Digital ocean Kubernetes + Django / PostgreSQL getting an database error inside cluster - django

Question

my app is inside a docker container and works perfectly fine in local host..but when i run this docker image in kubernetes cluster it gives me this error
conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
django.db.utils.OperationalError: could not translate host name "db" to address: Name or service not known
here is my database settings.py
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.postgresql',
'NAME': 'postgres',
'USER': 'postgres',
'HOST': 'db',
'PORT': 5432,
}
}
I deployed the image into kubernetes cluster with frontend.yml manifest file..it looks like this
frontend.yml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: dockersample-app
labels:
app: polls
spec:
replicas: 3
template:
metadata:
labels:
app: dcokersample-app
spec:
containers:
- name: dcokersample
image: mahesh61437/dockersample:v6
imagePullPolicy: Always
ports:
- containerPort: 8000
---service.yml
apiVersion: v1
kind: Service
metadata:
name: dockersample-app
labels:
app: dockersample-app
spec:
type: LoadBalancer
ports:
- port: 8000
targetPort: 8000
selector:
app: dockersample-app
here is my DOCKER File
FROM python:3
RUN apt-get update
EXPOSE 8000
ENV PYTHONUNBUFFERED 1
RUN mkdir /code
WORKDIR /code
COPY requirements.txt /code/
RUN pip install -r requirements.txt
COPY . /code/
CMD python manage.py runserver
kubectl get pod,svc,deployment,pvc,pv -o yaml
apiVersion: v1
items:
- apiVersion: v1
kind: Pod
metadata:
annotations:
cilium.io/identity: "63547"
creationTimestamp: "2019-02-14T09:49:39Z"
generateName: dockersample-app-557878d964-
labels:
app: dcokersample-app
pod-template-hash: 557878d964
name: dockersample-app-557878d964-fm94j
namespace: default
ownerReferences:
- apiVersion: apps/v1
blockOwnerDeletion: true
controller: true
kind: ReplicaSet
name: dockersample-app-557878d964
uid: d8b8a828-303d-11e9-94cc-9252dc3b5955
resourceVersion: "271350"
selfLink: /api/v1/namespaces/default/pods/dockersample-app-557878d964-fm94j
uid: d8bc708b-303d-11e9-94cc-9252dc3b5955
spec:
containers:
- image: mahesh61437/dockersample:v6
imagePullPolicy: Always
name: dcokersample
ports:
- containerPort: 8000
protocol: TCP
resources: {}
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
volumeMounts:
- mountPath: /var/run/secrets/kubernetes.io/serviceaccount
name: default-token-svb6z
readOnly: true
dnsPolicy: ClusterFirst
enableServiceLinks: true
nodeName: vibrant-ramanujan-8zmn
priority: 0
restartPolicy: Always
schedulerName: default-scheduler
securityContext: {}
serviceAccount: default
serviceAccountName: default
terminationGracePeriodSeconds: 30
tolerations:
- effect: NoExecute
key: node.kubernetes.io/not-ready
operator: Exists
tolerationSeconds: 300
- effect: NoExecute
key: node.kubernetes.io/unreachable
operator: Exists
tolerationSeconds: 300
volumes:
- name: default-token-svb6z
secret:
defaultMode: 420
secretName: default-token-svb6z
status:
conditions:
- lastProbeTime: null
lastTransitionTime: "2019-02-14T09:49:39Z"
status: "True"
type: Initialized
- lastProbeTime: null
lastTransitionTime: "2019-02-14T09:49:49Z"
status: "True"
type: Ready
- lastProbeTime: null
lastTransitionTime: "2019-02-14T09:49:49Z"
status: "True"
type: ContainersReady
- lastProbeTime: null
lastTransitionTime: "2019-02-14T09:49:39Z"
status: "True"
type: PodScheduled
containerStatuses:
- containerID: docker://d82ec6f089cc76e64e7ba68d56ba5c1263343c08929d648c9fef005d4a08488c
image: mahesh61437/dockersample:v6
imageID: docker-pullable://mahesh61437/dockersample#sha256:54aa303cc5534609a1b579718f192323fad9dd57bd92a2897cd64f110438c965
lastState: {}
name: dcokersample
ready: true
restartCount: 0
state:
running:
startedAt: "2019-02-14T09:49:49Z"
hostIP: 10.139.16.196
phase: Running
podIP: 10.244.1.64
qosClass: BestEffort
