Questions tagged [networking]

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8 answers
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How to get kubernetes pod network CIDR

I have a running k8s cluster initialized with kubeadm. On initialization, I did not pass the option --pod-network-cidr How do I get the CIDR of the pod network I tried Looking at the /etc/...
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11 votes
1 answer
16k views

Internal network between container Docker Compose with outgoing connection

I am a newbie to Docker. I am trying to run my application containing from multiple containers Here is my docker-compose.yml file version: '3.3' services: php-service: container_name: 'php-...
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6 votes
2 answers
6k views

Why should you do port mapping for docker containers?

I have been using docker for a few months and I am just a developer not a DevOps or a networking person. However, I came across a docker-compose which maps an external port to an internal port. ...
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  • 163
6 votes
1 answer
1k views

Networking between Docker containers

I have a docker container 'A' on a host 10.11.12.13 listening on port 0.0.0.0:8443->8443/tcp I have another container 'B' on same host how wants to talk to 'A' on 8443 via host. Thus when I run ...
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6 votes
2 answers
144 views

Securing communication between cloud VMs without private networks. Any strategy besides building own VPN? Spiped?

I am working on an application that requires a number of different services (web application + database + worker queues, XMPP server for messaging, redis, central authentication via LDAP, etc). For my ...
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  • 161
5 votes
1 answer
459 views

How to prevent Azure Traffic Manager from routing over high latency connections in a fail-over scenario?

We have a service hosted in four regions, two in North America and two in Europe. We are using Azure Traffic Manager to provide: Performance-based routing - that is routing consumers to the service ...
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4 votes
1 answer
182 views

K8s cluster in peered VPC can't reach RDS cluster

I have two K8s clusters in the same VPC that I want to connect to an MySQL Aurora RDS cluster. One of the clusters can reach the RDS cluster just fine. The other, however, cannot. I'll call these eks-...
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4 votes
1 answer
2k views

Bridged network adapter for Packer + VirtualBox?

So, I load an .ova image with packer of a minimal ubuntu linux installation. I realized after everything went through (Provisioners etc) and it successfully exported the output file. However, when ...
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  • 105
4 votes
1 answer
4k views

How to fix a "heartbeat failure" in Docker Swarm?

My cluster is currently located in a single data center. I've been trying to change that by adding a single worker node from another data center, but so far it hasn't worked. I'm able to make this ...
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  • 183
3 votes
3 answers
375 views

SSH tunneling on steroids

I have a remote redis machine with no ssh and no open ports except to the same lan + a remote machine (on the same lan) with ssh + my pc outside the lan. What I'm trying to do (mostly to see if it's ...
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3 votes
2 answers
7k views

VPN container providing access to host's LAN?

I'm kinda new to this Docker thing and I'm interested in getting a biffed up VPS for some containers (websites/data, mysql, nginx, rocket.chat, etc) but I wouldn't like to access them in the wild (...
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  • 133
3 votes
1 answer
198 views

Point docker container DNS to specific port?

I was wondering if it was possible to assign the DNS server a docker container is querying (via docker run --dns, or otherwise) to be on a specific port, something other than 53? I had built a custom ...
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  • 31
2 votes
2 answers
218 views

Does Kubernetes internal networking keep traffic to co-located Pods where possible?

In Kubernetes, if I run a Service Foo on every Node, and also Service Bar on every Node, i.e. with DaemonSets. If a Pod from Service Foo needs to make a request to Service Bar, does Kubernetes ...
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  • 141
2 votes
1 answer
64 views

Kubernetes container networking between pods

So I have a few services running using nodejs, in more than one kubernetes pod. These services obviously need to talk to each other, and be able to find the database included in this kubernetes ...
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  • 125
2 votes
1 answer
721 views

What do skipped, rescued, and ignored results mean in ANSIBLE playbook execution?

What do skipped, rescued, and ignored results mean in an Ansible playbook execution? What would be a possible scenario where these results would be different from 0? PLAY RECAP ************************...
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2 votes
2 answers
479 views

localhost Pod to Pod communication k8s

I am trying to transfer an old legacy system to k8s. I have a custom server that client apps connect to in order to communicate with one another. Both the server and clients were originally created ...
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  • 121
2 votes
1 answer
260 views

Check connectivity of 5000 + servers from ansible and get list of hosts which are connectable and which are not

I need to check connectivity of hosts on port 43. I can manually login and check connectivity by: nc -v `hostname` 43 nc -v `hostname_1` 43 Is there any ansible script that goes through all the ...
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2 votes
1 answer
911 views

aws - Connect two private subnets?

