Kubernetes connection error in Mac - macos

OS : OSX (mac)
Docker : 18.06.0-ce (edge)
Kubernetes : 1.10.3
I use Kubernetes for the first time.
I tried Google but could not find the manual for Kubernetes, which operates on the Mac.
Running kubectl version outputs The connection to the
server localhost:8080 was refused - did you specify the right host or port?

I came across this issue when changing from minikube to the Docker Desktop supplied Kubernetes. For me, the issue was caused by a stale .kube configuration. Posting my workaround here as this was the first result I found on google when looking to troubleshoot the issue.
1. Uninstall Minikube
I had originally installed with homebrew: brew uninstall minikube. If installed using other methods, go back to your install source for uninstall info.
After minikube was uninstalled, I restarted my machine which may or may not have been necessary but it is what I did.
2. Disable Kubernetes in docker Desktop
Open Docker Desktop preferences, click Kubernetes menu
De-select 'Enable Kubernetes' checkbox. Click Apply & Restart
3. Remove old kube and minikube config
Open terminal to your home directory.
Check for settings directories: ls -al and look for .kube and .minikube.
Remove .kube settings: rm -rf ./.kube.
Remove .minikube settings: rm -rf ./.minikube.
Confirm: ls -al and make sure the .kube and .minikube directories have been deleted.
If everything looks good, close terminal.
4. Re-enable Kubernetes in Docker Desktop
Open Docker Desktop preferences, click Kubernetes menu
Select 'Enable Kubernetes' checkbox. Click Apply & Restart
Open new terminal window and run kubectl version. You should see info for Client Version and Server Version if everything worked.

When you run kubectl, the .kube/config file is read in your home directory, thus telling which cluster you want to connect to using --context=<cluster-name>
What your error output is telling you is that it is unable to find a listening kubernetes API endpoint upon which to run those commands. It is looking for a cluster at localhost:8080
This endpoint will vary depending on how and where you installed Kubernetes. How are you running Kubernetes?
Are you using the bundled Docker/Kubernetes for Mac as mentioned here? - Docker for Mac Kubernetes or are you using a tool like MiniKube? - MiniKube

You might notice this error The connection to the server localhost:8080 was refused - did you specify the right host or port? because of your local minikube server might be down.
You have to start the existing minikube instance using - minikube start (I'm assuming your local minikube configured with docker driver earlier like: minikube start --driver=docker)
If not working above step then you have to delete the existing minikube then start it again:
minikube delete
minikube start --driver=docker

I had faced the same issue and my user id did not had the admin privileges, once the chown is done, Kubernetes started working.Hope this helps

Related

Cannot access Flink dashboard localhost:8081 on windows

I follow the first steps to install Flink.
I can start the cluster without any problem
$ start-cluster.sh
Starting cluster.
Starting standalonesession daemon on host DESKTOP-....
Starting taskexecutor daemon on host DESKTOP-....
But I don't get any status from
$ ps aux | grep flink
I can also not access the dashboard via localhost:8081.
There is an older post having these issues, but the solution didn't work for me, since the described conf files do no longer exist, apparently.
My JAVA_HOME is set as C:\Progra~1\Java\jdk1.8.0_311 to avoid issues with the space in Program Files.
Can you check the logs in the /logs folder? I'm suspecting that C:\Program Files\ could still cause issues because of the space there.
go to download Flink folder and try bash command
$./bin/start-cluster.sh --daemon bootstrap-server localhost:8081
and run code one more
$ ./bin/flink run examples/streaming/WordCount.jar
if you finished run above code which not issue, go to localhost:8081
This still seems to be problematic. I tried to run from Windows Subsystem for Linux (WSL).
I have the following versions: java 11.0.16 and flink 1.15.2.
sudo apt-get update
sudo apt install openjdk-11-jre-headless
export FLINK_HOME=/mnt/c/Projects/Apache/flink-1.15.2
I set the following in flink-conf.yaml
rest.port: 8081
rest.address: localhost
rest.bind-adress: 0.0.0.0
Whereby I changed the bind address for localhost to 0.0.0.0 this seems to have fixed the problem.
$FLINK_HOME/bin/start-cluster.sh
Now I can access the Flink Web Dashboard.