startTime: "2019-02-14T09:49:39Z"
- apiVersion: v1
kind: Pod
metadata:
annotations:
cilium.io/identity: "63547"
creationTimestamp: "2019-02-14T09:49:39Z"
generateName: dockersample-app-557878d964-
labels:
app: dcokersample-app
pod-template-hash: 557878d964
name: dockersample-app-557878d964-ftngl
namespace: default
ownerReferences:
- apiVersion: apps/v1
blockOwnerDeletion: true
controller: true
kind: ReplicaSet
name: dockersample-app-557878d964
uid: d8b8a828-303d-11e9-94cc-9252dc3b5955
resourceVersion: "271354"
selfLink: /api/v1/namespaces/default/pods/dockersample-app-557878d964-ftngl
uid: d8bdda66-303d-11e9-94cc-9252dc3b5955
spec:
containers:
- image: mahesh61437/dockersample:v6
imagePullPolicy: Always
name: dcokersample
ports:
- containerPort: 8000
protocol: TCP
resources: {}
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
volumeMounts:
- mountPath: /var/run/secrets/kubernetes.io/serviceaccount
name: default-token-svb6z
readOnly: true
dnsPolicy: ClusterFirst
enableServiceLinks: true
nodeName: vibrant-ramanujan-8zm3
priority: 0
restartPolicy: Always
schedulerName: default-scheduler
securityContext: {}
serviceAccount: default
serviceAccountName: default
terminationGracePeriodSeconds: 30
tolerations:
- effect: NoExecute
key: node.kubernetes.io/not-ready
operator: Exists
tolerationSeconds: 300
- effect: NoExecute
key: node.kubernetes.io/unreachable
operator: Exists
tolerationSeconds: 300
volumes:
- name: default-token-svb6z
secret:
defaultMode: 420
secretName: default-token-svb6z
status:
conditions:
- lastProbeTime: null
lastTransitionTime: "2019-02-14T09:49:39Z"
status: "True"
type: Initialized
- lastProbeTime: null
lastTransitionTime: "2019-02-14T09:49:49Z"
status: "True"
type: Ready
- lastProbeTime: null
lastTransitionTime: "2019-02-14T09:49:49Z"
status: "True"
type: ContainersReady
- lastProbeTime: null
lastTransitionTime: "2019-02-14T09:49:39Z"
status: "True"
type: PodScheduled
containerStatuses:
- containerID: docker://ef71c722fbcc70ceb96d929e983e22263cbc40a54fd666cf73cc0dd73c437cae
image: mahesh61437/dockersample:v6
imageID: docker-pullable://mahesh61437/dockersample#sha256:54aa303cc5534609a1b579718f192323fad9dd57bd92a2897cd64f110438c965
lastState: {}
name: dcokersample
ready: true
restartCount: 0
state:
running:
startedAt: "2019-02-14T09:49:48Z"
hostIP: 10.139.120.24
phase: Running
podIP: 10.244.2.187
qosClass: BestEffort
startTime: "2019-02-14T09:49:39Z"
- apiVersion: v1
kind: Pod
metadata:
annotations:
cilium.io/identity: "63547"
creationTimestamp: "2019-02-14T09:49:39Z"
generateName: dockersample-app-557878d964-
labels:
app: dcokersample-app
pod-template-hash: 557878d964
name: dockersample-app-557878d964-lq78m
namespace: default
ownerReferences:
- apiVersion: apps/v1
blockOwnerDeletion: true
controller: true
kind: ReplicaSet
name: dockersample-app-557878d964
uid: d8b8a828-303d-11e9-94cc-9252dc3b5955
resourceVersion: "271358"
selfLink: /api/v1/namespaces/default/pods/dockersample-app-557878d964-lq78m
uid: d8be0705-303d-11e9-94cc-9252dc3b5955
spec:
containers:
- image: mahesh61437/dockersample:v6
imagePullPolicy: Always
name: dcokersample
ports:
- containerPort: 8000
protocol: TCP
resources: {}
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
volumeMounts:
- mountPath: /var/run/secrets/kubernetes.io/serviceaccount
name: default-token-svb6z
readOnly: true
dnsPolicy: ClusterFirst
enableServiceLinks: true
nodeName: vibrant-ramanujan-8z79
priority: 0
restartPolicy: Always
schedulerName: default-scheduler
securityContext: {}
serviceAccount: default
serviceAccountName: default
terminationGracePeriodSeconds: 30
tolerations:
- effect: NoExecute
key: node.kubernetes.io/not-ready
operator: Exists
tolerationSeconds: 300
- effect: NoExecute
key: node.kubernetes.io/unreachable
operator: Exists
tolerationSeconds: 300
volumes:
- name: default-token-svb6z
secret:
defaultMode: 420
