I am using kubernetes on a single machine for testing, I have built a custom image from the nginx docker image, but when I try to use the image in kubernetes I get an image pull error?????
MY POD YAML
kind: Pod
apiVersion: v1
metadata:
name: yumserver
labels:
name: frontendhttp
spec:
containers:
- name: myfrontend
image: my/nginx:latest
ports:
- containerPort: 80
name: "http-server"
volumeMounts:
- mountPath: "/usr/share/nginx/html"
name: mypd
imagePullSecrets:
- name: myregistrykey
volumes:
- name: mypd
persistentVolumeClaim:
claimName: myclaim-1
MY KUBERNETES COMMAND
kubectl create -f pod-yumserver.yaml
THE ERROR
kubectl describe pod yumserver
Name: yumserver
Namespace: default
Image(s): my/nginx:latest
Node: 127.0.0.1/127.0.0.1
Start Time: Tue, 26 Apr 2016 16:31:42 +0100
Labels: name=frontendhttp
Status: Pending
Reason:
Message:
IP: 172.17.0.2
Controllers: <none>
Containers:
myfrontend:
Container ID:
Image: my/nginx:latest
Image ID:
QoS Tier:
memory: BestEffort
cpu: BestEffort
State: Waiting
Reason: ErrImagePull
Ready: False
Restart Count: 0
Environment Variables:
Conditions:
Type Status
Ready False
Volumes:
mypd:
Type: PersistentVolumeClaim (a reference to a PersistentVolumeClaim in the same namespace)
ClaimName: myclaim-1
ReadOnly: false
default-token-64w08:
Type: Secret (a secret that should populate this volume)
SecretName: default-token-64w08
Events:
FirstSeen LastSeen Count From SubobjectPath Type Reason Message
--------- -------- ----- ---- ------------- -------- ------ -------
13s 13s 1 {default-scheduler } Normal Scheduled Successfully assigned yumserver to 127.0.0.1
13s 13s 1 {kubelet 127.0.0.1} Warning MissingClusterDNS kubelet does not have ClusterDNS IP configured and cannot create Pod using "ClusterFirst" policy. Falling back to DNSDefault policy.
12s 12s 1 {kubelet 127.0.0.1} spec.containers{myfrontend} Normal Pulling pulling image "my/nginx:latest"
8s 8s 1 {kubelet 127.0.0.1} spec.containers{myfrontend} Warning Failed Failed to pull image "my/nginx:latest": Error: image my/nginx:latest not found
8s 8s 1 {kubelet 127.0.0.1} Warning FailedSync Error syncing pod, skipping: failed to "StartContainer" for "myfrontend" with ErrImagePull: "Error: image my/nginx:latest not found"
Make sure that your "Kubernetes Context" in Docker Desktop is actually a "docker-desktop" (i.e. not a remote cluster).
(Right click on Docker icon, then select "Kubernetes" in menu)
All you need to do is just do a docker build from your dockerfile, or get all the images on the nodes of your cluster, do a suitable docker tag and create the manifest.
Kubernetes doesn't directly pull from the registry. First it searches for the image on local storage and then docker registry.
Pull latest nginx image
docker pull nginx
docker tag nginx:latest test:test8970
Create a deployment kubectl run test --image=test:test8970
It won't go to docker registry to pull the image. It will bring up the pod instantly.
And if image is not present on local machine it will try to pull from docker registry and fail with ErrImagePull error.
Also if you change the imagePullPolicy: Never. It will never look for the registry to pull the image and will fail if image is not found with error ErrImageNeverPull.
kind: Deployment
metadata:
labels:
run: test
name: test
spec:
replicas: 1
selector:
matchLabels:
run: test
template:
metadata:
creationTimestamp: null
labels:
run: test
spec:
containers:
- image: test:test8070
name: test
imagePullPolicy: Never
So you have the image on your machine aready. It still tries to pull the image from Docker Hub, however, which is likely not what you want on your single-machine setup. This is happening because the latest tag sets the imagePullPolicy to Always implicitly. You can try setting it to IfNotPresent explicitly or change to a tag other than latest. – Timo Reimann Apr 28 at 7:16
For some reason Timo Reimann did only post this above as a comment, but it definitely should be the official answer to this question, so I'm posting it again.
Run eval $(minikube docker-env) before building your image.
Full answer here: https://stackoverflow.com/a/40150867
The easiest way to further analysis ErrImagePull
problems is to ssh into the node and try to pull the image manually by doing docker pull my/nginx:latest
. I've never set up Kubernetes on a single machine but could imagine that the Docker daemon isn't reachable from the node for some reason. A handish pull attempt should provide more information.
This should work irrespective of whether you are using minikube or not :
1) Start a local registry container:
docker run -d -p 5000:5000 --restart=always --name registry registry:2
2) Do docker images
to find out the REPOSITORY and TAG of your local image. Then create a new tag for your local image :
docker tag <local-image-repository>:<local-image-tag> localhost:5000/<local-image-name>
If TAG for your local image is <none>
, you can simply do:
docker tag <local-image-repository> localhost:5000/<local-image-name>
3) Push to local registry :
docker push localhost:5000/<local-image-name>
This will automatically add the latest
tag to localhost:5000/<local-image-name>
. You can check again by doing docker images
.
4) In your yaml file, set imagePullPolicy
to IfNotPresent
:
...
spec:
containers:
- name: <name>
image: localhost:5000/<local-image-name>
imagePullPolicy: IfNotPresent
...
That's it. Now your ImagePullError should be resolved.
Are you using minikube on linux? You need to install docker ( I think), but you don't need to start it. Minikube will do that. Try using the KVM driver with this command:
minikube start --vm-driver kvm
Then run the eval $(minikube docker-env)
command to make sure you use the minikube docker environment. build your container with a tag build -t mycontainername:version .
if you then type docker ps
you should see a bunch of minikube containers already running. kvm utils are probably already on your machine, but they can be installed like this on centos/rhel:
yum install qemu-kvm qemu-img virt-manager libvirt libvirt-python