Problem Facing: When I try to run kubectl apply command on both the files below and try to see the app in the browser in http://192.168.49.2:30080/ the app did not render.I tried to run minikube service fleetman - webapp --url but still no progress . Please Help !!!
Additional information :minikube ip -192.168.49.2 .
Note:I have installed docker Desktop app on my mac book air catalina.
Browser message: This site can’t be reached 192.168.49.2 took too long to respond.
Docker image Link :https://hub.docker.com/r/richardchesterwood/k8s-fleetman-webapp-angular
first-pod.yaml file
apiVersion: v1
kind: Pod
metadata:
name: webapp
labels :
mylabelname: webapp
spec:
containers:
- name: webapp
image: richardchesterwood/k8s-fleetman-webapp-angular:release0
webapp-services.yaml file
apiVersion: v1
kind: Service
metadata:
name: fleetman-webapp
spec:
# This defines which pods are going to be represented by this Service
# The service becomes a network endpoint for either other services
# or maybe external users to connect to (eg browser)
selector:
mylabelname: webapp
ports:
- name: http
port: 80
nodePort: 30080
type: NodePort
Try creating minikube with driver none:
$ minikube start --driver=none
The none driver allows advanced minikube users to skip VM creation, allowing minikube to be run on a user-supplied VM.
Hence you will be able to communicate to your app via your host (ie. user-supplied VM) network address.
Related
I'm using the kubernetes cluster built in to Docker Desktop to develop my application.
I would like to expose services inside the cluster as ports on localhost.
I can do so using kubectl expose deployment foobar --type=NodePort --port=30088, which creates a service like this:
apiVersion: v1
kind: Service
metadata:
labels:
role: web
name: foobar
spec:
externalTrafficPolicy: Cluster
ports:
- nodePort: 30088
port: 80
protocol: TCP
targetPort: 80
selector:
role: web
type: NodePort
But it only works for very high numbered ports. If I try something lower I get:
The Service "kafka-external" is invalid: spec.ports[0].nodePort: Invalid value: 9092: provided port is not in the valid range. The range of valid ports is 30000-32767
It seems there is a kubernetes apiserver setting called ServiceNodePortRange which would allow me to override this restriction, but I can't figure out how to set it on Docker's builtin cluster.
So my question is: how do I expose a specific, low-numbered port (like 9092) on Docker's kubernetes cluster? Is there a way to override that setting? Or a better way to expose the service than NodePort?
NodePort is intended to be a building block for load-balancers or other
ingress modes. This means it didn't matter which port you got as long as
you got one. This makes it a little clunky to use directly - you can't
have just any port. You can change the port range, but you run the risk of
conflicts with real things running on your nodes and with any pod HostPorts.
The default range is indeed 30000-32767 but it can be changed by setting the --service-node-port-range Update the file /etc/kubernetes/manifests/kube-apiserver.yaml and add the line --service-node-port-range=xxxxx-yyyyy.
In the Kubernetes cluster there is a kube-apiserver.yaml file which is in the directory - /etc/kubernetes/manifests/kube-apiserver.yaml but not on the kube-apiserver container/pod but on the master itself.
Login to Docker VM:
Add the following line to the pod spec:
spec:
containers:
- command:
- kube-apiserver
...
- --service-node-port-range=xxxxx-yyyyy # <-- add this line
...
Save and exit. Pod kube-apiserver will be restarted with new parameters.
Exit Docker VM (for screen: Ctrl-a,k , for container: Ctrl-d )
Check the results:
$ kubectl get pod kube-apiserver-docker-desktop -o yaml -n kube-system | less
Take a look: service-pod-range, changing pod range, changing-nodeport-range.
I am running a cluster in default namespace with all the pods in Running state.
I have an issue, I am trying to telnet from one pod to another pod using the pod hostname 'abcd-7988b76669-lgp8l' but I am not able to connect. although it works if I use pods internal ip. Why does the dns is not resolved?
I looked at
kubectl get po -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-6955765f44-5lpfd 1/1 Running 0 12h
coredns-6955765f44-9cvnb 1/1 Running 0 12h
Anybody has any idea how to connect from one pod to another using hostname resolution ?
First of all it is worth mentioning that typically you won't connect to individual Pods using their domain names. One good reason for that is their ephemeral nature. Note that typically you don't create plain Pods but controller such as Deployment which manages your Pods and ensures that specific number of Pods of a certain kind is constantly up and running. Pods may be often deleted and recreated hence you should never rely on their domain names in your applications. Typically you will expose them to another apps e.g. running in other Pods via Service.
Although using invididual Pod's domain name is not recommended, it is still possible. You can do it just for fun or learning/experimenting purposes.
As #David already mentioned you would help us much more in providing you a comprehensive answer if you EDIT your question and provide a few important details, showing what you've tried already such as your Pods and Services definitions in yaml format.
Answering literally to your question posted in the title:
minikube how to connect from one pod to another using hostnames?
You won't be able to connect to a Pod using simply its hostname. You can e.g. ping your backend Pods exposed via ClusterIP Service by simply pinging the <service-name> (provided it is in the same namespace as the Pod your pinging from).
