I'm trying to write a go template that extracts the value of the load balancer. Using --go-template={{status.loadBalancer.ingress}} returns [map[hostname:GUID.us-west-2.elb.amazonaws.com]]% When I add .hostname to the template I get an error saying, "can't evaluate field hostname in type interface {}". I've tried using the range keyword, but I can't seem to get the syntax right.
{
"apiVersion": "v1",
"kind": "Service",
"metadata": {
"creationTimestamp": "2018-07-30T17:22:12Z",
"labels": {
"run": "nginx"
},
"name": "nginx-http",
"namespace": "jx",
"resourceVersion": "495789",
"selfLink": "/api/v1/namespaces/jx/services/nginx-http",
"uid": "18aea6e2-941d-11e8-9c8a-0aae2cf24842"
},
"spec": {
"clusterIP": "10.100.92.49",
"externalTrafficPolicy": "Cluster",
"ports": [
{
"nodePort": 31032,
"port": 80,
"protocol": "TCP",
"targetPort": 8080
}
],
"selector": {
"run": "nginx"
},
"sessionAffinity": "None",
"type": "LoadBalancer"
},
"status": {
"loadBalancer": {
"ingress": [
{
"hostname": "GUID.us-west-2.elb.amazonaws.com"
}
]
}
}
}
As you can see from the JSON, the ingress element is an array. You can use the template function index to grab this array element.
Try:
kubectl get svc <name> -o=go-template --template='{{(index .status.loadBalancer.ingress 0 ).hostname}}'
This is assuming of course that you're only provisioning a single loadbalancer, if you have multiple, you'll have to use range
try this:
kubectl get svc <name> -o go-template='{{range .items}}{{range .status.loadBalancer.ingress}}{{.hostname}}{{printf "\n"}}{{end}}{{end}}'
Related
With the below yml file:
apiVersion: v1
kind: Pod
metadata:
name: my-nginx
spec:
containers:
- name: my-nginx
image: nginx:alpine
On running kubectl create -f nginx.pod.yml --save-config, then as per the documentation: If true, the configuration of current object will be saved in its annotation.
Where exactly is this annotation saved? How to view this annotation?
Below command would print all the annotations present in the pod my-nginx:
kubectl get pod my-nginx -o jsonpath='{.metadata.annotations}'
Under kubectl.kubernetes.io/last-applied-configuration of the above output, your configuration used is stored.
Here is an example showing the usage:
Original manifest for my deployment:
apiVersion: apps/v1
kind: Deployment
metadata:
creationTimestamp: null
labels:
app: my-deploy
name: my-deploy
spec:
replicas: 1
selector:
matchLabels:
app: my-deploy
strategy: {}
template:
metadata:
creationTimestamp: null
labels:
app: my-deploy
spec:
containers:
- image: nginx
name: nginx
resources: {}
status: {}
Created the deployment as follow:
k create -f x.yml --save-config
deployment.apps/my-deploy created
kubectl get deployments.apps my-deploy -o jsonpath='{.metadata.annotations.kubectl\.kubernetes\.io\/last-applied-configuration}' |jq .
{
"apiVersion": "apps/v1",
"kind": "Deployment",
"metadata": {
"annotations": {},
"creationTimestamp": null,
"labels": {
"app": "my-deploy"
},
"name": "my-deploy",
"namespace": "default"
},
"spec": {
"replicas": 1,
"selector": {
"matchLabels": {
"app": "my-deploy"
}
},
"strategy": {},
"template": {
"metadata": {
"creationTimestamp": null,
"labels": {
"app": "my-deploy"
}
},
"spec": {
"containers": [
{
"image": "nginx",
"name": "nginx",
"resources": {}
}
]
}
}
},
"status": {}
}
kubectl get deployments.apps my-deploy -o jsonpath='{.spec.template.spec.containers[*].image}'
nginx
Now some user came and changed the image on nginx from nginx to httpd, using imperative commands.
k set image deployment/my-deploy nginx=httpd --record
deployment.apps/my-deploy image updated
kubectl get deployments.apps my-deploy -o jsonpath='{.spec.template.spec.containers[*].image}'
httpd
However, we can check that the last applied declarative configuration is not updated.
kubectl get deployments.apps my-deploy -o jsonpath='{.metadata.annotations.kubectl\.kubernetes\.io\/last-applied-configuration}' |jq .
{
"apiVersion": "apps/v1",
"kind": "Deployment",
"metadata": {
"annotations": {},
"creationTimestamp": null,
"labels": {
"app": "my-deploy"
},
"name": "my-deploy",
"namespace": "default"
},
"spec": {
"replicas": 1,
"selector": {
"matchLabels": {
"app": "my-deploy"
}
},
"strategy": {},
"template": {
"metadata": {
"creationTimestamp": null,
"labels": {
"app": "my-deploy"
}
},
"spec": {
"containers": [
{
"image": "nginx",
"name": "nginx",
"resources": {}
}
]
}
}
},
"status": {}
}
Now, change the image name in the original manifest file from nginx to flask, then do kubectl apply(a declarative command)
kubectl apply -f orig.yml
deployment.apps/my-deploy configured
kubectl get deployments.apps my-deploy -o jsonpath='{.spec.template.spec.containers[*].image}'
flask
Now check the last applied configuration annotation, this would have flask in it. Remember, it was missing when kubectl set image command was used.
kubectl get deployments.apps my-deploy -o jsonpath='{.metadata.annotations.kubectl\.kubernetes\.io\/last-applied-configuration}' |jq .
