I am a beginner to docker.Please correct me if anything wrong.
As shown in this docker swarm tutorial https://www.youtube.com/watch?v=nGSNULpHHZc , i am trying to setup multhost setup for my hyperledger fabric application.
I am using two oracle linux servers namely server 1 and server 2.
I connected both the servers using the docker swarm as managers and created overlay network called my-net.
I followed the same syntax given in the above mentioned tutorial and created the service using the beolw mentioned syntax.
docker service create --name myservice --network my-net --replicas 2 alpine sleep 1d
As expected it created one conatianer in each the server.
Say for example server 1 coantainer IP is 10.0.0.4 and server 2 container IP 10.0.0.5.
Now, i am trying to ping from the second servers container to first server's container as shown below and it is pinging.
# docker exec -it ContainerID sh
/ # ping 10.0.0.4
PING 10.0.0.4 (10.0.0.4): 56 data bytes
64 bytes from 10.0.0.4: seq=0 ttl=64 time=0.082 ms
64 bytes from 10.0.0.4: seq=1 ttl=64 time=0.062 ms
64 bytes from 10.0.0.4: seq=2 ttl=64 time=0.067 ms
^C
--- 10.0.0.4 ping statistics ---
3 packets transmitted, 3 packets received, 0% packet loss
round-trip min/avg/max = 0.062/0.070/0.082 ms
Now, I am trying to create my service(1) using the beolw mentioned syntax.
docker service create --name myservice1 --network my-net --replicas 2 hyperledger/fabric-peer sleep 1d
As expected this also created one conatianer in each the server.
Say for example server 1 coantainer IP is 10.0.0.6 and server 2 container IP 10.0.0.7.
Now, I am trying to ping from the second servers container to first server's container as shown below.
This time i am getting ping not found error,
# docker exec -it ContainerID sh
# ping 10.0.0.6
sh: 1: ping: not found
Can anyone please help what is the problem with the second myservice1.
The Fabric Docker images are based on a bare bones base Ubuntu image and do not include utilities like ping. Once you "exec" into the peer containers, you use "apt" to install ping:
apt-get update
apt-get install inetutils-ping
Added -ping at the end
Expanding on Gari Singh's answer, on a Fabric network I've spun this week, the inetutils has been split in different packages:
# apt-cache search inetutils
inetutils-ftp - File Transfer Protocol client
inetutils-ftpd - File Transfer Protocol server
inetutils-inetd - internet super server
inetutils-ping - ICMP echo tool
inetutils-syslogd - system logging daemon
inetutils-talk - talk to another user
inetutils-talkd - remote user communication server
inetutils-telnet - telnet client
inetutils-telnetd - telnet server
inetutils-tools - base networking utilities (experimental pac
so to install e.g. ping the correct command has become:
# apt-get install inetutils-ping
The Ubuntu version of the peer is:
# cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=16.04
DISTRIB_CODENAME=xenial
DISTRIB_DESCRIPTION="Ubuntu 16.04.5 LTS"
Related
My host machine is MAC and I have installed Docker on my machine.
1.) Have downloaded the mysql:5 image and started container from the same :-
docker container run -d -e MYSQL_ROOT_PASSWORD=password -e MYSQL_DATABASE=learners --network bridge mysql:5
2.) Now I have logged into the Docker container, using the default bridge :-
(base) aditya#aditya-MAC PROJECTS % docker container exec -it c4 bash
root#c4abb2947a1f:/usr/local/bin#
root#c4abb2947a1f:/usr/local/bin#
root#c4abb2947a1f:/usr/local/bin# ping google.com
PING google.com (142.250.193.238) 56(84) bytes of data.
^C
--- google.com ping statistics ---
7 packets transmitted, 0 received, 100% packet loss, time 2090ms
root#c4abb2947a1f:/usr/local/bin#
root#c4abb2947a1f:/usr/local/bin#
3.) On my host machine, here are networks I have :-
(base) aditya#aditya-MAC ~ % docker network ls
NETWORK ID NAME DRIVER SCOPE
c0bcfcc8b9ac aditya-network bridge local
197c1cbd4534 bridge bridge local
e7b2d1393818 docker-hadoop_default bridge local
cf84498b715b host host local
69dd81905f0a ksql-course-master_default bridge local
c0c5220ade8f none null local
(base) B0218162#APB-LTB0218162-MAC ~ %
Inside my docker, I am able to install any package like apt-get install iputils-ping.
Any help shall be highly appreciated.
Update all Repos with command -> apt update
Install iputils with command -> apt install iputils-ping
This worked for my system so I guess it should work for you too.
I am trying to connect two locally developed projects running on docker-compose by using external networking.
From one side I have an 1st application intended to be exposed. Compose contains hosts: app and rabbit:
version: '3.4'
services:
app:
# ...
rabbit:
# ...
networks:
default:
driver: bridge
From other side I have second application expected to see 1st application:
version: '3.4'
services:
app:
# ...
networks:
- paymentservice_default
- default
networks:
paymentservice_default:
external: true
Reaching host rabbit.paymentservice_default is possible.
