I am trying to prepare a dev environment for my team, so we can develop, create and deploy with the same (or next to it) environment.
Getting a Kubernetes cluster running locally through http://kubernetes.io/v1.0/docs/getting-started-guides/docker.html was nice and easy. Then I could use kubectl to run containers and services for my application.
However, at each start, the IP addresses of the services will be different from each other. This is a problem if your code should use them. In Google Container Engine kube DNS means that you can access the service by name. This means that code that uses the service can remain constant between deployments.
Now I know that we could combine IP and PORT through environment variables, but I wanted to have the same setting as possible.
So, I followed some instructions found in different places, both here and in the Kubernet repository, for example this .
Of course, with a little editing of the yml files, KubeDNS starts up.
But nslookup on kubernetes.default fails. The DNS health check also fails (because it cannot resolve the test search), and the instance shuts down and restarts.
Running kubectl cluster-infoleads to:
Kubernetes master is running at http:
KubeDNS is running at http:
So all is well. However, the defeat of this endpoint leads to:
{
kind: "Status",
apiVersion: "v1",
metadata: { },
status: "Failure",
message: "no endpoints available for "kube-dns"",
code: 500
}
I am now at a loss and I know that this is something obvious or easy to fix, because it seems that everyone is working. This is how I start the cluster and DNS.
docker run --net=host \
-d gcr.io/google_containers/etcd:2.0.12 /usr/local/bin/etcd \
--addr=127.0.0.1:4001 --bind-addr=0.0.0.0:4001 --data-dir=/var/etcd/data
docker run \
--volume=/:/rootfs:ro \
--volume=/sys:/sys:ro \
--volume=/dev:/dev \
--volume=/var/lib/docker/:/var/lib/docker:ro \
--volume=/var/lib/kubelet/:/var/lib/kubelet:rw \
--volume=/var/run:/var/run:rw \
--net=host \
--privileged=true \
-d \
gcr.io/google_containers/hyperkube:v1.0.6 \
/hyperkube kubelet --containerized --hostname-override="127.0.0.1" \
--address="0.0.0.0" --api-servers=http://localhost:8080 \
--config=/etc/kubernetes/manifests \
--cluster_dns=10.0.0.10 --cluster_domain=cluster.local
docker run -d --net=host --privileged gcr.io/google_containers/hyperkube:v1.0.6 \
/hyperkube proxy --master=http://127.0.0.1:8080 --v=2
machine=default; ssh -i ~/.docker/machine/machines/$machine/id_rsa docker@$(docker-machine ip $machine) -L 8080:localhost:8080
, kubectl . . dns.
DNS rc ,
apiVersion: v1
kind: ReplicationController
metadata:
name: kube-dns-v9
namespace: kube-system
labels:
k8s-app: kube-dns
version: v9
kubernetes.io/cluster-service: "true"
spec:
replicas: 1
selector:
k8s-app: kube-dns
version: v9
template:
metadata:
labels:
k8s-app: kube-dns
version: v9
kubernetes.io/cluster-service: "true"
spec:
containers:
- name: etcd
image: gcr.io/google_containers/etcd:2.0.9
resources:
limits:
cpu: 100m
memory: 50Mi
command:
- /usr/local/bin/etcd
- -data-dir
- /var/etcd/data
- -listen-client-urls
- http://127.0.0.1:2379,http://127.0.0.1:4001
- -advertise-client-urls
- http://127.0.0.1:2379,http://127.0.0.1:4001
- -initial-cluster-token
- skydns-etcd
volumeMounts:
- name: etcd-storage
mountPath: /var/etcd/data
- name: kube2sky
image: gcr.io/google_containers/kube2sky:1.11
resources:
limits:
cpu: 100m
memory: 50Mi
args:
- -domain=cluster.local
- name: skydns
image: gcr.io/google_containers/skydns:2015-10-13-8c72f8c
resources:
limits:
cpu: 100m
memory: 50Mi
args:
- -machines=http://localhost:4001
- -addr=0.0.0.0:53
- -ns-rotate=false
- -domain=cluster.local
ports:
- containerPort: 53
name: dns
protocol: UDP
- containerPort: 53
name: dns-tcp
protocol: TCP
livenessProbe:
httpGet:
path: /healthz
port: 8080
scheme: HTTP
initialDelaySeconds: 30
timeoutSeconds: 5
readinessProbe:
httpGet:
path: /healthz
port: 8080
scheme: HTTP
initialDelaySeconds: 1
timeoutSeconds: 5
- name: healthz
image: gcr.io/google_containers/exechealthz:1.0
resources:
limits:
cpu: 10m
memory: 20Mi
args:
- -cmd=nslookup kubernetes.default.svc.cluster.local 127.0.0.1 >/dev/null
- -port=8080
ports:
- containerPort: 8080
protocol: TCP
volumes:
- name: etcd-storage
emptyDir: {}
dnsPolicy: Default # Don't use cluster DNS.
( repo)
apiVersion: v1
kind: Service
metadata:
name: kube-dns
namespace: kube-system
labels:
k8s-app: kube-dns
kubernetes.io/cluster-service: "true"
kubernetes.io/name: "KubeDNS"
spec:
selector:
k8s-app: kube-dns
clusterIP: 10.0.0.10
ports:
- name: dns
port: 53
protocol: UDP
- name: dns-tcp
port: 53
protocol: TCP
, SO, clusterIP - , master, ip -. , - , . -, ?
!
UPDATE
GitHub. , .
GitHub , . , ( -, ).
, , , IP- /. api .
docker exec 49705c38846a echo $(curl http://0.0.0.0:8080/api/v1/services?labels=)
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 908 100 908 0 0 314k 0 --:--:-- --:--:-- --:--:-- 443k
{ "kind": "ServiceList", "apiVersion": "v1", "metadata": { "selfLink": "/api/v1/services", "resourceVersion": "948" }, "items": [ { "metadata": { "name": "kubernetes", "namespace": "default", "selfLink": "/api/v1/namespaces/default/services/kubernetes", "uid": "369a9307-796e-11e5-87de-7a0704d1fdad", "resourceVersion": "6", "creationTimestamp": "2015-10-23T10:09:57Z", "labels": { "component": "apiserver", "provider": "kubernetes" } }, "spec": { "ports": [ { "protocol": "TCP", "port": 443, "targetPort": 443, "nodePort": 0 } ], "clusterIP": "10.0.0.1", "type": "ClusterIP", "sessionAffinity": "None" }, "status": { "loadBalancer": {} } } ] }
, JSON kube2Sky!?
Failed to list *api.Service: couldn't get version/kind; json parse error: invalid character '<' looking for beginning of value
Failed to list *api.Endpoints: couldn't get version/kind; json parse error: invalid character '<' looking for beginning of value