I'm trying to start minikube on ubuntu 18.04 inside nginx proxy manager docker network in order to setup some kubernetes services and manage the domain names and the proxy hosts in the nginx proxy manager platform.
so I have nginxproxymanager_default docker network and when I run minikube start --network=nginxproxymanager_default I get
Exiting due to GUEST_PROVISION: Failed to start host: can't create with that IP, address already in use
what might I been doing wrong?
A similar error was reported with kubernetes/minikube issue 12894
please check whether there are other services using that IP address, and try starting minikube again.
Considering minikube start man page
--network string
network to run minikube with.
Now it is used by docker/podman and KVM drivers.
If left empty, minikube will create a new network.
Using an existing NGiNX network (as opposed to docker/podman) might not be supported.
I have seen NGiNX set up as ingress, not directly as "network".
Related
I have a NAS where I am running various web apps in docker containers through docker-compose. I want some of these web apps to be accessible through the internet, not only when I am connected to my home network.
The problem I'm currently facing is that while cloudflare is able to expose the default web apps (default NAS management 192.168.1.135:80 can be mapped to subdomain.domain.com, for instance), it is unable to expose any docker container I try to run (192.168.1.135:4444 cannot be mapped to subdomain2.domain.com), and I receive a 502 bad gateway error with every app I have tried so far.
The configuration shouldn't be the issue, and it's definitely not the NoTLSVerify flag because the apps run on HTTP and I have configured it that way, so I am out of options to know what is going on and how to solve it.
Looks like the apps you're running on your NAS are proxied through the docker runtime. Consequently, the IP:port you need to add to the cloudflare tunnel config is the one that is reachable from the Host (not the IP of the host itself).
If the host is 192.168.1.135, you need to know which the the IP (internal to the docker network) of the app that you want to access from the outside, typically in the 172.0.0.1/24 range.
Example: If the containers running the apps you want to access are running on 172.0.0.2:4444 for app1 and 172.0.0.3:5555 for app2, the cloudflare config would look like this:
tunnel: the_ID_of_the_tunnel
credentials-file: /root/.cloudflared/the_ID_of_the_tunnel.json
ingress:
- hostname: yourapp1.example.com
service: http://172.0.0.2:4444
- hostname: ypurapp2.example.com
service: http://172.0.0.3:5555
- service: http_status:404
See more details and a video here: How to redirect subdomain to port (docker)
Turns out the problem is due to how docker works with networks, not with how Cloudflare accesses them. I first had to create a network that connected both containers, since adding cloudflare to my docker-compose file didn't work for some reason.
Create a docker network docker network create tunnel
Run docker without specifying the network docker run -d --name cloudflare cloudflare/cloudflared:latest tunnel --no-autoupdate run --token
Add the docker to the network docker network connect tunnel cloudflare
Run the container (note the container should have, as you specified, the network name identical to the one you created earlier, but cloudflare should not be in your docker-compose file) docker-compose up
In the cloudflare tunnel config, you will have to specify the docker internal address of your container (as #lu4t suggested). You can identify the address with docker inspect -f '{{range.NetworkSettings.Networks}}{{.IPAddress}}{{end}}' container
I have a running k3d Kubernetes cluster:
$ kubectl cluster-info
Kubernetes master is running at https://0.0.0.0:6550
CoreDNS is running at https://0.0.0.0:6550/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy
Metrics-server is running at https://0.0.0.0:6550/api/v1/namespaces/kube-system/services/https:metrics-server:/proxy
I have a python script that uses the kubernetes client api and manages namespaces, deployments, pod, etc. This works just fine in my local environment because I have all the necessary python modules installed and have direct access to my local k8s cluster. My goal is to containerize so that this same script is successfully run for my colleagues on their systems.
While running the same python script in a docker container, I receive connection errors:
urllib3.exceptions.MaxRetryError: HTTPSConnectionPool(host='172.17.0.1', port=6550): Max retries exceeded with url: /api/v1/namespaces (Caused by NewConnectionError('<urllib3.connection.HTTPSConnection object at 0x7f8b637c5d68>: Failed to establish a new connection: [Errno 113] No route to host',))
172.17.0.1 is my docker0 bridge address so assumed that would resolve or forward traffic to my localhost. I have tried loading k8s configuration from my local .kube/config which references server: https://0.0.0.0:6550 and also creating a separate config file with server: https://172.17.0.1:6550 and both give the same No route to host error (with the respective ip address in the HTTPSConnectionPool(host=...))
