I'm setting up a docker swarm deployment across two hosts: one linux and one windows. For some reason my containers cannot see (eg. ping) each other when they are deployed on different hosts. I have tried using plain wsl2 docker and docker via docker desktop with wsl2 as the backend. However, if I use two linux hosts (instead of one being windows), my containers can see each other without problems.
I set up my network like this:
networks:
mtmsnetwork:
ipam:
config:
- subnet: 172.30.0.0/16
And then I add both of my services to this network:
networks:
mtmsnetwork:
Is there some additional configuration I should make?
Related
The goal: To deploy on docker swarm a set of services, one of which is only available for me when I am connected to the OpenVPN server which has also been spun up on docker swarm.
How can I, step by step, only connect to a whoami example container, with a domain in the browser, when I am connected to a VPN?
Background
The general idea would be have, say, kibana and elasticsearch running internally which can only be accessed when on the VPN (rather like a corporate network), with other services running perfectly fine publicly as normal. These will all be on separate nodes, so I am using an overlay network.
I do indeed have OpenVPN running on docker swarm along with a whoami container, and I can connect to the VPN, however it doesn't look like the IP is changing and I have no idea how to make it so that the whoami container is only available when on the VPN, especially considering I'm using an overlay network which is multi-host. I'm also using traefik, a reverse proxy which provides me with a mostly automatic letsencrypt setup (via DNS challenge) for wildcard domains. With this I can get:
https://traefik.mydomain.com
But I also want to connect to vpn.mydomain.com (which I can do right now), and then be able to visit:
https://whoami.mydomain.com
...which I cannot. Yet. I've posted my traefik configuration in a different place in case you want to take a look, as this thread will grow too big if I post it here.
Let's start with where I am right now.
OpenVPN
Firstly, the interesting thing about OpenVPN and docker swarm is that OpenVPN needs to run in privileged mode because it has to make network interfaces changes amongst other things, and swarm doesn't have CAP_ADD capabilities yet. So the idea is to launch the container via a sort of 'proxy container' that will run the container manually with these privileges added for you. It's a workaround for now, but it means you can deploy the service with swarm.
Here's my docker-compose for OpenVPN:
vpn-udp:
image: ixdotai/swarm-launcher:latest
hostname: mainnode
environment:
LAUNCH_IMAGE: ixdotai/openvpn:latest
LAUNCH_PULL: 'true'
LAUNCH_EXT_NETWORKS: 'app-net'
LAUNCH_PROJECT_NAME: 'vpn'
LAUNCH_SERVICE_NAME: 'vpn-udp'
LAUNCH_CAP_ADD: 'NET_ADMIN'
LAUNCH_PRIVILEGED: 'true'
LAUNCH_ENVIRONMENTS: 'OVPN_NATDEVICE=eth1'
LAUNCH_VOLUMES: '/etc/openvpn:/etc/openvpn:rw'
volumes:
- '/var/run/docker.sock:/var/run/docker.sock:rw'
networks:
- my-net
deploy:
placement:
constraints:
- node.hostname==mainnode
I can deploy the above with: docker stack deploy --with-registry-auth --compose-file docker/docker-compose.prod.yml my-app-name and this is what I'm using for the rest. Importantly I cannot just deploy this as it won't load yet. OpenVPN configuration needs to exist in /etc/openvpn on the node, which is then mounted in the container, and I do this during provisioning:
// Note that you have to create the overlay network with --attachable for standalone containers
docker network create -d overlay app-net --attachable
// Create the config
docker run -v /etc/openvpn:/etc/openvpn --log-driver=none --rm ixdotai/openvpn ovpn_genconfig -u udp://vpn.mydomain.com:1194 -b
// Generate all the vpn files, setup etc
docker run -v /etc/openvpn:/etc/openvpn --log-driver=none --rm ixdotai/openvpn bash -c 'yes yes | EASYRSA_REQ_CN=vpn.mydomain.com ovpn_initpki nopass'
// Setup a client config and grab the .ovpn file used for connecting
docker run -v /etc/openvpn:/etc/openvpn --log-driver=none --rm ixdotai/openvpn easyrsa build-client-full client nopass
docker run -v /etc/openvpn:/etc/openvpn --log-driver=none --rm ixdotai/openvpn ovpn_getclient client > client.ovpn
So now, I have an attachable overlay network, and when I deploy this, OpenVPN is up and running on the first node. I can grab a copy of client.ovpn and connect to the VPN. Even if I check "send all traffic through the VPN" though, it looks like the IP isn't being changed, and I'm still nowhere near hiding a container behind it.