However service app (1st) conflicts with app (2nd):
root#6db86687229c:/app# ping app.paymentservice_default
PING app.paymentservice_default (192.168.80.6) 56(84) bytes of data.
root#6db86687229c:/app# ping app
PING app (192.168.80.6) 56(84) bytes of data.
In general from 2nd compose perspective hosts app and app.paymentservice_default shares same IP making app.paymentservice_default undiscoverable.
The question here is, do I have proper configuration and conflict can be avoided without changing service names app? Why this constraint? Taking consideration that every docker-compose configuration is shared across projects and can be developed in micro-services world.
$ docker-compose --version
docker-compose version 1.17.1, build unknown
$ docker --version
Docker version 19.03.4, build 9013bf583a
Thank you.
I use the following configuration on Docker Playground
paymentservice.docker-compose.yml
version: '3.4'
services:
app:
image: busybox
# keep container running
command: tail -f /dev/null
rabbit:
image: rabbitmq
networks:
default:
driver: bridge
other.docker-compose.yml
version: '3.4'
services:
app:
image: busybox
# keep container running
command: tail -f /dev/null
networks:
- paymentservice_default
- default
networks:
paymentservice_default:
external: true
Run both projects
$ COMPOSE_PROJECT_NAME=paymentservice docker-compose -f paymentservice.docker-compose.yml up -d
$ COMPOSE_PROJECT_NAME=other docker-compose -f other.docker-compose.yml up -d
Show Docker IPs
$ docker ps -q | xargs -n 1 docker inspect --format '{{ .Name }} {{range .NetworkSettings.Networks}} {{.IPAddress}}{{end}}' | sed 's#^/##';
I got
other_app_1 172.20.0.2 172.19.0.4
paymentservice_app_1 172.19.0.3
paymentservice_rabbit_1 172.19.0.2
and I pinged paymentservice_app_1 (172.19.0.3) from other_app_1 using app.paymentservice_default
$ docker exec -it other_app_1 ping -c 1 app.paymentservice_default
PING app.paymentservice_default (172.19.0.3): 56 data bytes
64 bytes from 172.19.0.3: seq=0 ttl=64 time=0.258 ms
--- app.paymentservice_default ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss
round-trip min/avg/max = 0.258/0.258/0.258 ms
and I pinged other_app_1 (172.20.0.2) from other_app_1 using app
$ docker exec -it other_app_1 ping -c 1 app
PING app (172.20.0.2): 56 data bytes
64 bytes from 172.20.0.2: seq=0 ttl=64 time=0.054 ms
--- app ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss
round-trip min/avg/max = 0.054/0.054/0.054 ms
As you can see, I can access the 1st app (of paymentservice.docker-compose.yml) from the 2nd app (of other.docker-compose.yml).
The same works in the other direction. I pinged other_app_1 (172.19.0.4) from paymentservice_app_1 using app.paymentservice_default
$ docker exec -it paymentservice_app_1 ping -c 1 app.paymentservice_default
PING app.paymentservice_default (172.19.0.4): 56 data bytes
64 bytes from 172.19.0.4: seq=0 ttl=64 time=0.198 ms
--- app.paymentservice_default ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss
round-trip min/avg/max = 0.198/0.198/0.198 ms
I pinged paymentservice_app_1 (172.19.0.3) from paymentservice_app_1 using app
$ docker exec -it paymentservice_app_1 ping -c 1 app
PING app (172.19.0.3): 56 data bytes
64 bytes from 172.19.0.3: seq=0 ttl=64 time=0.057 ms
--- app ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss
round-trip min/avg/max = 0.057/0.057/0.057 ms
As you can see, I can access app service of both projects. If I like to access the service of the same project, I use the default network of the project. If I'd like to access the service of another project, I use the external network shared between both projects.
Note: I would recommend to make this more explicit by creating the shared network outside of the projects using the command line
docker network create shared-between-paymentservice-and-other
and declaring it as external in both projects.
Note: There is still the limitation that service discovery may not work if you have 3 projects with the same service name (e.g. app) in the same (external) network (sort of a namespace). In that case, it might be a better idea to rename your services, use multiple external networks, define aliases or use a totally different approach to discover/identify the Docker containers.
Afterword
Has that been the requirement? I tried to reproduce your issue, but I'm not sure if I did the same as you. For example, I'm not sure, where you are running ping. Is root#6db86687229c the Docker host or a Docker container? Which container? I assumed it is the Docker container of service app of other.docker-compose.yml. Please comment if I'm missing something or misinterpreted your question and I will update my answer. Then I may explain in more detail or make another suggestion how to do service discovery between multiple Docker Compose projects.
Appendix
Cleanup
$ COMPOSE_PROJECT_NAME=other docker-compose -f other.docker-compose.yml down
$ COMPOSE_PROJECT_NAME=paymentservice docker-compose -f paymentservice.docker-compose.yml down
Versions
$ docker --version
Docker version 20.10.0, build 7287ab3
$ docker-compose --version
docker-compose version 1.26.0, build unknown
I solved it, se the edit at the end of the description.
