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Converting from Docker-Compose
The first step will be to install kompose and convert our docker-compose.yml to kubernetes yaml files.
Install kompose
> brew install kompose
Startup without Converting
For simple docker-compose files, we can skip the steps pf converting and start up directly using kompose up.Start up directly
> kompose up
Exporting
Export docker-compose For more complicated docker-compose files, we will need to export and then modify the converted files.
> kompose convert
| Code Block |
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$ kompose convert WARN Volume mount on the host "/Users/john.mehan/projects/cloud/deployment/is-config/IND" isn't supported - ignoring path on the host INFO Kubernetes file "cloudservice-service.yaml" created INFO Kubernetes file "isservice-service.yaml" created INFO Kubernetes file "postgres-service.yaml" created INFO Kubernetes file "redis-service.yaml" created INFO Kubernetes file "cloudservice-deployment.yaml" created INFO Kubernetes file "isservice-deployment.yaml" created INFO Kubernetes file "isservice-claim0-persistentvolumeclaim.yaml" created INFO Kubernetes file "postgres-deployment.yaml" created INFO Kubernetes file "db-volume-persistentvolumeclaim.yaml" created INFO Kubernetes file "redis-deployment.yaml" created |
Create
...
Kubernetes pods in Cluster
We are using minkube for our cluster. Lets start by making sure it is running:
Might have to have minikube up and running for this to work
> minikube start
| Code Block |
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$ minikube start |
Using the yaml files created by kompose export, lets create our pods:
| Code Block |
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$ kubectl create -f cloudservice-service.yaml,isservice-service.yaml,postgres-service.yaml,redis-service.yaml,cloudservice-deployment.yaml,isservice-deployment.yaml,isservice-claim0-persistentvolumeclaim.yaml,postgres-deployment.yaml,db-volume-persistentvolumeclaim.yaml,redis-deployment.yaml
service/cloudservice created
service/isservice created
service/postgres created
service/redis created
deployment.extensions/cloudservice created
deployment.extensions/isservice created
persistentvolumeclaim/isservice-claim0 created
deployment.extensions/postgres created
persistentvolumeclaim/db-volume created
deployment.extensions/redis created
|
Expose a service
> kubectl expose deployment cloudservice --type=NodePort --name=cload-service
Pulling image from Docker Registry
Kubernetes will pull docker images from docker hub by default. For our own custom images, we will pull them from our local docker registry.
For this to work we need to
- create a secret in the cluster that holds our authorization token
- update our deployment yaml files to include this secret
- setup an ssh tunnel between our localhost running docker registry and our cluster (minikube)
Create a Secret in the cluster that holds your authorization token
> kubectl create secret docker-registry regcred --docker-server=<your-registry-server> --docker-username=<your-name> --docker-password=<your-pword> --docker-email=<your-email>
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kubectl create secret docker-registry regcred --docker-server=http://localhost:5000/ --docker-username=username --docker-password=password --docker-email=john.mehan@irdeto.com
secret/regcred created |
Revise deployment.yaml files
Add imagePullSecrets section to your deployment yaml files:
imagePullSecrets:
- name: regcred
example:
| Code Block |
|---|
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
...
spec:
replicas: 1
strategy:
type: Recreate
template:
metadata:
creationTimestamp: null
labels:
io.kompose.service: isservice
spec:
containers:
- image: localhost:5000/safa_is:0.1
name: isservice
ports:
- containerPort: 8080
|
| Code Block |
$ kubectl expose deployment cloudservice --type=NodePort --name=cload-service service/cload-service exposed $ kubectl get services NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE cload-service NodePort 10.105.166.253 <none> 8080:32696/TCP 5s cloudservice ClusterIP 10.107.194.8 <none> 80/TCP 37m hello-minikube NodePort 10.106.20.131 <none> 8080resources:32733/TCP 224d isservice {} ClusterIP 10.101.181.189tty: true <none> 7080/TCP 37m kubernetesvolumeMounts: ClusterIP - 10.96.0.1 <none> 443/TCP 224d postgresmountPath: /home/irdeto/CONF/ISF/IND ClusterIP name: 10.105.249.194is-volume <none> restartPolicy: Always 5432/TCP volumes: - name: 37mis-volume redis persistentVolumeClaim: ClusterIP 10.98.155.80 claimName: is-volume <none> imagePullSecrets: 6379/TCP - name: 37m |
Pulling image from Docker Registry
Create a Secret in the cluster that holds your authorization token
> kubectl create secret docker-registry regcred --docker-server=<your-registry-server> --docker-username=<your-name> --docker-password=<your-pword> --docker-email=<your-email>
regcred
status: {} |
Setup SSH Tunnel
We will setup an SSH Tunnel in order to allow kubernetes to pull images from our local docker registry.
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ssh -i ~/.minikube/machines/minikube/id_rsa docker@$(minikube ip) -R 5000:localhost:5000 |
| Code Block |
kubectl create secret docker-registry regcred --docker-server=http://localhost:5000/ --docker-username=username --docker-password=password --docker-email=john.mehan@irdeto.com
secret/regcred created |
References
| Reference | URL |
|---|---|
| Translate docker compose to Kubernetes | https://kubernetes.io/docs/tasks/configure-pod-container/translate-compose-kubernetes/ |
| Kotacoda Kubernetes Playground | https://www.katacoda.com/courses/kubernetes/playground |
| Pull an image from a Private Registry | https://kubernetes.io/docs/tasks/configure-pod-container/pull-image-private-registry/ |
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