secretName: default-token-svb6z
status:
conditions:
- lastProbeTime: null
lastTransitionTime: "2019-02-14T09:49:39Z"
status: "True"
type: Initialized
- lastProbeTime: null
lastTransitionTime: "2019-02-14T09:49:50Z"
status: "True"
type: Ready
- lastProbeTime: null
lastTransitionTime: "2019-02-14T09:49:50Z"
status: "True"
type: ContainersReady
- lastProbeTime: null
lastTransitionTime: "2019-02-14T09:49:39Z"
status: "True"
type: PodScheduled
containerStatuses:
- containerID: docker://fa3c8f25b260b0e3c032907ff796b5e22bf0479646d457914de518c3c6180be0
image: mahesh61437/dockersample:v6
imageID: docker-pullable://mahesh61437/dockersample#sha256:54aa303cc5534609a1b579718f192323fad9dd57bd92a2897cd64f110438c965
lastState: {}
name: dcokersample
ready: true
restartCount: 0
state:
running:
startedAt: "2019-02-14T09:49:49Z"
hostIP: 10.139.16.250
phase: Running
podIP: 10.244.0.168
qosClass: BestEffort
startTime: "2019-02-14T09:49:39Z"
- apiVersion: v1
kind: Service
metadata:
annotations:
kubectl.kubernetes.io/last-applied-configuration: |
{"apiVersion":"v1","kind":"Service","metadata":{"annotations":{},"labels":{"app":"dockersample-app"},"name":"dockersample-app","namespace":"default"},"spec":{"ports":[{"port":8000,"targetPort":8000}],"selector":{"app":"dockersample-app"},"type":"LoadBalancer"}}
creationTimestamp: "2019-02-14T09:49:39Z"
labels:
app: dockersample-app
name: dockersample-app
namespace: default
resourceVersion: "271514"
selfLink: /api/v1/namespaces/default/services/dockersample-app
uid: d8c78f7a-303d-11e9-94cc-9252dc3b5955
spec:
clusterIP: 10.245.57.250
externalTrafficPolicy: Cluster
ports:
- nodePort: 32204
port: 8000
protocol: TCP
targetPort: 8000
selector:
app: dockersample-app
sessionAffinity: None
type: LoadBalancer
status:
loadBalancer:
ingress:
- ip: 174.138.123.199
- apiVersion: v1
kind: Service
metadata:
creationTimestamp: "2019-02-12T09:31:19Z"
labels:
component: apiserver
provider: kubernetes
name: kubernetes
namespace: default
resourceVersion: "6"
selfLink: /api/v1/namespaces/default/services/kubernetes
uid: f3f45187-2ea8-11e9-94cc-9252dc3b5955
spec:
clusterIP: 10.245.0.1
ports:
- name: https
port: 443
protocol: TCP
targetPort: 443
sessionAffinity: None
type: ClusterIP
status:
loadBalancer: {}
- apiVersion: extensions/v1beta1
kind: Deployment
metadata:
annotations:
deployment.kubernetes.io/revision: "1"
kubectl.kubernetes.io/last-applied-configuration: |
{"apiVersion":"extensions/v1beta1","kind":"Deployment","metadata":{"annotations":{},"labels":{"app":"polls"},"name":"dockersample-app","namespace":"default"},"spec":{"replicas":3,"template":{"metadata":{"labels":{"app":"dcokersample-app"}},"spec":{"containers":[{"image":"mahesh61437/dockersample:v6","imagePullPolicy":"Always","name":"dcokersample","ports":[{"containerPort":8000}]}]}}}}
creationTimestamp: "2019-02-14T09:49:39Z"
generation: 1
labels:
app: polls
name: dockersample-app
namespace: default
resourceVersion: "271360"
selfLink: /apis/extensions/v1beta1/namespaces/default/deployments/dockersample-app
uid: d8b79710-303d-11e9-94cc-9252dc3b5955
spec:
progressDeadlineSeconds: 2147483647
replicas: 3
revisionHistoryLimit: 2147483647
selector:
matchLabels:
app: dcokersample-app
strategy:
rollingUpdate:
maxSurge: 1
maxUnavailable: 1
type: RollingUpdate
template:
metadata:
creationTimestamp: null
labels:
app: dcokersample-app
spec:
containers:
- image: mahesh61437/dockersample:v6
imagePullPolicy: Always
name: dcokersample
ports:
- containerPort: 8000
protocol: TCP
resources: {}
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
dnsPolicy: ClusterFirst
restartPolicy: Always
schedulerName: default-scheduler
securityContext: {}
terminationGracePeriodSeconds: 30
status:
availableReplicas: 3
conditions:
- lastTransitionTime: "2019-02-14T09:49:49Z"
lastUpdateTime: "2019-02-14T09:49:49Z"
message: Deployment has minimum availability.
