to test it using Microk8s.io MicroK8s make you focus on building and testing your application to run on K8s. It’s best tool to test microservices locally.

To start running a Wagtail CMS a Python CMS, we selected the bakery demo.

Here we have documented how to run the demo using Microk8s.
Assuming you have run microk8s on you local machine, start creating the Docker image. Another great tool to convert docker-compose file to kubernetes is to use the kompose.io.

$ docker build . -t bakery_app2:local
$ docker save bakery_app2 > bakeryapp.tar

$ microk8s.ctr  -n k8s.io image import bakeryapp.tar
$ microk8s.ctr -n k8s.io images list | grep bakery

See the deployment/app-deployment.yaml it is using the local image bakerydemo_app:latest Then start deploying the yaml files using microk8s.kubectl apply -f command.

Sample *.yaml files are inside directory deployment or generate it using the command below:

$ cd deployment
$ kompose convert -f ../docker-compose.yml

Here is Wagtails Demo running inside microk8s screenshots.

Making it easier to migrate to use K8 can be on Google or AWS.

Kubernetes using Amazon EKS

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This is a run through simple demonstration of deploying application using Kubectl and Kubernetes using Amazon EKS.
Kubernetes aims to run containers across many different machines and scaling up or down by adding or removing containers when demand changes.

I’ts been a while since I posted on this blog. So here it goes. 😀

I. Prerequisites

Before we can start we need to setup some accounts and command-line utilities:

1. AWS Account
2. EC2 Key Pair — Create an EC2 Key Pair if you don’t already have one.
3. AWS CLI — Amazon EKS requires at least version 1.15.32 of the AWS CLI
4. Document for EKS: https://docs.aws.amazon.com/eks/latest/userguide/getting-started.html

II. Setup and Configure kubectl for Amazon EKS

$ curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -
$ sudo touch /etc/apt/sources.list.d/kubernetes.list 
$ echo "deb http://apt.kubernetes.io/ kubernetes-xenial main" | sudo tee -a /etc/apt/sources.list.d/kubernetes.list
$ sudo apt-get update
$ sudo apt-get install -y kubectl

$ aws eks update-kubeconfig --name so_cluster

III. Installing aws-iam-authenticator:

$ go get -u -v github.com/kubernetes-sigs/aws-iam-authenticator/cmd/aws-iam-authenticator
$ export PATH=$HOME/go/bin:$PATH && echo 'export PATH=$HOME/go/bin:$PATH' >> ~/.bashrc

IV. Create Worker Nodes: Common Problems

1. The cluster-name should be equal to the cluster created on the Cloud Formation parameter.

2. The NodeInstanceRole value from Cloud Formation Stack Output and placing it at aws-auth-cm.yaml rolearn as value.

Filename: aws-auth-cm.yaml

apiVersion: v1
kind: ConfigMap
metadata:
  name: aws-auth
  namespace: kube-system
data:
  mapRoles: |
    - rolearn: <ARN of instance role (not instance profile)>
      username: system:node:{{EC2PrivateDNSName}}
      groups:
        - system:bootstrappers
        - system:nodes

When everything is up and working good, we should be able to see it running:

$ kubectl get nodes 
NAME                           STATUS   ROLES    AGE   VERSION
ip-172-30-0-28.ec2.internal    Ready    <none>   6m    v1.11.5
ip-172-30-4-123.ec2.internal   Ready    <none>   6m    v1.11.5

$ kubectl get svc --all-namespaces
NAMESPACE     NAME         TYPE        CLUSTER-IP    EXTERNAL-IP   PORT(S)         AGE
default       kubernetes   ClusterIP   10.100.0.1    <none>        443/TCP         32m
kube-system   kube-dns     ClusterIP   10.100.0.10   <none>        53/UDP,53/TCP   32m

Get some Nginx running on this cluster, create replica:

