I've got a swarm set up with a two nodes, one manager and one worker. I'd like to have a port published in the swarm so I can access my applications and I wonder how I achieve this.
version: '2'
services:
server:
build: .
image: my-hub.company.com/application/server:latest
ports:
- "80:80"
This exposes port 80 when I run docker-compose up and it works just fine, however when I run a bundled deploy
docker deploy my-service
This won't publish the port, so it just says 80/tcp in docker ps, instead of pointing on a port. Maybe this is because I need to attach a load balancer or run some fancy command or maybe add another layer of config to actually expose this port in a multi-host swarm.
Can someone help me understand what I need to configure/do to make this expose a port.
My best case scenario would be that port 80 is exposed, and if I access it from different hostnames it will send me to different applications.
Update:
It seems to work if I run the following commands after deploying the application
docker service update -p 80:80 my-service_server
docker kill <my-service_server id>
I found this repository for running a HA proxy, it seems great and is supported by docker themselves, however I cannot seem to apply this separate to my services using the new swarm mode.
https://github.com/docker/dockercloud-haproxy
There's a nice description in the bottom describing how the network should look:
Internet -> HAProxy -> Service_A -> Container A
However I cannot find a way to link services through the docker service create command, optimally now looks like a way to set up a network, and when I apply this network on a service it will pick it up in the HAProxy.
-- Marcus
As far as I understood for the moment you just can publish ports updating the service later the creation, like this:
docker service update my-service --publish-add 80:80
Swarm mode publishes ports in a different way. It won't show up in docker ps because it's not publishing the port on the host, it publishes the port to all nodes so that takes it can load balancing between service replicas.
You should see the port from docker service inspect my-service.
Any other service should be able to connect to my-service:80
docker service ls will display the port mappings.
Related
I have a NAS where I am running various web apps in docker containers through docker-compose. I want some of these web apps to be accessible through the internet, not only when I am connected to my home network.
The problem I'm currently facing is that while cloudflare is able to expose the default web apps (default NAS management 192.168.1.135:80 can be mapped to subdomain.domain.com, for instance), it is unable to expose any docker container I try to run (192.168.1.135:4444 cannot be mapped to subdomain2.domain.com), and I receive a 502 bad gateway error with every app I have tried so far.
The configuration shouldn't be the issue, and it's definitely not the NoTLSVerify flag because the apps run on HTTP and I have configured it that way, so I am out of options to know what is going on and how to solve it.
Looks like the apps you're running on your NAS are proxied through the docker runtime. Consequently, the IP:port you need to add to the cloudflare tunnel config is the one that is reachable from the Host (not the IP of the host itself).
If the host is 192.168.1.135, you need to know which the the IP (internal to the docker network) of the app that you want to access from the outside, typically in the 172.0.0.1/24 range.
Example: If the containers running the apps you want to access are running on 172.0.0.2:4444 for app1 and 172.0.0.3:5555 for app2, the cloudflare config would look like this:
tunnel: the_ID_of_the_tunnel
credentials-file: /root/.cloudflared/the_ID_of_the_tunnel.json
ingress:
- hostname: yourapp1.example.com
service: http://172.0.0.2:4444
- hostname: ypurapp2.example.com
service: http://172.0.0.3:5555
- service: http_status:404
See more details and a video here: How to redirect subdomain to port (docker)
Turns out the problem is due to how docker works with networks, not with how Cloudflare accesses them. I first had to create a network that connected both containers, since adding cloudflare to my docker-compose file didn't work for some reason.
Create a docker network docker network create tunnel
Run docker without specifying the network docker run -d --name cloudflare cloudflare/cloudflared:latest tunnel --no-autoupdate run --token
Add the docker to the network docker network connect tunnel cloudflare
Run the container (note the container should have, as you specified, the network name identical to the one you created earlier, but cloudflare should not be in your docker-compose file) docker-compose up
In the cloudflare tunnel config, you will have to specify the docker internal address of your container (as #lu4t suggested). You can identify the address with docker inspect -f '{{range.NetworkSettings.Networks}}{{.IPAddress}}{{end}}' container
To start, I am more familiar running Docker through Portainer than I am with doing it through the console.
What I'm Doing:
Currently, I'm running Mopidy through a container, which is being accessed by other machines through the default Mopidy port. In another container, I am running a Slack bot using the Limbo repo as a base. Both of them are running on Alpine Linux.
What I Need:
What I want to do is for my Slack bot to be able to call MPC commands, such as muting the volume, etc. This is where I am stuck. What is the best way for this to work
What I've tried:
I could ssh into the other container to send a command, but it doesn't make sense to do this since they're both running on the same server machine.