I'm using Centos7 as a host and running docker version 17.05.0-ce
I'm able to pull images on to the host.
from inside a contiainer I'm able to ping the docker interface, I'm also able to ping the host machine. But thats it, I'm not able to ping any other hosts, not the dns on the local network, not google, nothing. I guess it's something with the routing, but I can't figure it out.
Anyone got an idea?
This is (obviously) not about connecting to other containers on the same host. but probably a problem with the routing or configuration in docker
jonmat ~ $ docker -v
Docker version 17.05.0-ce, build 89658be
# pulling images works fine, so the engine can connect to the internet
jonmat ~ $ docker pull alpine
Using default tag: latest
latest: Pulling from library/alpine
ff3a5c916c92: Pull complete
Digest: sha256:7b848083f93822dd21b0a2f14a110bd99f6efb4b838d499df6d04a49d0debf8b
Status: Downloaded newer image for alpine:latest
# pinging google dns from the host is is no problem
jonmat ~ $ ping -c1 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=56 time=5.16 ms
--- 8.8.8.8 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 5.160/5.160/5.160/0.000 ms
# pinging google dns from inside the container won't work, probably some kind of routing issue?
jonmat ~ $ docker run -it --rm alpine ping -c1 8.8.8.8
PING 8.8.8.8 (8.8.8.8): 56 data bytes
--- 8.8.8.8 ping statistics ---
1 packets transmitted, 0 packets received, 100% packet loss
EDIT:
I found the problem myself. someone other than me have also been using the host, and they added the option "--ptables=false" to dockerd, i removed this and it solved my problem.
Assuming your container is running with name alpine, can you try below command
docker exec -t alpine ping 8.8.8.8
In the example given above, seems you are missing some options, try this
docker run -it --rm -t alpine ping -c1 8.8.8.8
If container is already running use docker exec like posted above. (I would like to combine both answers, but unfortunately I am not finding option to delete and add it in the first answer itself)
Refer the docker exec for more details
I am looking for a solution to ping a Docker container using its hostname, from another Docker Container.
I tried as follow:
starting first Docker container:
docker run --rm -ti --hostname=repohost --name=repo repo
starting second Docker container, link to first and start bash:
docker run --rm -ti --hostname=repo2host --link repo:rp repo2 /bin/bash
on bash started on repo2
ping repohost
it remain on pending without any result.
Can someone tell me if there is a solution for this?
You should be able to ping using the alias you gave in the link command (the part after the :), in your case ping rp should work.
The following works for me, given a running container called furious_turing:
$ docker run -it --link furious_turing:ft debian /bin/bash
root#06b18931d80b:/# ping ft
PING ft (172.17.0.3): 48 data bytes
56 bytes from 172.17.0.3: icmp_seq=0 ttl=64 time=0.136 ms
56 bytes from 172.17.0.3: icmp_seq=1 ttl=64 time=0.091 ms
56 bytes from 172.17.0.3: icmp_seq=2 ttl=64 time=0.092 ms
^C--- ft ping statistics ---
3 packets transmitted, 3 packets received, 0% packet loss
round-trip min/avg/max/stddev = 0.091/0.106/0.136/0.000 ms
root#06b18931d80b:/#
If you need to ping on another name, you can add entries to /etc/hosts with the --add-host argument to docker run.
One way to achieve what you need would be with WeaveDNS.
I'm trying to configure fig so that I can connect to my database server without specifying a fully qualified domain name. The database is running on bare metal (not in docker). On the host, glinda.local is specified in /etc/hosts and I'd like the container to mimic this behavior (though not rely on the host's config).
I found this suggestion on github, but it fails since /etc/hosts is on a read-only file system.
So the question remains, how can I add glinda.local from fig.yml to /etc/hosts inside my docker container?
From Docker v1.3.1 (I think) you have available the option --add-host in docker run. Unfortunately this options has not been merged to fig:master yet, but there is a PR with it. When merged (or using that branch) you should be able to use it in this way:
extra_hosts
Add hostname mappings. Use the same values as the docker client
--add-hosts parameter.
> extra_hosts:
> - docker: 162.242.195.82
> - fig: 50.31.209.229
An entry with the ip address and hostname will be created in
/etc/hosts inside containers for this service, e.g:
> 162.242.195.82 docker
> 50.31.209.229 fig
What makes you think /etc/hosts is read-only? The following works for me with Docker 1.5:
$ docker run -it debian
root#0989fd55e8fa:/# echo "127.0.0.1 test" >> /etc/hosts
root#0989fd55e8fa:/# ping test
PING test (127.0.0.1): 48 data bytes
56 bytes from 127.0.0.1: icmp_seq=0 ttl=64 time=0.078 ms
56 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.068 ms
^C--- test ping statistics ---
2 packets transmitted, 2 packets received, 0% packet loss
round-trip min/avg/max/stddev = 0.068/0.073/0.078/0.000 ms
Are you saying this doesn't work for you? If the above works, you should be able to add what you need into an entrypoint script.