Kubernetes fails to start on Docker Desktop without direct internet access

I'm running Docker Desktop 3.6.0 on Windows 10 with WSL2.
When I try to enable Kubernetes I only see "Failed to start" within the Docker Desktop UI.
Docker itself works fine. Not sure how I can get any further logs.
Here the output from kubectl version:
kubectl version
Client Version: version.Info{Major:"1", Minor:"21", GitVersion:"v1.21.3", GitCommit:"ca643a4d1f7bfe34773c74f79527be4afd95bf39", GitTreeState:"clean", BuildDate:"2021-07-15T21:04:39Z", GoVersion:"go1.16.6", Compiler:"gc", Platform:"windows/amd64"}
Error from server (InternalError): an error on the server ("") has prevented the request from succeeding
From other posts it seems that and internet connections is required for initial setup:
https://stackoverflow.com/a/52765732/1100559
https://stackoverflow.com/a/63318739/1100559
Direct internet connection is not possible on my work environment, I can only manually copy required images on my pc.
I also do not have admin access.
Is there a way to manually setup Kubernetes on Docker Desktop or somehow indicate where the required images can be found?
I have a nexus Docker repository where I can push required images to.
I have changed the ~\.docker\daemon.json and added my docker repository in insecure-registries. After first login docker is able to pull images from there and run them.
Already tried to reset or enable and disable Kubernetes. Also deleting ~/.kube/config did not work.
High level answer...
Get a docker registry
If you work for an old skool cool enterprise; use JFrog Artifactory
If you just want to get it to work; use Harbor
GitHub and GitLab (depending on license) have registries available too...
Edit the docker daemon on the kubernetes nodes (your workstation) to only pull from these registries.
if redhat; /etc/containers/registries.conf
if debain; /etc/docker/daemon.json
you might be able to hack a /etc/hosts entry too...
Populate the new registry
Run kubernetes and yoiu should be good to go. Depending on the configuration you choose you may need to add a registry credential secret.

failing to start docker engine open //./pipe/docker_engine

I'm receiving the following error in docker on windows 10 laptop.
I've try to reinstall and restart but nothing helps.
The docker service is running OK but what i understand that i have a problem with the docker daemon (from what i read)
The whole issue started when i run the 2 commands:
net stop com.docker.service
net start com.docker.service
from there on i keep getting the error below and cannot solve it.
C:\Users\xxxx>docker images error during connect: Get
http://%2F%2F.%2Fpipe%2Fdocker_engine/v1.30/images/json: open
//./pipe/docker_engine: The system cannot find the file specified. In
the default daemon configuration on Windows, the docker client must be
run elevated to connect. This error may also indicate that the docker
daemon is not running.
anyone succeed to solve it?
docker client must be run elevated to connect
This indicates that you do not have enough permissions. Try starting the terminal as administrator.
I run Docker remotely as a non admin user.
For this the user running docker should have full permission to location where Docker is installed.
User should be part of docker_users group
docker daemon runs on port 2375 by default. Try to whitelist this port. Allow incoming connections to 2375 in Windows Firewall settings
Restart your docker daemon and Docker service.
Restart the running Docker instance[Docker for Windows] if required. You do not have to reinstall.

How to enable Docker API access from Windows running Docker Toolbox (docker machine)

