Django application deployment in kubernetes
To get started with kubernetes in local environment use Microk8s. Go through the microk8s setup documentation and setup it.
Adding alias to "microk8s.kubectl" to "k8s"
Open ~/.bashrc and below line at the end of the file.
alias k8s="microk8s.kubectl"Now, clone this repo using below commands
git clone git@github.com:AnjaneyuluBatta505/kubernetes_django.git
Let's start the deployment of the django application and other apps like redis, postgres, flower, etc.
Setting up postgres service
In the postgres we have 4 yaml configuration files.
- secrets.yaml - Useful when using secret env vaibles in the apps
- volume.yaml - Persistent Volume for Postgres database
- volume_claim.yaml - This claim lets our deployment application store its data in an external location, so that if one of the application’s containers fails, it can be replaced with a new container and continue accessing its data stored externally, as though an outage never occurred.
- deployment.yaml - Deployment to start the application containers
- service.yaml - Allows other apps to comminicate with it's related deployment(i.e pods/containers)
Now, create above objects in kubernetes using below commands
k8s apply -f kubernetes/postgres/secrets.yaml
k8s apply -f kubernetes/postgres/volume.yaml
k8s apply -f kubernetes/postgres/volume_claim.yaml
k8s apply -f kubernetes/postgres/deployment.yaml
k8s apply -f kubernetes/postgres/service.yaml
We have successfully created the postgres service in k8s(i.e kubernetes cluster).
Setting up redis service
In the redis we have 2 yaml configuration files.
To setup the redis service in k8s execute the below commands
k8s apply -f kubernetes/redis/deployment.yaml
k8s apply -f kubernetes/redis/service.yaml
Setting up django app
In django app we have 3 yaml configuration files.
To setup the django app in k8s execute the below commands
k8s apply -f kubernetes/django/job-migration.yaml
k8s apply -f kubernetes/django/deployment.yaml
k8s apply -f kubernetes/django/service.yaml
Setting up celery app
In celery app we have 2 yaml configuration files.
To setup the django app in k8s execute the below commands
k8s apply -f kubernetes/celery/beat-deployment.yaml
k8s apply -f kubernetes/celery/worker-deployment.yaml
Setting up flower app
In flower app we have 2 yaml configuration files.
To setup the django app in k8s execute the below commands
k8s apply -f kubernetes/flower/deployment.yaml
k8s apply -f kubernetes/flower/service.yaml
How to debug the pods for errors if any failures occurs ?
$ k8s get po
NAME READY STATUS RESTARTS AGE
celery-beat-75b5f954-m2pzj 1/1 Running 0 64m
celery-worker-56fc7b88f5-shd87 1/1 Running 0 61m
django-688f76f576-kt4h6 1/1 Error 0 60m
django-migrations-mhng7 0/1 Completed 0 59m
flower-77bf99c799-9drnp 1/1 Running 87 20h
postgres-76dc76ffbb-hzmdc 1/1 Running 2 23h
redis-76f6f4857b-srxlw 1/1 Running 1 20h
We can debug the pod failure using command k8s logs <pod name>.
Sometimes k8s describe <name of k8s object>
To access the django app in our local browser
$ k8s get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
django-service NodePort 10.152.183.146 <none> 8000:32693/TCP 21h
flower-service NodePort 10.152.183.170 <none> 5555:30675/TCP 21h
kubernetes ClusterIP 10.152.183.1 <none> 443/TCP 25h
postgres-service ClusterIP 10.152.183.151 <none> 5432/TCP 24h
redis-service ClusterIP 10.152.183.89 <none> 6379/TCP 21h
Visit url "10.152.183.146:8000" (i.e CLUSTER-IP:PORT). It's just for testing.