{
"apiVersion": "apps/v1",
"kind": "Deployment",
"metadata": {
"annotations": {},
"creationTimestamp": null,
"labels": {
"app": "my-deploy"
},
"name": "my-deploy",
"namespace": "default"
},
"spec": {
"replicas": 1,
"selector": {
"matchLabels": {
"app": "my-deploy"
}
},
"strategy": {},
"template": {
"metadata": {
"creationTimestamp": null,
"labels": {
"app": "my-deploy"
}
},
"spec": {
"containers": [
{
"image": "flask",
"name": "nginx",
"resources": {}
}
]
}
}
},
"status": {}
}
Where is the "last-applied" annotation saved:
Just like everything else, Its saved in etcd , created the pod using the manifest provided in the question and ran raw etcd command to print the content. (in this dev environment, etcd was not encrypted).
ETCDCTL_API=3 etcdctl --cert /etc/kubernetes/pki/apiserver-etcd-client.crt --key /etc/kubernetes/pki/apiserver-etcd-client.key --cacert /etc/kubernetes/pki/etcd/ca.crt get /registry/pods/default/my-nginx
/registry/pods/default/my-nginx
k8s
v1Pod⚌
⚌
my-nginxdefault"*$a3s4b729-c96a-40f7-8de9-5d5f4ag21gfa2⚌⚌⚌b⚌
0kubectl.kubernetes.io/last-applied-configuration⚌{"apiVersion":"v1","kind":"Pod","metadata":{"annotations":{},"name":"my-nginx","namespace":"default"},"spec":{"containers":[{"image":"nginx:alpine","name":"my-nginx"}]}}
I see the following event from kubectl get events:
{
"apiVersion": "v1",
"count": 1,
"eventTime": null,
"firstTimestamp": "2019-12-04T19:52:51Z",
"involvedObject": {
"apiVersion": "v1",
"kind": "Pod",
"name": "example-deployment-55f789d54c-tlwnz",
"namespace": "default",
"resourceVersion": "82663",
"uid": "2fdbd034-16cf-11ea-bc4a-42010a800186"
},
"kind": "Event",
"lastTimestamp": "2019-12-04T19:52:51Z",
"message": "Unable to mount volumes for pod \"example-deployment-55f789d54c-tlwnz_default(2fdbd034-16cf-11ea-bc4a-42010a800186)\": timeout expired waiting for volumes to attach or mount for pod \"default\"/\"example-deployment-55f789d54c-tlwnz\". list of unmounted volumes=[nfs-volume]. list of unattached volumes=[nfs-volume default-token-kc7ks]",
"metadata": {
"creationTimestamp": "2019-12-04T19:52:51Z",
"name": "example-deployment-55f789d54c-tlwnz.15dd430deb31e8fd",
"namespace": "default",
"resourceVersion": "1529",
"selfLink": "/api/v1/namespaces/default/events/example-deployment-55f789d54c-tlwnz.15dd430deb31e8fd",
"uid": "a7c80266-16cf-11ea-bc4a-42010a800186"
},
"reason": "FailedMount",
"reportingComponent": "",
"reportingInstance": "",
"source": {
"component": "kubelet",
"host": "gke-test-a2e50ea5b9f1dd9-my-node-pool-5a20b1ac-vk9q"
},
"type": "Warning"
}
....
I've tried filtering by: kubectl get events --all-namespaces -o json --field-selector source.component=cluster-autoscaler but that errors with:
{
"apiVersion": "v1",
"items": [],
"kind": "List",
"metadata": {
"resourceVersion": "",
"selfLink": ""
}
}
Error from server (BadRequest): Unable to find "/v1, Resource=events" that match label selector "", field selector "source.component=cluster-autoscaler": field label not supported: source.component
How can I filter this?