$ kubectl create deployment nginx --image=nginx
deployment.apps/nginx created

$ kubectl scale deployment --replicas 2 nginx

$ kubectl get pods --all-namespaces
NAMESPACE     NAME                       READY   STATUS    RESTARTS   AGE
default       nginx-78f5d695bd-8qvmx     1/1     Running   0          28s
default       nginx-78f5d695bd-fq6dc     1/1     Running   0          4m
kube-system   aws-node-wc7sc             1/1     Running   0          16m
kube-system   aws-node-xjrqh             1/1     Running   0          16m
kube-system   coredns-7bcbfc4774-5psht   1/1     Running   0          41m
kube-system   coredns-7bcbfc4774-wrmwx   1/1     Running   0          41m
kube-system   kube-proxy-522bd           1/1     Running   0          16m
kube-system   kube-proxy-jw2l9           1/1     Running   0          16m

Expose Nginx to the public: 

$ kubectl expose deployment nginx --port=80 --type=LoadBalancer
service/nginx exposed

$ kubectl get svc 
NAME         TYPE           CLUSTER-IP      EXTERNAL-IP                                                              PORT(S)        AGE
kubernetes   ClusterIP      10.100.0.1      <none>                                                                   443/TCP        53m
nginx        LoadBalancer   10.100.163.52   ac198ac591ed911e9be5812b977585b7-343561898.us-east-1.elb.amazonaws.com   80:32267/TCP   4m

The EXTERNAL IP provided is an URL where we can map as CNAME to our Route53 or DNS. We can check by hitting the URL too:

In some cases the deployment and services are bundled as JSON like this one on the sample guestbook, we can run it like: 

$ kubectl apply -f https://raw.githubusercontent.com/kubernetes/examples/master/guestbook/all-in-one/guestbook-all-in-one.yaml
service/redis-master created
deployment.apps/redis-master created
service/redis-slave created
deployment.apps/redis-slave created
service/frontend created
deployment.apps/frontend created

$ kubectl get svc
NAME           TYPE           CLUSTER-IP      EXTERNAL-IP                                                              PORT(S)        AGE
frontend       ClusterIP      10.100.94.40    <none>                                                                   80/TCP         1m
kubernetes     ClusterIP      10.100.0.1      <none>                                                                   443/TCP        1h
nginx          LoadBalancer   10.100.163.52   ac198ac591ed911e9be5812b977585b7-343561898.us-east-1.elb.amazonaws.com   80:32267/TCP   18m
redis-master   ClusterIP      10.100.36.121   <none>                                                                   6379/TCP       1m
redis-slave    ClusterIP      10.100.168.28   <none>                                                                   6379/TCP       1m

Oops, there we can’t access the guestbook publicly. We need to patch because I forgot to uncomment the type=Loadbalancer, but we can easily create a patch file of that service and do the command below: 

$ kubectl patch svc frontend --patch "$(cat frontend_service.patch)"
service/frontend patched

$kubectl get svc
NAME           TYPE           CLUSTER-IP      EXTERNAL-IP                                                               PORT(S)        AGE
frontend       LoadBalancer   10.100.94.40    a395b01401edc11e9b7f40eb3bd0ef0f-1905156859.us-east-1.elb.amazonaws.com   80:32584/TCP   8m
kubernetes     ClusterIP      10.100.0.1      <none>                                                                    443/TCP        1h
nginx          LoadBalancer   10.100.163.52   ac198ac591ed911e9be5812b977585b7-343561898.us-east-1.elb.amazonaws.com    80:32267/TCP   25m
redis-master   ClusterIP      10.100.36.121   <none>                                                                    6379/TCP       8m
redis-slave    ClusterIP      10.100.168.28   <none>                                                                    6379/TCP       8m

Yeah so here it goes our Guestbook.

Finally, if we want to see how the dashboard looks like, we can view that too by applying the dashboard json files and running kubectl proxy. Here’s the snapshot of the dashboard.

Go fire up Dockerized apps using Kubernetes and if you need a Kubernets guy? Please reach out. 🙂