I have a problem with all my docker containers, they don't has internet access, cannot reach external resources. Im using centos7 and I had installed CSF (configserver firewall) with the docker=1 setting.
I made a test using the next command:
docker run -itd --name=alpine1 alpine
then I enter to it using the next command:
docker exec -it alpine1 /bin/sh
inside the container I try to ping google
ping google.com
but I only get the next error message:
ping: bad address 'google.com'
But if I run the command:
docker run -itd --network host --name=alpine1 alpine
now i can ping google.com and get a success response:
PING google.com (2a00:1450:400f:804::200e): 56 data bytes
64 bytes from 2a00:1450:400f:804::200e: seq=0 ttl=119 time=6.741 ms
64 bytes from 2a00:1450:400f:804::200e: seq=1 ttl=119 time=6.836 ms
64 bytes from 2a00:1450:400f:804::200e: seq=2 ttl=119 time=6.842 ms
I think the solution not is run all the containers over host network, and this not apply to container using docker-compose
Any idea to fix that without using --network host?
thanks in advance
Related
If we create a container in default bridge network, we are able to access internet from within this container. (Below example copied from Networking with Standalone containers)
docker run -dit --name alpine1 alpine ash
docker attach alpine1
# ping -c 2 google.com
PING google.com (172.217.3.174): 56 data bytes
64 bytes from 172.217.3.174: seq=0 ttl=41 time=9.841 ms
64 bytes from 172.217.3.174: seq=1 ttl=41 time=9.897 ms
--- google.com ping statistics ---
2 packets transmitted, 2 packets received, 0% packet loss
round-trip min/avg/max = 9.841/9.869/9.897 ms
pinging google.com from within the container, we see successful ping response.
This behaviour seems to contradict the statement from Docker docs. Or I am not understanding something here ?
Link to Docker docs
Based on #Turing85's comment , I was checking if IPForwarding is enabled on my windows. Used this link How to enable IP forwarding in windows. Looks like its not enabled.
In my Fedora 32 machine DNS is working better. DNS lookup is working when ping google.com.
PING google.com (172.217.160.174) 56(84) bytes of data.
64 bytes from bom05s12-in-f14.1e100.net (172.217.160.174): icmp_seq=1 ttl=117 time=41.5 ms
64 bytes from bom05s12-in-f14.1e100.net (172.217.160.174): icmp_seq=2 ttl=117 time=47.2 ms
I build following simple docker image using default bridge network. (I need bridge network. My issue is working when i using host network. And DockerImage will have more commands)
FROM tailor/docker-libvips:node-10.9
docker build --tag dinuka/video-file-service-test-sandbox:node-10.9 .
docker run -dit --name video-test-1 dinuka/video-file-service-test-sandbox:node-10.9
I have logged to the container using following command.
docker attach video-test-1
After that i have tried to ping an IP. It is success.
/# ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=116 time=42.5 ms
But it is not working to domain
/# ping google.com
ping: google.com: Temporary failure in name resolution
The container DNS is correct. It is same as my machine name server.
/# cat /etc/resolv.conf
# Generated by NetworkManager
nameserver 192.168.1.1
My machine OS is Fedora 32. I have disable selinux and firewalld. I have tried many solutions in stackoverflow. But any can't solve this.
You need to manually add masquerading to the network interface:
ZONE=$(sudo firewall-cmd --get-zone-of-interface=<internet facing interface>)
sudo firewall-cmd --zone=$ZONE --add-masquerade --permanent success
sudo firewall-cmd --reload success
sudo systemctl restart docker
I'm having issues getting data sent into a statsd container. I can successfully send data while on the command line inside the container itself. I need to be able to send statistic data to it from the host machine or from another Docker container.
I'm using Kitematic, I can see that the selection for 'bridge' network is checked on both containers. Using a bridge network was a suggestion I found for this issue.
I also tried passing '-P' to Docker while running the command to build the container, as that was supposed to expose the ports. I didn't notice a difference in the way it behaved when sending data from the other container.
Example of code that runs to create fake statistics using port 8125 on localhost (taken from this Docker container webpage https://hub.docker.com/r/graphiteapp/graphite-statsd)
Let's fake some stats with a random counter to prove things are working.
while true; do echo -n "example:$((RANDOM % 100))|c" | nc -w 1 -u 127.0.0.1 8125; done
The container is created using the following command:
docker run -d --name graphite --restart=always -p 80:80 -p 2003-2004:2003-2004 -p 2023-2024:2023-2024 -p 8125:8125/udp -p 8126:8126 graphiteapp/graphite-statsd
I've tried making sure both are on the same 'bridge' network. I'm running Docker Desktop on Windows 10 Enterprise. I've found several commands dealing with iptables and networking on Linux, but I feel like I'm missing something. I might also mention that statsd uses UDP connection on port 8125 by default.
If I try running the example command from another container on the bridge network, I don't get any result. I know the data (from another container) is not getting over correctly because I can't see it in the metrics that get received on the statsd dashboard.
