I have a Jaeger running in a docker container in my local machine.
I've created a sample app which sends trace data to Jaeger. When running from the IDE, the data is sent perfectly.
I've containerized my app, and now I'm deploying it as a container, but the communication only works when I use --link jaeger to link both containers (expected).
My question is:
Is there a way of adding the --link parameter within my Dockerfile, so then I don't need to specify it when running the docker run command?
There is no possibility of doing it in the Dockerfile if you want to keep two separate image. How should you know in advance the name/id of the container you're going to link ?
Below are two solutions :
Use Docker compose. This way, Docker will automatically link all the containers together
Create a bridge network and add all the container you want to link inside. This way, you'll have name resolution and you'll be able to contact each container using its name
I recommend you using netwoking, by creating:
docker network create [OPTIONS] NETWORK
and then run with --network="network"
using docker-compose with network and link to each other
example:
version: '3'
services:
jaeger:
network:
-network1
other_container:
network:
-network1
networks:
network1:
external: true
Related
Is there any way to make a docker container that is accessing to all docker networks at the same time ? The idea is that I have 2 docker networks.
Let's say that they are called demo1 and demo2.
I have another docker container (called Front) that should reach demo1 and demo2 at the same time.
I can do that by declaring external networks in my docker-compose file.
However, I want to be able to declare demo3 and attach the Front container to it "dynamically", without modifying the compose file of the container and if it's possible, without restarting it.
So, I am trying to find an architecture that makes my container Front connect to any added docker network dynamically.
I can create a script in a crontab, but the idea is to do it properly.
The need is to get a common container, which can reach any other container.
In a docker compose syntaxe, I image something like this:
networks:
all:
name: '*'
external: true
Is it possible ? How ?
Regards
I guess what you need is Connect a running container to a network:
Examples
Connect a running container to a network
$ docker network connect multi-host-network container1
Just find the new network name and connect your Front container to this network out of composefile.
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 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.
I tried to setup an nginx-proxy container to access my other containers via subdomains on port 80 instead of special ports. As you can guess, I could not get it to work.
I'm kind of new to docker itself and found that it's more comfortable for me to write docker-compose.yml files so I don't have to constantly write long docker run ... commands. I thought there's no difference in how you start the containers, either with docker or docker-compose. However, one difference I noticed is that starting the container with docker does not create any new networks, but with docker-compose there will be a xxx_default network afterwards.
I read that containers on different networks cannot access each other and maybe that might be the reason why the nginx-proxy is not forwarding the requests to the other containers. However, I was unable to find a way to configure my docker-compose.yml file to not create any new networks, but instead join the default bridge network like docker run does.
I tried the following, but it resulted in an error saying that I cannot join system networks like this:
networks:
default:
external:
name: bridge
I also tried network_mode: bridge, but that didn't seem to make any difference.
How do I have to write the docker-compose.yml file to not create a new network, or is that not possible at all?
Bonus question: Are there any other differences between docker and docker-compose that I should know of?
Adding network_mode: bridge to each service in your docker-compose.yml will stop compose from creating a network.
If any service is not configured with this bridge (or host), a network will be created.
Tested and confirmed with:
version: "2.1"
services:
app:
image: ubuntu:latest
network_mode: bridge
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...