Whoami
This simple container can be deployed with the following in docker-compose:
whoami:
image: "containous/whoami"
hostname: mainnode
networks:
- ${DOCKER_NETWORK_NAME}
ports:
- 1337:80
deploy:
placement:
constraints:
- node.hostname==mainnode
I put port 1337 there for testing, as I can visit my IP:1337 and see it, but this doesn't achieve my goal of having whoami.mydomain.com only resolving when connected to OpenVPN.
I can ping a 192.168 address when connected to the vpn
I ran the following on the host node:
ip -4 address add 192.168.146.16/24 dev eth0
Then when connected to the VPN, I can resolve this address! So it looks like something is working at least.
How can I achieve the goal stated at the top? What is required? What OpenVPN configuration needs to exist, what network configuration, and what container configuration? Do I need a custom DNS solution as I suggest below? What better alternatives are there?
Some considerations:
I can have the domains, including the private one whoami.mydomain.com public. This means I would have https and get wildcard certificates for them easily, I suppose? But my confusion here is - how can I get those domains only on the VPN but also have tls certs for them without using a self-signed certificate?
I can also run my own DNS server for resolving. I have tried this but I just couldn't get it working, probably because the VPN part isn't working properly yet. I found dnsmasq for this and I had to add the aforementioned local ip to resolve.conf to get anything working locally for this. But domains would still not resolve when connected to the VPN, so it doesn't look like DNS traffic was going over the VPN either (even though I set it as such - my client is viscosity.
Some mention using a bridge network, but a bridge network does not work for multi-host
Resources thus far (I will update with more)
- Using swarm-launcher to deploy OpenVPN
- A completely non-explanatory answer on stackexchange which I have seen referenced as basically unhelpful by multiple people across other Github threads, and one of the links is dead
So I was banging my head head against a brick wall about this problem and just sort of "solved" it by pivoting your idea:
Basically I opened the port of the vpn container to its host. And then enable a proxy. This means that I can reach that proxy by visiting the ip of the pc in which the vpn resides (AKA the Docker Host of the VPN container/stack).
Hang with me:
I used gluetun vpn but I think this applies also if you use openvpn one. I just find gluetun easier.
Also IMPORTANT NOTE: I tried this in a localhost environment, but theoretically this should work also in a multi-host situation since I'm working with separated stacks. Probably, in a multi-host situation you need to use the public ip of the main docker host.
1. Create the network
So, first of all you create an attachable network for this docker swarm stacks:
docker network create --driver overlay --attachable --scope swarm vpn-proxy
By the way, I'm starting to think that this passage is superfluous but need to test it more.
2. Set the vpn stack
Then you create your vpn stack file, lets call it stack-vpn.yml:
(here I used gluetun through swarm-launcher "trick". This gluetun service connects through a VPN via Wireguard. And it also enables an http proxy at the port 8888 - this port is also mapped to its host by setting LAUNCH_PORTS: '8888:8888/tcp')
version: '3.7'
services:
vpn_launcher:
image: registry.gitlab.com/ix.ai/swarm-launcher
volumes:
- '/var/run/docker.sock:/var/run/docker.sock:rw'
networks:
- vpn-proxy
environment:
LAUNCH_IMAGE: qmcgaw/gluetun
LAUNCH_PULL: 'true'
LAUNCH_EXT_NETWORKS: 'vpn-proxy'
LAUNCH_PROJECT_NAME: 'vpn'
LAUNCH_SERVICE_NAME: 'vpn-gluetun'
LAUNCH_CAP_ADD: 'NET_ADMIN'
LAUNCH_ENVIRONMENTS: 'VPNSP=<your-vpn-service> VPN_TYPE=wireguard WIREGUARD_PRIVATE_KEY=<your-private-key> WIREGUARD_PRESHARED_KEY=<your-preshared-key> WIREGUARD_ADDRESS=<addrs> HTTPPROXY=on HTTPPROXY_LOG=on'
LAUNCH_PORTS: '8888:8888/tcp'
deploy:
placement:
constraints: [ node.role == manager ]
restart_policy:
condition: on-failure
networks:
vpn-proxy:
external: true
Notice that either the swarm-launcher and the gluetun containers are using the network previously created vpn-proxy.
3. Set the workers stack
For the time being we will set an example with 3 replicas of alpine image here (filename stack-workers.yml):
version: '3.7'
services:
alpine:
image: alpine
networks:
- vpn-proxy
command: 'ping 8.8.8.8'
deploy:
replicas: 3
networks:
vpn-proxy:
external: true
They also use the vpn-proxy overlay network.
4. Launch our stacks
docker stack deploy -c stack-vpn.yml vpn
docker stack deploy -c stack-workers workers
Once they are up you can access any worker task and try to use the proxy by using the host ip where the proxy resides.