reason: MinimumReplicasAvailable
status: "True"
type: Available
observedGeneration: 1
readyReplicas: 3
replicas: 3
updatedReplicas: 3
- apiVersion: v1
kind: PersistentVolumeClaim
metadata:
annotations:
kubectl.kubernetes.io/last-applied-configuration: |
{"apiVersion":"v1","kind":"PersistentVolumeClaim","metadata":{"annotations":{},"labels":{"app":"postgres"},"name":"postgres-pv-claim","namespace":"default"},"spec":{"accessModes":["ReadWriteMany"],"resources":{"requests":{"storage":"5Gi"}},"storageClassName":"manual"}}
pv.kubernetes.io/bind-completed: "yes"
pv.kubernetes.io/bound-by-controller: "yes"
creationTimestamp: "2019-02-14T10:11:47Z"
finalizers:
- kubernetes.io/pvc-protection
labels:
app: postgres
name: postgres-pv-claim
namespace: default
resourceVersion: "273451"
selfLink: /api/v1/namespaces/default/persistentvolumeclaims/postgres-pv-claim
uid: f02728ee-3040-11e9-94cc-9252dc3b5955
spec:
accessModes:
- ReadWriteMany
dataSource: null
resources:
requests:
storage: 5Gi
storageClassName: manual
volumeMode: Filesystem
volumeName: postgres-pv-volume
status:
accessModes:
- ReadWriteMany
capacity:
storage: 5Gi
phase: Bound
- apiVersion: v1
kind: PersistentVolume
metadata:
annotations:
kubectl.kubernetes.io/last-applied-configuration: |
{"apiVersion":"v1","kind":"PersistentVolume","metadata":{"annotations":{},"labels":{"app":"postgres","type":"local"},"name":"postgres-pv-volume"},"spec":{"accessModes":["ReadWriteMany"],"capacity":{"storage":"5Gi"},"hostPath":{"path":"/mnt/data"},"storageClassName":"manual"}}
pv.kubernetes.io/bound-by-controller: "yes"
creationTimestamp: "2019-02-14T10:11:47Z"
finalizers:
- kubernetes.io/pv-protection
labels:
app: postgres
type: local
name: postgres-pv-volume
resourceVersion: "273449"
selfLink: /api/v1/persistentvolumes/postgres-pv-volume
uid: f01f5beb-3040-11e9-94cc-9252dc3b5955
spec:
accessModes:
- ReadWriteMany
capacity:
storage: 5Gi
claimRef:
apiVersion: v1
kind: PersistentVolumeClaim
name: postgres-pv-claim
namespace: default
resourceVersion: "273446"
uid: f02728ee-3040-11e9-94cc-9252dc3b5955
hostPath:
path: /mnt/data
type: ""
persistentVolumeReclaimPolicy: Retain
storageClassName: manual
volumeMode: Filesystem
status:
phase: Bound
kind: List
metadata:
resourceVersion: ""
selfLink: ""
I cant figure out what I must do now. If you think you can suggest better in my code me something please leave a comment.

Answer 1

It's missing the database deployement and service (optional but highly recommended PersistentVolumeClaim).
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: db-deployment
labels:
app: db-deployment
spec:
replicas: 1
template:
metadata:
labels:
app: db
spec:
containers:
- image: postgres:9.4
name: db
ports:
- containerPort: 5432
volumeMounts:
- name: postgres-db-data
mountPath: /var/lib/postgresql
volumes:
- name: postgres-db-data
persistentVolumeClaim:
claimName: db-data
---
apiVersion: v1
kind: Service
metadata:
name: db
labels:
name: db
spec:
ports:
- name: db
port: 5432
selector:
app: db-deployment
---
apiVersion: "v1"
kind: "PersistentVolumeClaim"
metadata:
name: "db-data"
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 20Gi
storageClassName: "your storage class"