One idea I was pursing was running a socat process outside the container and tunnel traffic from inside the container across a bridge socket mounted in from the outside, but looks like the docker image I need to use does not have socat installed. However, I get the feeling like the real solution should be much simplier than all of this.
Certainly there have been other instances of a docker container needing access to a k8s cluster served outside of the docker network. How is this connection typically established?
Use docker network command to create a predefined network
You can pass --network to attach k3d to an existing Docker network and also to docker run to do the same for another container
https://k3d.io/internals/networking/
From a Spring Boot application running on a docker container, I am trying to connect to Rabbit MQ, Storm and other services which are also running on a docker container. It is working fine when using IP address like x.x.x.x but the same is not working when using the DNS name for that IP. In the command prompt I am able to ping and get a successful response for the same DNS name. Requesting for your help and support in this issue.
You said that you can resolve DNS on the command line. If you mean the command line of the host machine (outside of of the docker container), then the issue is probably with the container's own DNS settings.
A container has it's own network settings. Take a look at the /etc/resolv.conf file being used by the Spring Boot container - this will show you that container's DNS settings.
I am currently developing docker containers using visual studio, and these container images are supposed to run in a kubernetes cluster that I am also running locally.
Currently, the docker container that is running via visual studio is not being deployed to a kubernetes cluster, but for some reason am I able to ping the kubernetes pod's ip address from the docker container, but for which I don't quite understand; should they not be separated, and not be able to reach each other?
And it cannot be located on the kubernetes dashboard?
And since they are connected, why can't I use the kubernetes service to connect to my pod from my docker container?
The docker container is capable of pinging the cluster IP, meaning that it is reachable.
nslookup the service is not able to resolve the hostname.
So, as I already stated in the comment:
When Docker is installed, a default bridge network named docker0 is
created. Each new Docker container is automatically attached to this
network, unless a custom network is specified.
Thats mean you are able to ping containers by their respective IP. But you are not able to resolve DNS names of cluster objects - you VM know nothing about internal cluster DNS server.
Few option what you can do:
1) explicitly add record of cluster DNS to /etc/hosts inside VM
2) add a record to /etc/resolv.conf with nameserver and search inside VM. See one of my answers related to DNS resolution on stack: nslookup does not resolve Kubernetes.default
3)use dnsmasq as described in Configuring your Linux host to resolve a local Kubernetes cluster’s service URLs article. Btw I highly recommend you read it from the beginning till the end. It greatly describes how to work with DNS and what workaround you can use.
Hope it helps.
An application server is running as one Docker container and database running in another container. IP address of the database server is obtained as:
sudo docker inspect -f '{{ .NetworkSettings.IPAddress }}' db
Setting up JDBC resource in the application server to point to the database gives "java.net.ConnectException".
Linking containers is not an option since that only works on the same host.
How do I ensure that IP address of the database container is visible to the application server container?
If you want private networking between docker containers on remote hosts you can use weave to setup an overlay network between docker containers. If you don't need a private network just expose the ports using the -p switch and configure the addresses of the host machine as the destination IP in the required docker container.
One simple way to solve this would be using Weave. It allows you to create many application-specific networks that can span multiple hosts as well as datacenters. It also has a very neat DNS-based service discovery mechanism.
I should disclaim, I am one of Weave engineering team.
Linking containers is not an option since that only works on the same host.
So are you saying your application is a container running on docker server 1 and your db is a container on docker server 2? If so, you treat it like ordinary remote hosts. Your DB port needs to be exposed on docker server 2 and that IP:port needs to be configured into your application server, typically via environment variables.
The per host docker subnetwork is a Private Network. It's perhaps possible to have this address be routable, but it would be much pain. And it's further complicated because container IP's are not static.
What you need to do is publish the ports/services up to the host (via PORT in dockerfile and -p in your docker run) Then you just do host->host. You can resolve hosts by IP, Environment Variables, or good old DNS.
Few things were missing that were not allowing the cross-container communication:
WildFly was not bound to 0.0.0.0 and thus was only accepting requests on eht0. This was fixed using "-b 0.0.0.0".
Firewall was not allowing the containers to communication. This was removed using "systemctl stop firewall; systemctl disable firewall"
Virtual Box image required a Host-only adapter
After this, the containers are able to communicate. Complete details are available at:
http://blog.arungupta.me/2014/12/wildfly-javaee7-mysql-link-two-docker-container-techtip65/