I'm testing some cloudformation infrastructure templates, and I noticed that most of the examples include routing tables to connect private subnets to public subnets, but my question then is: if two ...
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  • 143
2 votes
2 answers
1k views

Docker won't create a bridge network without being given an explicit subnet

The problem The problem is that this happens: $ docker network create alpine4 Error response from daemon: could not find an available, non-overlapping IPv4 address pool among the defaults to assign ...
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  • 121
2 votes
2 answers
1k views

Join a Linux Docker swarm with a local Windows Docker for test purposes

I'm currenlty trying to connect/join a Linux Docker Swarm cluster with my Windows machine in order to test a stack without sending the stack over and over to my test cluster under Linux. My problem is ...
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  • 213
2 votes
1 answer
650 views

Debug Docker DNS

In a stack with higher number of services it seems that Docker DNS does not work anymore which leads to effects that container's names are not known even to themselves. While I have filed this bug, I ...
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2 votes
1 answer
79 views

What parts of Kubernetes can have IP addresses?

Our network team says there an IP address in a subnet is being claimed and released seemingly at random. They are wondering if Kubernetes could be doing it. I know that Pods, Services and Nodes can ...
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  • 182
2 votes
1 answer
63 views

Why I cannot access k3s service from pod in rasbian?

I have installed K3S kubernetes on rasbian, and created a following mysql deployment on it: apiVersion: v1 kind: PersistentVolumeClaim metadata: name: mysql-data spec: accessModes: - ...
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2 votes
1 answer
99 views

phpMyAdmin using dockerised database

I have installed mariadb inside docker container, and mariadb is running properly inside that container. I want to get access of mariadb through phpMyAdmin from outside docker container. What will I ...
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2 votes
1 answer
385 views

How to access a container/service port in swarm without publishing the port to the outside world?

It is possible to docker-compose to forward a port to the container from localhost only, by writing the desired ports configure in docker-compose.yml, e.g. 127.0.0.1:8080:80. In docker swarm this does ...
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2 votes
0 answers
22 views

Connecting to MySQL Remotely on Azure VM

I am having trouble connecting remotely to my MySql install that runs on an Azure VM. Here is what I did: Ubuntu VM with MySql 5.7 installed Bind Address set to 0.0.0.0 User granted rights with ...
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  • 121
2 votes
1 answer
328 views

Docker: subnet clients can't ping other subnet

Two containers are created with this Dockerfile: FROM ubuntu:18.04 RUN apt update && apt upgrade -y && apt install -y vim iputils-ping net-tools tcpdump iproute* iptables traceroute ...
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  • 21
2 votes
0 answers
34 views

Weird behavior of the Docker Client on Windows 10 [closed]

There is an - as perceived - unsystematic behaviour of Docker client to setup an IPv6 connection to registry, even if this is disabled in daemon.json. Client error: dial tcp: lookup ******** on [::1]...
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1 vote
2 answers
45 views

Routing traffic from abc.com to xyz.com/abc

What is the most reliable way to route traffic from abc.com to xyz.com/abc? How does the server at xyz.com know for sure how to route the traffic to the /abc path? I understand that it might be a lot ...
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1 vote
1 answer
106 views

Sending HTTP requests to private EC2 DNS from other EC2 host works, but not from container on EC2 host

I want to make a container hosted on one EC2 host communicate with another container hosted on another EC2 host. Currently, if I send an HTTP request from host A to host B using host B's private DNS ...
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  • 123
1 vote
1 answer
7k views

External access to internet from Kubernetes Pods

I'm having troubles with network access from pods. I had installed new Kubernetes cluster with flannel-network plugin, Checking the health of server - good. I tried to check network via busybox: ...
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  • 41
1 vote
1 answer
257 views

Ansible cli_command loop register issues

I can't seem to get the register to works with cli_command and looping of multiples commands. Any suggestions? - name: Run show commands hosts: - all connection: network_cli gather_facts: ...
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  • 11
1 vote
1 answer
52 views

AWS Inspector "High Risk" : port open to the internet with IP whitelisting

We use AWS Inspector to identify risks with our AWS assets. Today I received a finding, with a "high" severity. The finding said that the FTP port was open to the internet. However, after ...
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  • 123
1 vote
1 answer
68 views