Keep in mind however that it doesn't work for Pods - neither Pods names nor their hostnames are resolvable by cluster DNS.
You should be able to connect to an individual Pod using its fully quallified domain name (FQDN) provided you have configured everything properly. Just make sure you didn't overlook any of the steps described here:
Make sure you've created a simple Headless Service which may look like this:
apiVersion: v1
kind: Service
metadata:
name: default-subdomain
spec:
selector:
name: busybox
clusterIP: None
Make sure that your Pods definitions didn't lack any important details:
apiVersion: v1
kind: Pod
metadata:
name: busybox1
labels:
name: busybox
spec:
hostname: busybox-1
subdomain: default-subdomain
containers:
- image: busybox:1.28
command:
- sleep
- "3600"
name: busybox
---
apiVersion: v1
kind: Pod
metadata:
name: busybox2
labels:
name: busybox
spec:
hostname: busybox-2
subdomain: default-subdomain
containers:
- image: busybox:1.28
command:
- sleep
- "3600"
name: busybox
Speaking about important details, pay special attention that you correctly defined hostname and subdomain in Pod specification and that labels used by Pods match the labels used by Service's selector.
Once everything is configured properly you will be able to attach to Pod busybox1 and ping Pod busybox2 by using its FQDN like in the example below:
$ kubectl exec -ti busybox1 -- /bin/sh
/ # ping busybox-2.default-subdomain.default.svc.cluster.local
PING busybox-2.default-subdomain.default.svc.cluster.local (10.16.0.109): 56 data bytes
64 bytes from 10.16.0.109: seq=0 ttl=64 time=0.051 ms
64 bytes from 10.16.0.109: seq=1 ttl=64 time=0.082 ms
64 bytes from 10.16.0.109: seq=2 ttl=64 time=0.081 ms
I hope this helps.
Fist time deploying to OpenShift (actually minishift in my Windows 10 Pro). Any sample application I deploied successfully resulted in:
From Web Console I see a weird message "Build #1 is pending" although I saw it was successfully from PowerShell
I found someone fixing similiar issue changing to 0.0.0.0 (enter link description here) but I give a try and it isn't the solution in my case.
Here are the full logs and how I am deploying
PS C:\to_learn\docker-compose-to-minishift\first-try> oc new-app https://github.com/openshift/nodejs-ex warning: Cannot check if git requires authentication.
--> Found image 93de123 (16 months old) in image stream "openshift/nodejs" under tag "10" for "nodejs"
Node.js 10.12.0
---------------
Node.js available as docker container is a base platform for building and running various Node.js applications and frameworks. Node.js is a platform built on Chrome's JavaScript runtime for easily building fast, scalable network applications. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices.
Tags: builder, nodejs, nodejs-10.12.0
* The source repository appears to match: nodejs
* A source build using source code from https://github.com/openshift/nodejs-ex will be created
* The resulting image will be pushed to image stream tag "nodejs-ex:latest"
* Use 'start-build' to trigger a new build
* WARNING: this source repository may require credentials.
Create a secret with your git credentials and use 'set build-secret' to assign it to the build config.
* This image will be deployed in deployment config "nodejs-ex"
* Port 8080/tcp will be load balanced by service "nodejs-ex"
* Other containers can access this service through the hostname "nodejs-ex"
--> Creating resources ...
imagestream.image.openshift.io "nodejs-ex" created
buildconfig.build.openshift.io "nodejs-ex" created
deploymentconfig.apps.openshift.io "nodejs-ex" created
service "nodejs-ex" created
--> Success
Build scheduled, use 'oc logs -f bc/nodejs-ex' to track its progress.
Application is not exposed. You can expose services to the outside world by executing one or more of the commands below:
'oc expose svc/nodejs-ex'
Run 'oc status' to view your app.
PS C:\to_learn\docker-compose-to-minishift\first-try> oc get bc/nodejs-ex -o yaml apiVersion: build.openshift.io/v1
kind: BuildConfig
metadata:
annotations:
openshift.io/generated-by: OpenShiftNewApp
creationTimestamp: 2020-02-20T20:10:38Z
labels:
app: nodejs-ex
name: nodejs-ex
namespace: samplepipeline
resourceVersion: "1123211"
selfLink: /apis/build.openshift.io/v1/namespaces/samplepipeline/buildconfigs/nodejs-ex
uid: 1003675e-541d-11ea-9577-080027aefe4e
spec:
failedBuildsHistoryLimit: 5
nodeSelector: null
output:
to:
kind: ImageStreamTag
name: nodejs-ex:latest
postCommit: {}
resources: {}
runPolicy: Serial
source:
git:
uri: https://github.com/openshift/nodejs-ex
type: Git
strategy:
sourceStrategy:
from:
kind: ImageStreamTag
name: nodejs:10
namespace: openshift
type: Source
successfulBuildsHistoryLimit: 5
triggers:
- github:
secret: c3FoC0RRfTy_76WEOTNg
type: GitHub
- generic:
secret: vlKqJQ3ZBxfP4HWce_Oz
type: Generic
- type: ConfigChange
- imageChange:
lastTriggeredImageID: 172.30.1.1:5000/openshift/nodejs#sha256:3cc041334eef8d5853078a0190e46a2998a70ad98320db512968f1de0561705e
type: ImageChange
status:
lastVersion: 1
I am displaying the output of the "docker ps -a command" to list all the containers to my Html page. I want to change the port of these containers using a button in the page itself. In docker normally if the container is running, I would run a docker stop on the container-id and restart it by adding the -p HOSTPORT:CONTAINERPORT to the command. But since all the containers running are Kubernetes containers/pods, stopping them will re-create a new pod/container with a different name. So how do I change the port of the container/pod in such cases?
