Docker ping ipv6 endpoint - docker

Question

I have a docker heartbeat container up and running from where a connection should be made towards an ipv6 endpoint.
From in the heartbeat container the ping6 command doesn't succeed, from on the host it is working.
In container
sh-4.2$ ping6 ipv6.google.com
PING ipv6.google.com(ams15s32-in-x0e.1e100.net (2a00:1450:400e:809::200e)) 56 data bytes
^C
on vm
[root#myserver myuser]# ping6 ipv6.google.com
PING ipv6.google.com(ams15s30-in-x0e.1e100.net (2a00:1450:400e:807::200e)) 56 data bytes
64 bytes from ams15s30-in-x0e.1e100.net (2a00:1450:400e:807::200e): icmp_seq=1 ttl=120 time=6.55 ms
64 bytes from ams15s30-in-x0e.1e100.net (2a00:1450:400e:807::200e): icmp_seq=2 ttl=120 time=6.60 ms
I've configured the daemon.json file with the subnet and the docker-compose file takes care of the preparation of the ipv6 network
version: "2.2"
services:
heartbeat:
image: docker.elastic.co/beats/heartbeat:7.10.1
container_name: "heartbeat"
volumes:
- "./elastic/heartbeat.yml:/usr/share/heartbeat/heartbeat.yml:ro"
- "./elastic/monitor.d/:/usr/share/heartbeat/monitor.d/:ro"
networks:
- beats
networks:
beats:
enable_ipv6: true
driver: bridge
ipam:
driver: default
config:
- subnet: 2a02:1800:1e0:408f::806:0/112
- gateway: 2a02:1800:1e0:408f::806:1
The docker network ls shows the network correctly setup
docker network ls
NETWORK ID NAME DRIVER SCOPE
...
328408216a9f deployments_beats bridge local
...
And the bridged network is appearing in the ifconfig overview with following info
br-328408216a9f: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 172.19.0.1 netmask 255.255.0.0 broadcast 172.19.255.255
inet6 2a02:1800:1e0:408f::806:1 prefixlen 112 scopeid 0x0<global>
inet6 fe80::1 prefixlen 64 scopeid 0x20<link>
inet6 fe80::42:52ff:fe98:e176 prefixlen 64 scopeid 0x20<link>
ether 02:42:52:98:e1:76 txqueuelen 0 (Ethernet)
RX packets 8 bytes 656 (656.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 7 bytes 746 (746.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
Anything I've missed during the setup?

Answer 1

You also need to enable ipv6 on the docker engine:
Edit /etc/docker/daemon.json, set the ipv6 key to true and the fixed-cidr-v6 key to your IPv6 subnet. In this example we are setting
it to 2001:db8:1::/64.
{
"ipv6": true,
"fixed-cidr-v6": "2001:db8:1::/64"
}
Save the file.
Reload the Docker configuration file.
$ systemctl reload docker
https://docs.docker.com/config/daemon/ipv6/

Answer 2

Solved by using https://github.com/robbertkl/docker-ipv6nat
Added the container to my docker setup
my daemon.json file in /etc/docker/
{
"ipv6": true,
"fixed-cidr-v6": "fd00::/64"
}
which will use the unique local subnet
in my docker-compose I create a ipv6 network
networks:
beats:
enable_ipv6: true
driver: bridge
ipam:
driver: default
config:
- subnet: fd00:1::/80
note the prefix 1 I'm using in the range
add your container to the network, and it works