How could I ping my docker container from my host
It works in this scenario:
- Windows host
- Linux VM installed on Windows host
- Docker container installed on Linux VM host
Now you have to note this. Containers are in a isolated network but connected to the internet throught your Docker container host adapter.So you have to tell kernel linux to be available in your network then in your Linux VM:
# sysctl net.ipv4.conf.all.forwarding=1
# sudo iptables -P FORWARD ACCEPT
Now in you Windows host you have to add a route for our container network: route add "Docker container network" "Linux VM IP" for example
# route add 172.17.0.0/16 192.168.1.20
You can't ping or access a container interface directly with Docker for Mac.
The current best solution is to connect to your containers from another container. At present there is no way we can provide routing to these containers due to issues with OSX that Apple have not yet resolved. we are tracking this requirement, but we cannot do anything about it at present.
Docker Toolbox/VirtualBox
When running Docker Toolbox, Docker Machine via VirtualBox or any VirtualBox VM (like a Vagrant definition) you can setup a "Host-Only Network" and access the Docker VMs network via that.
If you are using the default
boot2docker VM, don't change the existing interface as you will stop a whole lot of Docker utilities from working, add a new interface.
You will also need to setup routing from your Mac to the container networks via your VM's new IP address. In my case the Docker network range is 172.22.0.0/16
and the Host Only adapter IP on the VM is 192.168.99.100
.
sudo route add 172.22.0.0/16 192.168.99.100
Adding a permanent route to osx is bit more complex
Then you can get to containers from your Mac
machost:~ ping -c 1 172.22.0.2
PING 172.22.0.2 (172.22.0.2): 56 data bytes
64 bytes from 172.22.0.2: icmp_seq=0 ttl=63 time=0.364 ms
--- 172.22.0.2 ping statistics ---
1 packets transmitted, 1 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.364/0.364/0.364/0.000 ms
Vagrant + Ansible setup
Here's my running config...
Vagrant.configure("2") do |config|
config.vm.box = "debian/contrib-buster64"
config.vm.hostname = "docker"
config.vm.network "private_network", ip: "10.7.7.7", hostname: true
config.vm.provider "virtualbox" do |vb|
vb.gui = false
vb.memory = "4000"
vb.cpus = "4"
end
config.vm.provision "ansible" do |ansible|
ansible.verbose = "v"
ansible.playbook = "tasks.yaml"
end
end
The ansible tasks.yaml
to configure a fixed network.
- hosts: all
become: yes
vars:
ansible_python_interpreter: auto_silent
docker_config:
bip: 10.7.2.1/23
host: ["tcp://10.7.7.7:2375"]
userland-proxy: false
tasks:
- ansible.builtin.apt:
update_cache: yes
force_apt_get: yes
pkg:
- bridge-utils
- docker.io
- python3-docker
- python-docker
- iptables-persistent
- ansible.builtin.hostname:
name: docker
- ansible.builtin.copy:
content: "{{ docker_config | to_json }}"
dest: /etc/docker/daemon.json
- ansible.builtin.lineinfile:
line: 'DOCKER_OPTS="{% for host in docker_config.host %} -H {{ host }} {% endfor %}"'
regexp: '^DOCKER_OPTS='
path: /etc/default/docker
- ansible.builtin.systemd:
name: docker.service
state: restarted
- ansible.builtin.iptables:
action: insert
chain: DOCKER-USER
destination: 10.7.2.0/23
in_interface: eth1
out_interface: docker0
jump: ACCEPT
- ansible.builtin.shell: iptables-save > /etc/iptables/rules.v4
Add the route for the docker bridge network via the VM to the mac
$ sudo /sbin/route -n -v add -net 10.7.2.0/23 10.7.7.7
Then set DOCKER_HOST=10.7.7.7
in the environment to use the new VM.
$ export DOCKER_HOST=10.7.7.7
$ docker run --name route_test --rm -d node:14-slim node -e "require('http').createServer((req, res) => {
res.writeHead(200, {'Content-Type':'text/plain'})
res.end('hello')
}).listen(3000)"
$ docker container inspect route_test -f '{{ .NetworkSettings.Networks.bridge.IPAddress }}'
$ curl http://10.7.2.3:3000
hello
$ docker rm -f route_test
You don't get volumes mapped from the host to the vm, but as a bonus it uses a lot less cpu than the Docker 2.5.x release.
As an alternative, if your container has a bash shell incorporated, you can access it through
docker exec -it <CONTAINER ID> bash
and then you can ping your virtual ip