I am running the latest Docker Toolbox, using latest Oracle VirtualBox, with Windows 7 as a host OS.
I am trying to enable non-TLS access to Docker remote API, so I could use Postman REST client running on Windows and hit docker API running on docker-machine in the VirtualBox. I found that if Docker configuration included -H tcp://0.0.0.0:2375, that would do the trick exposing the API on port 2375 of the docker machine, but for the life of me I can't find where this configuration is stored and can be changed.
I did docker-machine ssh from the Toolbox CLI, and then went and pocked around the /etc/init.d/docker file, but no changes to the file survive docker-machine restart.
I was able to find answer to this question for Ubuntu and OSX, but not for Windows.
#CarlosRafaelRamirez mentioned the right place, but I will add a few details and provide more detailed, step-by-step instructions, because Windows devs are often not fluent in Linux ecosystem.
Disclaimer: following steps make it possible to hit Docker Remote API from Windows host, but please keep in mind two things:
This should not be done in production as it makes Docker machine very not secure.
Current solution disables most of the docker-machine and all docker CLI functionality. docker-machine ssh remains operational, forcing one to SSH into docker machine to access docker commands.
Solution
Now, here are the steps necessary to switch Docker API to non-TLS port. (Docker machine name is assumed to be "default". If your machine name has a different name, you will need to specify it in the commands below.)
Start "Docker Quickstart Terminal". It starts Bash shell and is the place where all following commands will be run. Run docker-machine ip command and note the IP address of the docker host machine. Then do
docker-machine ssh
cd /var/lib/boot2docker
sudo vi profile This starts "vi" editor in elevated privileges mode required for editing "profile" file, where Docker host settings are. (If as a Windows user you are not familiar with vi, here's is super-basic crash course on it. When file is open in the vi, vi is not in editing mode. Press "i" to start edit mode. Now you can make changes. After you made all the changes, hit Esc and then ZZ to save changes and exit vi. If you need to exit vi without saving changes, after Esc please type :q! and hit Enter. ":" turns on vi's command mode, and "q!" command means exit without saving. Detailed vi command info is here.)
Using vi, change DOCKER_HOST to be DOCKER_HOST='-H tcp://0.0.0.0:2375', and set DOCKER_TLS=no. Save changes as described above.
exit to leave SSH session.
docker-machine restart
After doocker machine has restarted, your sould be able to hit docker API URL, like http://dokerMachineIp:2375/containers/json?all=1, and get valid JSON back.
This is the end of steps required to achieve the main goal.
However, if at this point you try to run docker-machine config or docker images, you will see an error message indicating that docker CLI client is trying to get to the Docker through the old port/TLS settings, which is understandable. What was not expected to me though, is that even after I followed all the Getting Started directions, and ran export DOCKER_HOST=tcp://192.168.99.101:2375 and export DOCKER_TLS_VERIFY=0, resulting in
$ env | grep DOCKER
DOCKER_HOST=tcp://192.168.99.101:2375
DOCKER_MACHINE_NAME=default
DOCKER_TLS_VERIFY=0
DOCKER_TOOLBOX_INSTALL_PATH=C:\Program Files\Docker Toolbox
DOCKER_CERT_PATH=C:\Users\USERNAME\.docker\machine\machines\default
the result was the same:
$ docker-machine env
Error checking TLS connection: Error checking and/or regenerating the certs: There was an error validating certificates for host
"192.168.99.101:2376"
If you see a problem with how I changed environment variables to point Docker CLI to the new Docker host address, please comment.
To work around this problem, use docker-machine ssh command and run your docker commands after that.
I encountered the same problem and thanks to #VladH made it working not changing any internal Docker profile properties. All you have to do is correctly define Windows local env variables (or configure maven plugin properties, if you use io.fabric8 docker-maven-plugin).
Note that 2375 port is used for non-TLS connections, and 2376 only for TLS connections.
DOCKER_HOST=tcp://192.168.99.100:2376
DOCKER_TLS_VERIFY=0
DOCKER_TOOLBOX_INSTALL_PATH=C:\Program Files\Docker Toolbox
DOCKER_CERT_PATH=C:\Users\USERNAME\.docker\machine\machines\default

Is it possible to run kubernetes as a docker container?

I'm very new to kubernetes and trying to conceptualize it as well as set it up locally in order to try developing something on it.
There's a confound though that I am running on a windows machine.
Their "getting started" documentation in github says you have to run Linux to use kubernetes.
As docker runs on windows, I was wondering if it was possible to create a kubernetes instance as a container in windows docker and use it to manage the rest of the cluster in the same windows docker instance.
From reading the setup instructions, it seems like docker, kubernetes, and something called etcd all have to run "in parallel" on a single host operating system... But part of me thinks it might be possible to
Start docker, boot 'default' machine.
Create kubernetes container - configure to communicate with the existing docker 'default' machine
Use kubernetes to manage existing docker.
Pipe dream? Wrongheaded foolishness? I see there are some options around running it in a vagrant instance. Does that mean docker, etcd, & kubernetes together in a single VM (which in turn creates a cluster of virtual machines inside it?)
I feel like I need to draw a picture of what this all looks like in terms of physical hardware and "memory boxes" to really wrap my head around this.
With Windows, you need docker-machine and boot2docker VMs to run anything docker related.
There is no (not yet) "docker for Windows".
Note that issue 7428 mentioned "Can't run kubernetes within boot2docker".
So even when you follow instructions (from a default VM created with docker-machine), you might still get errors:
➜ workspace docker run --net=host -d -v /var/run/docker.sock:/var/run/docker.sock gcr.io/google_containers/hyperkube:v0.14.2 /hyperkube kubelet --api_servers=http://localhost:8080 --v=2 --address=0.0.0.0 --enable_server --hostname_override=127.0.0.1 --config=/etc/kubernetes/manifests
ee0b490f74f6bc9b70c1336115487b38d124bdcebf09b248cec91832e0e9af1d
➜ workspace docker logs -f ee0b490f74f6bc9b70c1336115487b38d124bdcebf09b248cec91832e0e9af1d
W0428 09:09:41.479862 1 server.go:249] Could not load kubernetes auth path: stat : no such file or directory. Continuing with defaults.
I0428 09:09:41.479989 1 server.go:168] Using root directory: /var/lib/kubelet
The alternative would be to try on a full-fledge Linux VM (like the latest Ubuntu), instead of a boot2docker-like VM (based on a TinyCore distro).
All k8s components can be raised up with hyperkube, which helps you bring up a containerized one.
If you're able to run docker on windows, it would probably work. I haven't tried it on windows personally.

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