The best way to connect a bunch of containers is to define a service stack using docker-compose.yml file and launch all of them using docker-compose up. This way all the containers will be connected via single user-defined bridge network which will make all their ports accessible to each other without you explicitly publishing them. It will also allow the containers to discover each other by the service name via DNS-resolution.
Example of docker-compose.yml:
version: "3"
services:
service1:
image: image1
ports:
# the following only necessary to access port from host machine
- "host_port:container_port"
service2:
image: image2
In the above example any application in the service2 container can reach some port on service1 just by using service2:port address.
I am planning to use rancher for managing my containers. On my dev box, we plan to bring up several containers each serving a REST api.
I am able to automate the process of building up my containers using jenkins and want to run the container using rancher to take advantage of random host port mapping. I am able to do this using rancher UI but unable to find the way to automate it using cli.
ex:
Jennkins builds Container_A exposes 8080 -> Jenkins also executes rancher cli to run the container mapping 8080 to a random port of host. And the same for Container_B exposing 8080.
Hope my question makes sense.
Thanks
Vijay
You should just be able to do this in the service definition in the Docker compose yaml file:
...
publish:
8080
...
If you generate something in the UI and look at the configuration of the stack, you'll see the corresponding compose yml.
Alternatively, you can use:
rancher run --publish 8080 nginx
then get the randomly assigned port:
rancher inspect <stackname>/<service_name> | jq .publicEndpoints[].port
Questions like seem to be asked but I really don't get it at all.
I have a window 10 dev machine host with docker for windows installed. Besides others networks it has DockerNAT netwrok with IP 10.0.75.1
I run some containers with docker-compose:
version: '2'
services:
service_a:
build: .
container_name: docker_a
It created some network bla_default, container has IP 172.18.0.4, ofcource I can not connect to 172.18.0.4 from host - it doesn't have any netwrok interface for this.
What should I do to be able to access this container from HOST machine? (by IP) and if possible by some DNS name? What should I add to my docker-compose.yml, how to configure netwroks?
For me it should be something basic, but I really don't understand how all this stuff works and to access to container from host directly.
Allow access to internal docker networks from dev machine:
route /P add 172.0.0.0 MASK 255.0.0.0 10.0.75.2
Then use this https://github.com/aacebedo/dnsdock to enable DNS discovery.
Tips:
> docker run -d -v /var/run/docker.sock:/var/run/docker.sock --name dnsdock --net bridge -p 53:53/udp aacebedo/dnsdock:latest-amd64
> add 127.0.0.1 as DNS server on dev machine
> Use labels described in docs to have pretty dns names for containers
So the answer on the original question:
YES WE CAN!
Oh, this not actual.
MAKE DOCKER GREAT AGAIN!
The easiest option is port mapping: https://docs.docker.com/compose/compose-file/#/ports
just add
ports:
- "8080:80"
to the service definition in compose. If your service listens on port 80, requests to localhost:8080 on your host will be forwarded to the container. (I'm using docker machine, so my docker host is another IP, but I think localhost is how docker for windows appears)
Treating the service as a single process listening on one (or a few) ports has worked best for me, but if you want to start reading about networking options, here are some places to dig in:
https://docs.docker.com/engine/userguide/networking/
Docker's official page on networking - a very high level introduction, with most of the detail on the default bridge behavior.
http://www.linuxjournal.com/content/concerning-containers-connections-docker-networking
More information on network layout within a docker host
http://www.dasblinkenlichten.com/docker-networking-101-host-mode/
Host mode is kind of mysterious, and I'm curious if it works similarly on windows.
Use case: haproxy container running with docker compose. I want to have the container discover which hosts are available in order to recreate haproxy config and reload it.
I know the there will be one or more containers named server1 and server2 available. From inside the haproxy container I can query dns for server1 and receive more than one IP address. Is that the only way to know when a new server1 cointainer becomes available or dies? I know I can use the docker api from python running inside a container that hast the docker host socket mapped to it, but I'm not sure that will work when running on swarm.
The perfect solution would be an api or command that let's me register an event handler that is called when a new container joins the network.
There is a solutions that you can use Registrator (https://github.com/gliderlabs/registrator), Consul and Consul Template.
Consul is a Service Discovery
Consul-Template watches Consul and updates HA Proxy config and reload it.
Registrator listens Docker Engine and update Consul if there is any container is up or down.
Please see the image:
For the full tutorial, you can refer to my blog (https://sonnguyen.ws/microservices-with-docker-swarm-and-consul/) to know how to implement it.