How to use Kubernetes Secret to pull a private docker image from docker hub?

Question

I'm trying to run my kuberntes app using minikube on ubuntu20.04 and applied a secret to pull a private docker image from docker hub, but it doesn't seem to work correctly.

Failed to pull image "xxx/node-graphql:latest": rpc error: code = Unknown desc = Error response from daemon: pull access denied for xxx/node-graphql, repository does not exist or may require 'docker login': denied: requested access to the resource is denied

Here's the secret generated by

kubectl create secret generic regcred \                     
    --from-file=.dockerconfigjson=<pathtofile>.docker/config.json \
    --type=kubernetes.io/dockerconfigjson

And here's the secret yaml file I have created

apiVersion: v1
data:
  .dockerconfigjson: xxx9tRXpNakZCSTBBaFFRPT0iCgkJfQoJfQp9
kind: Secret
metadata:
  name: node-graphql-secret
  uid: xxx-2e18-44eb-9719-xxx
type: kubernetes.io/dockerconfigjson

Did anyone try to pull a private docker image into Kubernetes using a secret? Any kind of help would be appreciated. Thank you!

Answer 1

I managed to add the secrets config in the following steps.

First, you need to login to docker hub using:

docker login

Next, you create a k8s secret running:

kubectl create secret generic <your-secret-name>\\n    --from-file=.dockerconfigjson=<pathtoyourdockerconfigfile>.docker/config.json \\n    --type=kubernetes.io/dockerconfigjson

And then get the secret in yaml format

kubectl get secret -o yaml

It should look like this:

apiVersion: v1
items:
- apiVersion: v1
  data:
    .dockerconfigjson: xxxewoJImF1dGhzIjogewoJCSJodHRwczovL2luZGV4LmRvY2tl
  kind: Secret
  metadata:
    creationTimestamp: "2022-10-27T23:06:01Z"
    name: <your-secret-name>
    namespace: default
    resourceVersion: "513"
    uid: xxxx-0f12-4beb-be41-xxx
  type: kubernetes.io/dockerconfigjson
kind: List
metadata:
  resourceVersion: ""

And I have copied the content for the secret in the secret yaml file:

apiVersion: v1
data:
  .dockerconfigjson: xxxewoJImF1dGhzIjogewoJCSJodHRwczovL2luZGV4LmRvY2tlci
kind: Secret
metadata:
  creationTimestamp: "2022-10-27T23:06:01Z"
  name: <your-secret-name>
  namespace: default
  resourceVersion: "513"
  uid: xxx-0f12-4beb-be41-xxx
type: kubernetes.io/dockerconfigjson

It works! This is a simple approach to using Secret to pull a private docker image for K8s.

As a side note, to apply the secret, run kubectl apply -f secret.yml

Hope it helps