I can ping localhost:8125 and get a response from within another container. From the outside (Powershell window on the host machine) it won't resolve.
PING localhost:8125 (127.0.0.1): 56 data bytes
64 bytes from 127.0.0.1: seq=0 ttl=64 time=0.024 ms
64 bytes from 127.0.0.1: seq=1 ttl=64 time=0.052 ms
64 bytes from 127.0.0.1: seq=2 ttl=64 time=0.031 ms
^C
--- localhost:8125 ping statistics ---
3 packets transmitted, 3 packets received, 0% packet loss
round-trip min/avg/max = 0.024/0.035/0.052 ms>
If I run docker container ls then I get the following:
I found that I needed to get the specific IP address for each container, which can be found by running docker inspect (name of network). In this case, bridge.
Then I needed to specify the IP address of the container. I replaced the suggested address with that IP address and it worked.
I am trying to access devices on my network with .local domain, but it doesn't seem to work in Docker.
Ping from host is working:
$ ping test1.local
PING test1.local (192.168.1.90) 56(84) bytes of data.
64 bytes from 192.168.1.90 (192.168.1.90): icmp_seq=1 ttl=255 time=1.41 ms
64 bytes from 192.168.1.90 (192.168.1.90): icmp_seq=2 ttl=255 time=1.54 ms
Docker demon config:
$ cat /etc/docker/daemon.json
{
"dns": ["192.168.1.1","8.8.8.8"]
}
If I try to ping test1.local from Docker:
$ sudo docker run --network host busybox ping -c 3 test1.local
ping: bad address 'test1.local'
Pinging device with IP works:
$ sudo docker run --network host busybox ping -c 3 192.168.1.90
PING 192.168.1.90 (192.168.1.90): 56 data bytes
64 bytes from 192.168.1.90: seq=0 ttl=255 time=4.855 ms
64 bytes from 192.168.1.90: seq=1 ttl=255 time=1.566 ms
So I assume something is wrong name resolution.
madrian#ubuntudev:~$ cat /etc/resolv.conf
$ cat /etc/resolv.conf
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
# 127.0.0.53 is the systemd-resolved stub resolver.
# run "systemd-resolve --status" to see details about the actual nameservers.
nameserver 127.0.0.1
search localdomain
Any ideas how to resolve this issue?
Try run your code without --network host argument. The problem is in the DNS resolution.
When you use default bridge (which will be used if you omit network parameter), containers inherit DNS configuration from host, and that is what you need:
https://docs.docker.com/v17.09/engine/userguide/networking/default_network/configure-dns/
When you use user-defined bridge, Docker updates DNS records to enable seamless communication between containers by their names:
https://docs.docker.com/v17.09/engine/userguide/networking/configure-dns/
Unfortunately, I was unable to find explicit explanation on how DNS works with host mode, so I assume this is a problem
I have a CentOS 7 host on which I am running Docker. When I do a ping from my host to 8.8.8.8, ping was successful whereas same inside a docker container is not working.
From Host
[root#linux1 ~]# ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=47 time=31.5 ms
64 bytes from 8.8.8.8: icmp_seq=2 ttl=47 time=31.6 ms
^C
--- 8.8.8.8 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1001ms
rtt min/avg/max/mdev = 31.592/31.617/31.643/0.179 ms
From Docker Container (I am using basic ubuntu image):
[root#linux1 ~]# docker run ubuntu ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
From 172.17.0.1 icmp_seq=1 Destination Host Unreachable
From 172.17.0.1 icmp_seq=2 Destination Host Unreachable
From 172.17.0.1 icmp_seq=3 Destination Host Unreachable
From 172.17.0.1 icmp_seq=4 Destination Host Unreachable
^C
--- 8.8.8.8 ping statistics ---
6 packets transmitted, 0 received, +4 errors, 100% packet loss, time 5000ms
pipe 4
Any suggestions would be helpful. Thanks
Restart the Docker daemon on Debian9
service docker restart
and the connections and networks works fine
Recently I faced a similar network issue. The other answers here didn't help: DNS was working fine and restarting Docker wouldn't change a thing. I've found that specifying the network as host solved it.
There are three ways of doing it:
In docker-compose:
By setting network_mode in the yaml file:
services:
worker:
build: .
network_mode: host
In the image building stage for RUN commands:
docker build --network=host
In the execution stage for the application:
docker run --network=host <image>
Try this:
docker run --dns=8.8.8.8 -it ubuntu ping 8.8.8.8
Ref: DOCKER DNS
I figured out the issue. It is not an issue with the DNS but an issue with the network connection itself inside Docker containers. Drilled down the issue is the default IP assigned to docker0 interface, which conflicted with my network address. Forced docker daemon to assign an IP so that it won't conflict and my issue is resolved.
Thanks
I had the same issue when stop and start container separately. I have just rebuild and re up containers.
docker-compose down
docker-compose build
docker-compose up -d
And then problem gone.