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.
Related
I'd like to be able to connect to localstack using the host rather than the service name. I have added the localstack image to my docker-compose file and set network_mode: "host". I can connect to http://localhost:8080 from my other containers. But, I can not connect to: http://localhost:8080 from my host machine. How can I connect to a container using localhost rather than the service name? Not sure if I have misunderstood what network_mode: "host" does.
version: "3"
services:
localstack:
image: localstack/localstack:latest
network_mode: "host"
ports:
- "4567-4584:4567-4584"
- "${PORT_WEB_UI-8080}:${PORT_WEB_UI-8080}"
environment:
- AWS_REGION=us-east-1
- SERVICES=sqs
Problem is I'm using CircleCI to run some component tests, but it seems that in CircleCI you can only reference other services on localhost and not via the service name. This means there are some difference between my local environment and test environment configs. I tried running docker-compose in CircleCI but it seems to freak out locally when doing that. So I wanted to see if I can reference localhost between services in docker-compose.
This happens because Docker for Mac runs inside a virtual machine using the xhyve hypervisor not natively on macOS.
When you run the container with net=host you are actually using the network of the VM and not the one from your local machine.
This is a known limitation of Docker for mac given the nature of how it works.
The only way to access a container is by using port mapping, so if you remove the network_mode:"host" from your docker-compose file it should work as you are already mapping ports.
I am trying to communicate from one Docker container running on my Win10 laptop with another container also running locally.
I start up the target container, and I see the following network:
docker network ls
NETWORK ID NAME DRIVER SCOPE
...
f85b7c89dc30 w3virtualservicew3id_w3-virtual-service-w3id bridge
I then start up my calling container with docker-compose up. I can then successfully connect my other container to the network via the command line:
docker network connect w3virtualservicew3id_w3-virtual-service-w3id w3vacationatibmservice_rest_1
However, I can't connect to that same network by adding it to the network section of my docker-compose.yml file for the calling container. I was under the impression that they both basically did the same thing:
networks:
- w3_vacation-at-ibm_service
- w3virtualservicew3id_w3-virtual-service-w3id
The error message tells me it can't find the network, which is not true, since I can connect via the command line, so I know it's really there and running:
ERROR: Service "rest" uses an undefined network "w3virtualservicew3id_w3-virtual-service-w3id"
Anyone have any idea what I'm missing?
The network you define under your service is expected to be defined inside the global networks section (same thing for volumes):
version 'X.Y'
services:
calling_container:
networks:
- your_network
networks:
your_network:
external: true
Do you really have to use a separate compose yml for your calling container? If both of your container interacts with each other, you should add them both to one and the same compose yml. In this case, you don't have to specifiy any network, they will automatically be inside the same network.
Currently in the company where I am working on they have a central development server which contains a LAMP environment. Each developer has access to the application as: developer_username.domain.com. The application we're working on uses licenses and the licenses are generated under each domain and are tied to the domain only meaning I can't use license from other developer.
The following example will give you an idea:
developer_1.domain.com ==> license1
developer_2.domain.com ==> license2
developer_n.domain.com ==> licenseN
I am trying to dockerize this enviroment at least having PHP and Apache in a container and I was able to create everything I need and it works. Take a look to this docker-compose.yml:
version: '2'
services:
php-apache:
env_file:
- dev_variables.env
image: reypm/php55-dev
build:
context: .
args:
- PUID=1000
- PGID=1000
ports:
- "80:80"
- "9001:9001"
extra_hosts:
- "dockerhost:xxx.xxx.xxx.xxx"
volumes:
- ~/var/www:/var/www
That will build what I need but the problem comes when I try to access the server because I am using http://localhost and then the license won't work and I won't be able to use the application.
The idea is to access as developer_username.domain.com, so my question is: is this a work that should be done on the Dockerfile or the Docker Compose I mean at image/container level let's say by setting up a ENV var perhaps or is this a job for /etc/hosts on the host running the Docker?
tl;dr
No! Docker doesn't do that for you.
Long answer:
What you want to do is to have a custom hostname on the machine hosting docker mapped to a container in Docker compose network. right?
Let's take a step back and see how networking in docker works:
By default Compose sets up a single network for your app. Each container for a service joins the default network and is both reachable by other containers on that network, and discoverable by them at a hostname identical to the container name.
This network is not equal to your host network and without explicit ports exporting (for a specific container) you wouldn't have access to this network. All exposing does, is that:
The exposed port is accessible on the host and the ports are available to any client that can reach the host.
From now on you can put a reverse proxy (like nginx) or you can edit /etc/hosts to define how clients can access the host (i.e. Docker host, the machine running Docker compose).
The hostname is defined when you start the container, overwriting anything you attempt to put inside the image. At a high level, I'd recommend doing this with a mix of custom docker-compose.yml and a volume per developer, but each running an identical image. The docker-compose.yml can include the hostname and domain setting. Then everything else that needs to be hostname specific on the filesystem, and the license itself, should point to files on the volume. Lastly, include an entrypoint that does the right thing if a new hostname is started with a default or empty volume, populating it with the new hostname data and prompting for the license.
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.
I assume that there is a way to link via one or a combination of the following: links, external_links and networking.
Any ideas? I have come up empty handed so far.
Here is an example snippet of a Docker-compose which is started from within a separate Ubuntu docker
version: '2'
services:
web:
build: .
depends_on:
- redis
redis:
image: redis
I want to be able to connect to the redis port from the Docker that launched the docker-compose.
I do not want to bind the ports on the host as it means I won't be able to start multiple docker-compose from the same model.
-- context --
I am attempting to run a docker-compose from within a Jenkins maven build Docker so that I can run tests. But I cannot for the life of me get the original Docker to access exposed ports on the docker-compose
Reference the machines by hostname, v2 automatically connects the nodes by hostname on a private network by default. You'll be able to ping "web" and "redis" from within each container. If you want to access the machines from your host, include a "ports" definition for each service in your yml.
The v1 links were removed from the v2 compose syntax since they are now implicit. From the docker compose file documentation
links with environment variables: As documented in the environment variables reference, environment variables created by links have been
deprecated for some time. In the new Docker network system, they have
been removed. You should either connect directly to the appropriate
hostname or set the relevant environment variable yourself...