Docker container and their IPs on overlay (swarm) networks

I have a Docker overlay network which includes 2 containers and the loadbalancer for this network: "Containers": { "0ece6b958aa6b451478b5004ba1b1681ec91b718b99a0c2c88b79d5e8e135a66": { ...
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  • 629
1 vote
1 answer
107 views

How to create a local network mapping in linux

I'm deploying nextcloud via docker, however the way the configuration is set up, it creates a subnetwork at 10.10.10.0/24 on the system it's running on instead of running it on 127.0.0.1. Then the ...
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  • 21
1 vote
1 answer
508 views

Isolate service networks with Docker Compose

I have two containerised services, A and B, with which I wish to isolate network communications with docker compose. There is also a shared service C which is not isolated from A or B and is free to ...
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1 vote
1 answer
2k views

docker-compose up: Error starting userland proxy: listen tcp 0.0.0.0:443: bind: address already in use

specific error: ERROR: for traefik Cannot start service traefik: driver failed programming external connectivity on endpoint frappe_docker_traefik_1 (...
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1 vote
1 answer
52 views

How can I access port 80 of another container, when port 80 is already exposed?

I have a docker file that runs some integration tests between two containers. It looks a bit like this: version: '3' services: test_client: image: client:latest depends_on: ...
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  • 145
1 vote
1 answer
39 views

How to create a second IP just for dockers

Problem: my server is already using port 80 and I would like launch another service that uses port 80 on another address (I don't want to remember ports or force my wife to use non-default ports). I'...
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1 vote
1 answer
101 views

How do I setup an OpenShift route that will allow both 80 and 443 traffic to my app?

I'd like to setup a route that will pass both 80 and 443 traffic to the same service in OpenShift. When I try to create a second route it errors out. I want this to be in a yaml like would be used ...
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  • 273
1 vote
1 answer
87 views

Mapping Outbound IPs to 1 IP in Azure App Services

I have 3 components of my architecture running in 3 separate Azure App Services. Each app service has 4 outbound IPs. So whenever I have to deploy my app onto the client's premise, I have to whitelist ...
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1 vote
1 answer
53 views

Kubernetes: How to expose a Pod/Deployment to the Nodes Network

Ok, let's assume I've got the following theoretical setup: I want to somehow assign IP-Addresses accessible by the PCs on the left to my pods. I can set routes etc. as I need since this setup is ...
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1 vote
1 answer
648 views

Kubelet config file -- > clusterDNS

clusterDNS: - "10.32.0.10" The above is a flag passed to the kubelet file, i dont know what it refers to clsuter DNS ? Is it refers to VPC CIDR or any subnet CIDR ?
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1 vote
1 answer
284 views

Docker bridge network Configuration for containers

I have an Angular application deployed in the container . If I log in to the container I can curl to the port 4200. I have mapped to port 9001 to connect from my host . But I can't curl from my host ...
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  • 101
1 vote
1 answer
541 views

IOS_Command Module - Delayed Prompt Issue (Cisco 3850 - IOS XE)

I'm new to the Ansible world, so I'll do my best to explain everything. If I leave something out or need to clarify, just let me know. So, I've been working on upgrades for various Cisco switches/...
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1 vote
1 answer
272 views

How to perform low-level inspecting of a Docker network traffic?

I'm currently in a scenario that requires Docker container C to be able to intercept communication between docker containers A and B, without their knowledge. I am basically attempting to do a ...
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1 vote
1 answer
38 views

How to attach two (or more) networks to a container so they are available when the container starts?

I noticed if you try to attach a container to two networks, the following syntax does not cause an error, but effectively attach the container only on the network specified by the last --network: ...
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1 vote
1 answer
22 views

What are the benefits of spreading the various services of a multi-tiers application over several user-define bridges?

I have a simple system made of a database backend, several instances of a web application and a load balancer. Each service is running in its own Docker container, all of them being hosted on the same ...
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1 vote
1 answer
3k views

How to identify the physical IP of where Kubernetes API server runs

Question In a Kubernetes cluster, there is a Docker network IP which looks to be the API server. However, not sure how to identify the physical IP and location of the box in which it is working. If ...
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  • 363
1 vote
1 answer
1k views

Docker daemon error on joining swarm node - could not find local IP address - unknown port

Consider the following setup: Three hosts in the same network: Host A - SLES Host B - Ubuntu Host C - Ubuntu Then, the following has worked: Init swarm on A Join swarm at B, make B a manager The ...
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