As I said before, theoretically this should work on a multi-host situation, but probably you need to use the public ip of the main docker host (although if they share the same overlay network it could also work with the internal ip address (192...) ).
I have a prototype that sends information to the host machine, and with Docker for Windows, the container grabs that information and everything works fine.
My docker-compose.yml file:
version: '3'
services:
middleware:
container_name: middleware
image: hyperloopupv:middleware
build: './receta'
ports:
- "5672:5672"
- "15672:15672"
- "1338:1338/udp"
- "5556:5556/udp"
But others from my team are using Docker Toolbox, and Docker Toolbox can not use localhost. I have tried to send the information from the prototype to the IP of the container(192.168.99.100), but the packets are lost.
Is there a way, that my team(using Docker Toolbox) and I(using Docker for Windows) can get this running without problems with the same compose file?
Thanks
Docker Desktop and Toolbox are completely different products. Docker Desktop runs on Hyper-V, Docker Toolbox on Virtualbox. Desktop is the actual product, Toolbox is the “legacy desktop solution”.
It is possible to manipulate its IP address. If you look a the docs under ‘Options’ you find an option called virtualbox-hostonly-cidr that you can use to manipulate the IP address when you create a new machine. But before you try this notice that it is called ‘hostonly’. This means it uses the Virtualbox Host-Only adapter and “the virtual machines cannot talk to the world outside the host since they are not connected to a physical networking interface” (from the Virtualbox docs).
So unfortunately it seems there is no simple solution to your problem.
I learned from docker documentation that I can not use docker DNS to find containers using their hostnames without utilizing user-defined bridge network. I created one using the command:
docker network create --driver=overlay --subnet=172.22.0.0/16 --gateway=172.22.0.1 user_defined_overlay
and tried to deploy a container that uses it. compose file looks like:
version: "3.0"
services:
web1:
image: "test"
ports:
- "12023:22"
hostname: "mytest-web1"
networks:
- test
web2:
image: "test"
ports:
- "12024:22"
hostname: "mytest-web2"
networks:
- test
networks:
test:
external:
name: user_defined_overlay
my docker version is: Docker version 17.06.2-ce, build cec0b72
and I got the following error when I tried deploying the stack:
network "user_defined_bridge" is declared as external, but it is not in the right scope: "local" instead of "swarm"
I was able to create an overlay network and define it in compose file. that worked fine but it didn't for bridge.
result of docker network ls:
NETWORK ID NAME DRIVER SCOPE
cd6c1e05fca1 bridge bridge local
f0df22fb157a docker_gwbridge bridge local
786416ba8d7f host host local
cuhjxyi98x15 ingress overlay swarm
531b858419ba none null local
15f7e38081eb user_defined_overlay overlay swarm
UPDATE
I tried creating two containers running on two different swarm nodes(1st container runs on manager while second runs on worker node) and I specified the user-defined overlay network as shown in stack above. I tried pinging mytest-web2 container from within mytest-web1 container using hostname but I got unknown host mytest-web2
As of 17.06, you can create node local networks with a swarm scope. Do so with the --scope=swarm option, e.g.:
docker network create --scope=swarm --driver=bridge \
--subnet=172.22.0.0/16 --gateway=172.22.0.1 user_defined_bridge
Then you can use this network with services and stacks defined in swarm mode. For more details, you can see PR #32981.
Edit: you appear to have significantly overcomplicated your problem. As long as everything is being done in a single compose file, there's no need to define the network as external. There is a requirement to use an overlay network if you want to communicate container-to-container. DNS discovery is included on bridge and overlay networks with the exception of the default "bridge" network that docker creates. With a compose file, you would never use this network without explicitly configuring it as an external network with that name. So to get container to container networking to work, you can let docker-compose or docker stack deploy create the network for your project/stack automatically with:
version: "3.0"
services:
web1:
image: "test"
ports:
- "12023:22"
web2:
image: "test"
ports:
- "12024:22"
Note that I have also removed the "hostname" setting. It's not needed for DNS resolution. You can communicate directly with a service VIP with the name "web1" or "web2" from either of these containers.
With docker-compose it will create a default bridge network. Swarm mode will create an overlay network. These defaults are ideal to allow DNS discovery and container-to-container communication in each of the scenarios.
The overlay network is the network to be used in swarm. Swarm is meant to be used to manage containers on multiple hosts and overlay networks are docker's multi-host networks https://docs.docker.com/engine/userguide/networking/get-started-overlay/
Can anyone shed some light on what is what with the Docker Compose YML file?