Can be done using jq (though it does not return a JSON array - but individual JSON objects seperated by newlines):
kubectl get events --all-namespaces -o json | jq '.items[]|select(.source.component=="cluster-autoscaler")'
I am access my kubernetes dashboard using this url:
https://kubernetes.example.com/api/v1/namespaces/kube-system/services/kubernetes-dashboard/#/workload?namespace=default
what make me confusing is the return content just json string, not the login page. The json content is :
{
"kind": "Service",
"apiVersion": "v1",
"metadata": {
"name": "kubernetes-dashboard",
"namespace": "kube-system",
"selfLink": "/api/v1/namespaces/kube-system/services/kubernetes-dashboard",
"uid": "884240d7-8f3f-41a4-a3a0-a89649545c82",
"resourceVersion": "133822",
"creationTimestamp": "2019-09-21T16:21:19Z",
"labels": {
"addonmanager.kubernetes.io/mode": "Reconcile",
"k8s-app": "kubernetes-dashboard",
"kubernetes.io/cluster-service": "true"
},
"annotations": {
"kubectl.kubernetes.io/last-applied-configuration": "{\"apiVersion\":\"v1\",\"kind\":\"Service\",\"metadata\":{\"annotations\":{},\"labels\":{\"addonmanager.kubernetes.io/mode\":\"Reconcile\",\"k8s-app\":\"kubernetes-dashboard\",\"kubernetes.io/cluster-service\":\"true\"},\"name\":\"kubernetes-dashboard\",\"namespace\":\"kube-system\"},\"spec\":{\"ports\":[{\"port\":443,\"targetPort\":8443}],\"selector\":{\"k8s-app\":\"kubernetes-dashboard\"},\"type\":\"NodePort\"}}\n"
}
},
"spec": {
"ports": [
{
"protocol": "TCP",
"port": 443,
"targetPort": 8443,
"nodePort": 31085
}
],
"selector": {
"k8s-app": "kubernetes-dashboard"
},
"clusterIP": "10.254.75.193",
"type": "NodePort",
"sessionAffinity": "None",
"externalTrafficPolicy": "Cluster"
},
"status": {
"loadBalancer": {
}
}
}
this is my nginx forward config:
upstream kubernetes{
server 172.19.104.231:8001;
}
this is my kubernetes cluster proxy command:
kubectl proxy --address=0.0.0.0 --port=8001 --accept-hosts='^*$'
You are accessing the Kubernetes API to get the kubernetes-dashboard Service resource manifest. This is the JSON that you get back.
If you want to access the Service, you need to access the Service itself, not the Kubernetes API. You can do this for example with port forwarding:
kubectl port-forward svc/kubernetes-dashboard 8443:443
And then access the Service with:
curl localhost:8443/#/workload?namespace=default
Kubernetes documentation has clearer instructions now on how to deploy and access their dashboard:
https://kubernetes.io/docs/tasks/access-application-cluster/web-ui-dashboard/
I went to 127.0.0.1:8001 at first, and got the API JSON (as per the original question) before noticing the URL given under the kubectl proxy instruction:
http://localhost:8001/api/v1/namespaces/kubernetes-dashboard/services/https:kubernetes-dashboard:/proxy/.
I am running 1.6.2, and am hitting the /apis/batch/v2alpha1/namespaces/<namespace>/cronjobs endpoint, with a valid namespace and a request body of
{
"body": {
"apiVersion": "batch/v2alpha1",
"kind": "CronJob",
"metadata": {
"name": "hello"
},
"spec": {
"schedule": "*/1 * * * *",
"jobTemplate": {
"spec": {
"template": {
"spec": {
"containers": [
{
"name": "hello",
"image": "busybox",
"args": [
"/bin/sh",
"-c",
"date; echo Hello from the Kubernetes cluster"
]
}
],
"restartPolicy": "OnFailure"
}
}
}
}
}
}
}
I receive a response of
{
"kind": "Status",
"apiVersion": "v1",
"metadata": {},
"status": "Failure",
"message": "the server could not find the requested resource",
"reason": "NotFound",
"details": {},
"code": 404
}
According to the documentation, this endpoint should exist. I figure I probably have some setting set incorrectly, but I'm not sure which one and how to correct it. Any help is appreciated.
The v2alpha1 features are not enabled by default. Make sure you are starting your kube-apiserver with this switch to enable the CronJob resource: --runtime-config=batch/v2alpha1=true.
I have setup a Cluster with some deployments and services.
I can log into any of my pods and ping the pods from their pod network ips ( 172.x.x.x ) and they are successful.
But when I try to ping the services ClusterIP addresses from any of my pods they never respond, so I can't access my services.
Below is my Kibana deployment, and 10.254.77.135 is the IP I am trying to connect to from my other services, I also can't use this node port, it never responds
{
"kind": "Service",
"apiVersion": "v1",
"metadata": {
"name": "kibana",
"namespace": "default",
"selfLink": "/api/v1/namespaces/default/services/kibana",
"uid": "21498caf-569c-11e7-a801-0050568fc023",
"resourceVersion": "3282683",
"creationTimestamp": "2017-06-21T16:10:23Z",
"labels": {
"component": "elk",
"role": "kibana"
}
},
"spec": {
"ports": [
{
"name": "http",
"protocol": "TCP",
"port": 5601,
"targetPort": 5601,
"nodePort": 31671
}
],
"selector": {
"k8s-app": "kibana"
},
"clusterIP": "10.254.77.135",
"type": "NodePort",
"sessionAffinity": "None"
},
"status": {
"loadBalancer": {}
}
}
Not sure if this is your problem, but apparently ping doesn't work on services ClusterIP addresses because they are virtual addresses created by iptables rules that just redirect packets to the endpoints(pods).