output of "docker ps -a command"
NAMES CONTAINER ID STATUS
k8s_nginx_nginx-6cdb6c86d4-z7m7m 56711e6de1be Up 2 seconds
k8s_POD_nginx-6cdb6c86d4-z7m7m_d 70b21761cb74 Up 3 seconds
k8s_coredns_coredns-5c98db65d4-7 dfb21bb7c7f4 Up 7 days
k8s_POD_coredns-5c98db65d4-7djs8 a336be8230ce Up 7 days
k8s_POD_kube-proxy-9722h_kube-sy 5e290420dec4 Up 7 days
k8s_POD_kube-apiserver-wootz_kub a23dea72b38b Exited (255) 7 days ago
nginx.yaml
apiVersion: v1
kind: Service
metadata:
name: nginx
labels:
app: nginx
spec:
type: NodePort
ports:
- name: nginxport
port: 80
targetPort: 80
nodePort: 30000
selector:
app: nginx
tier: frontend
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx
labels:
app: nginx
spec:
selector:
matchLabels:
app: nginx
tier: frontend
template:
metadata:
labels:
app: nginx
tier: frontend
spec:
containers:
- image: suji165475/devops-sample:mxgraph
name: nginx
ports:
- containerPort: 80
name: nginxport
So how can I change the port of any of the containers/pod ?
Most of the attributes of a PodSpec cannot be changed once the pod has been created. The port information is inside the containers array, and the linked documentation explicitly notes that containers "Cannot be updated." You must delete and recreate the pod if you want to change the ports it makes visible (or most of its other properties); there is no other way to do it.
You almost never directly deal with Pods (and for that matter you almost never mix plain Docker containers and Kubernetes on the same host). Typically you create a Deployment object, which can be updated in place, and it takes responsibility for creating and deleting Pods for you.
(The corollary to this is that if you're trying to manually delete and recreate Pods, in isolation, changing their properties, but these Pods are also managed by Deployments or StatefulSets or DaemonSets, the controller will notice that a replica is missing when you delete it and recreate it, with its original settings.)
Answering OP's question, as per his comments.
I want to change the port on which my kubernetes containers run. I want to change the nodeport,container port,targetport for it. so how can do this using kubectl patch command for both the service and deployment?
kubectl patch deployment nginx --type json -p='[{"op": "replace", "path": "/spec/template/spec/containers/0/ports/0/containerPort", "new port"}]' && \
kubectl patch service nginx --type json -p='[{"op": "replace", "path": "/spec/type/spec/ports/0/targetPort", "new port"}]' && \
kubectl patch service nginx --type json -p='[{"op": "replace", "path": "/spec/type/spec/ports/0/nodePort", "new port"}]'
Here is how to change pod specs,
kubectl patch pod valid-pod --type='json' -p='[{"op": "replace", "path": "/spec/containers/0/ports/0/port", "value":"new port"}]'
As David said, Pods aren't really used directly without a deployment.
What you would normally do, have a deployment with deploys the pods and that configuration can be then edited using kubectl.
Try using something like this,
kubectl patch deployment valid-deployment --type json -p='[{"op": "replace", "path": "/spec/template/spec/containers/0/ports/0/port", "new port"}]'
If you patch the deployment, the pods automatically restart.
That being said, if you change the port of the container, the service targetport would have to be changed too. The simple fix for that would to make sure all your container ports have name attribute filled which are mapped to their appropriate k8s services.
I'm working for a spinnaker for create a new CD pipeline.
I've deployed halyard in a docker container on my computer, and also deployed spinnaker from it to the Google Kubernetes Engine.
After all of them, I've prepared a new ingress yaml file, shown as below.
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: jenkins-cloud
namespace: spinnaker
spec:
rules:
- http:
paths:
- path: /*
backend:
serviceName: spin-deck
servicePort: 9000
After accessing the spinnaker UI via a public IP, I got an error, shown as below.
Error fetching applications. Check that your gate endpoint is accessible.
After all of them, I've checked the docs about it and I've run some commands shown as below.
I've checked the service data on my K8S cluster.
spin-deck NodePort 10.11.245.236 <none> 9000:32111/TCP 1h
spin-gate NodePort 10.11.251.78 <none> 8084:31686/TCP 1h
For UI
hal config security ui edit --override-base-url "http://spin-deck.spinnaker:9000"
For API
hal config security api edit --override-base-url "http://spin-gate.spinnaker:8084"
After running these commands and redeploying spinnaker, the error repeated itself.
How can I solve the problem of accessing the spinnaker gate from the UI?
--override-base-url should be populated without port.