All I want to do is to be able to control the IP addresses of the various containers. I am using version 3.1 (but also tried 3.3 as I recently upgraded to version 17.06). The documentation says:
A full example:
ipam:
driver: default
config:
- subnet: 172.28.0.0/16
Note: Additional IPAM configurations, such as gateway, are only honored for version 2 at the moment.
When I do this, I need that subnet honored when I inspect the network. However the gateway is completely different [read the Note: above], so the containers do not start. Why did they lose capability (at the moment) in version 3 for something that worked in version 2? Worse, why wasn't that restored in version 3.2 or 3.3?
Maybe I am way off base here - certainly wouldn't be first time! What is most important to me: is there a way to modify a compose file to allow a docker stack deploy command (in a Docker Swarm) to provide control of the gateway and subnets used?
Finally figured this out and I am posting what I did in the hopes that it might help someone else. While I did not know this when I started, what I really wanted [needed? :) ] to do was to redefine the default settings of the docker_gwbridge network.
This is how I did that:
docker swarm init # I am assuming this was already done, this creates the network with default settings
docker swarm leave -f # only if you did an 'init'
docker network ls # just to see the docker_gwbridge network
docker network rm docker_gwbridge
# if you never created/initialized a swarm, you can start here
SUBNET=172.19.0.0/16 # my defaults were always 172.18, using 19 only to test that this works
GATEWAY=172.19.0.1
docker network create --subnet=$SUBNET --gateway $GATEWAY \
-o com.docker.network.bridge.name=docker_gwbridge \
-o com.docker.network.bridge.enable_icc=false \
-o com.docker.network.bridge.enable_ip_masquerade=true \
docker_gwbridge
docker swarm init # now start the swarm
docker network inspect docker_gwbridge # if you want to see your changes
docker stack deploy --compose-file yourFile.yml YOURSTACKNAME
Now all your containers start on the subnet you defined as well as using the gateway you specified.
Configuration of a network within compose v3 is:
networks:
my_network:
driver: overlay
ipam:
driver: default
config:
-
subnet: 172.28.0.0/16
You can then assign your containers to this network and specify the IP
services
my_service:
networks:
my_network:
ipv4_address: 172.28.0.100
For already defined networks, use:
networks:
default:
external:
name: my-pre-existing-network
I've following coder-compose configuration:
version: '2'
services:
nginx:
build: ./nginx
links:
- tomcat1:tomcat1
- tomcat2:tomcat2
- tomcat3:tomcat3
ports:
- "80:80"
tomcat1:
build: ./tomcat
ports:
- "8080"
tomcat2:
build: ./tomcat
ports:
- "8080"
tomcat3:
build: ./tomcat
ports:
- "8080"
So, the question is, how to get access to the host network from the linked container(s):tomcat1, tomcat2, tomcat3. Here is the diagram:
Update
Seems, my diagram doesn't help much. Nginx is a load balancer, Tomcat 1-3 are application nodes. Deployed web. app needs to get access to internet resource.
Internet access is by default active on all containers (in bridge mode). All you need to check is if the http(s)_proxy variables are set if you are behind a proxy.
If your question if how to access docker host from a container (and not the reverse: access a container from the local docker host), then you would need to inspect the routing table of a container: see "From inside of a Docker container, how do I connect to the localhost of the machine?"
export DOCKER_HOST_IP=$(route -n | awk '/UG[ \t]/{print $2}')
There is a recent (June 2016) effort to add a adding a dockerhost as an entry in /etc/hosts of all running containers: issue 23177.
Update March 2020: this issue has been closed, and redirect to PR 40007: "Support host.docker.internal in dockerd on Linux"
This PR allows containers to connect to Linux hosts by appending a special string "host-gateway" to --add-host e.g. "--add-host=host.docker.internal:host-gateway" which adds host.docker.internal DNS entry in /etc/hosts and maps it to host-gateway-ip
This PR also add a daemon flag call host-gateway-ip which defaults to
the default bridge IP
Docker Desktop will need to set this field to the Host Proxy IP so DNS requests for host.docker.internal can be routed to VPNkit
This will be in Docker for Linux (and Docker Desktop, which runs the Linux daemon, although inside a lightweight VM).
Difference between this and the current implementation on Docker Desktop is that;
the current Docker Desktop implementation is in a part of the code-base that's proprietary (i.e., part of how Docker Desktop is configured internally)
this code could be used by the Docker Desktop team in future as well (to be discussed)
this PR does not set up the "magic" host.docker.internal automatically on every container, but it can be used to run a container that needs this host by adding docker run --add-host host.docker.internal:host-gateway
(to be discussed); setting that "magic" domain automatically on containers that are started could be implemented by adding an option for this in the ~/.docker/config.json CLI configuration file.