Let say I have running orchestration with docker-compose with docker-compose.yml looking like this:
version: '2.2'
services:
service1:
# ...
networks:
- compose_network
service2:
# ...
networks:
- compose_network
networks:
compose_network:
I aim to run and connect temporarily one container to compose_network_1. I tried using
$ docker run --net=compose_network <image for the job>
but I could not connect. I am also aware that docker-compose names the networks as [projectname]_default, so I also tried that variant, but with same result.
Is there a way I can accomplish that?
I'm not sure if the --net option ever existed but it's now --network.
From docker run --help:
--network string Connect a container to a network (default "default")
As #maxm notes you can find the network name, with the DIR prefix of the compose project directory, then simply run it as you were trying:
$ docker run --network=DIR_compose_network <image for the job>
I wanted to connect on run as my container is transient (running tests) so I can't use a second docker network command in time before it quits.
e.g. for my docker composition in a "dev" folder with no network name specified so uses the docker-compose "default" name, therefore I get the name dev_default.
docker network ls
NETWORK ID NAME DRIVER SCOPE
2c660d9ed0ba bridge bridge local
b81db348e773 dev_default bridge local
ecb0eb6e93a5 host host local
docker run -it --network dev_default myimage
This connects the new docker container to the existing docker-compose network.
The network name is going to be something like name-of-directory_compose_network. Find the name with docker network ls
I had success with:
docker-compose up # within directory ./demo
docker run -itd -p "8000:8000" --hostname=hello "crccheck/hello-world"
# outputs: 1e502f65070c9e2da7615c5175d5fc00c49ebdcb18962ea83a0b24ee0440da2b
docker network connect --alias hello demo_compose_network 1e502f65070c
I could then curl hello:8000 from inside my docker compose containers. Should be the exact same functionality as your commands, just with an added alias.
Related
Is there any proper way of restarting an entire docker compose stack from within one of its containers?
One workaround involves mounting the docker socket:
volumes:
- /var/run/docker.sock:/var/run/docker.sock
and then use the Docker Engine SDKs (https://docs.docker.com/engine/api/sdk/examples/).
However, this solution only allows restarting the containers itselves. There seems to be no way to send compose commands, like docker compose restart, docker compose up, etc.
The only solution I've found to send docker compose commands is to open a terminal on the host from the container using ssh, like this: access host's ssh tunnel from docker container
This is partly related to How to run shell script on host from docker container? , but I'm actually looking for a more specific solution to only send docker compose commands.
I tried with this simple docker-compose.yml file
version: '3'
services:
nginx:
image: nginx
ports:
- 3000:80
Then I started a docker container using
docker run -it --rm -v /var/run/docker.sock:/var/run/docker.sock -v $(pwd):/work docker
Then, inside the container, I did
cd /work
docker-compose up -d
and it started the container up on the host.
Please note that you have an error in your socket mapping. It needs to be
- /var/run/docker.sock:/var/run/docker.sock
(you have a period instead of a slash at one point)
As mentioned by #BMitch in the comments, compose project name was the reason why I wasn't able to run docker compose commands inside the running container.
By default the compose project name is set to the directory name, so if the docker-compose.yml is run from a host directory named folder1, then the commands inside the container should be run as:
docker-compose -p folder1 ...
So now, for example, restarting the stack works:
docker-compose -p folder1 restart
Just as a reference, a fixed project name for your compose can be set using name: ... as a top-level attribute of the .yml file, but requires docker compose v2.3.3 : Set $PROJECT_NAME in docker-compose file
Running 2 containers where mycontainer2 must use the same network stack of mycontainer1. As if the two containers were running in the same machine. Here how I try to do by using docker run with --network container:xxx
$ docker run -it --rm --name mycontainer1 -p 6666:7777 myregistry/my-container1:latest
$ docker run -it --rm --network container:mycontainer1 --name mycontainer2 myregistry/my-container2:latest
I tried to replicate this behavior using docker-compose instead. But the networks: definition of docker-compose.yaml doesn't indicate something equivalent to the --network container:xxx option of docker run. Is it possible in docker-compose to configure two containers to use the same network stack?
This is a network_mode: setting.
version: '3.8'
services:
mycontainer1:
image: myregistry/my-container1:latest
ports: ['6666:7777']
mycontainer2:
image: myregistry/my-container2:latest
network_mode: service:mycontainer1 # <---
Since Compose will generally pick its own container names, this service:name form uses the container matching the named Compose service. (If you override container_name: then you can also use container:mycontainer1 the same way you did with docker run.)
Creating an external network and use it inside docker-compose YAML manifest might help. Here is how you do it.
version: '3.7'
networks:
default:
external:
name: an-external-network
services:
my-container1:
...
my-container2:
...
Note: use docker network create command to create an-external-network before running docker-compose up command.
When deploying a stack of this compose file using:
docker stack deploy -c docker-compose.yml myapp
service-name:
image: service-image
namelike-property: my-custom-service-name // here I would like to know the property
The generated service name will be myapp_service-name
I would want it to be named and referenced by my-custom-service-name
I think you can use "container_name" to specify the name of container in your yml file. Some like:
service-name:
image: service-image
container_name: my-custom-service-name
For communication between services you can use the serviceName as defined in the compose file (in your case your service name is service-name) if both services communicating are in the same network.
When you do docker service ls the stackname will be shown before every service. That's done because its possible to have two services with the same name which are not in a shared network. You can't change that and it wouldn't make sense to do that because that name is not important and is actually just an ID. You can however change the name of your stack to get ${StackNameILike}:${ServiceNameILike}
I do not think it is supported (yet).
docker service does support this
#!/bin/bash
SERVICE_NAME=myservice
docker service create \
--name $SERVICE_NAME \
--hostname $SERVICE_NAME \
--network myoverlayattachableswarmscopednetwork \
# IMAGE GOES HERE
I was able to log into a service and ping another one on the same network by the name I provided.
For example
docker exec -it $(docker ps -q -f name=myotherservice) bash
ping myservice
note that container_name is not supported in the docker-compose.yml file when using docker stack up|deploy
If you need this for referencing from other services by service registry, you can use the following definition.
service-name:
image: ....
network:
my-network:
aliases:
- ref-name
I am trying to run docker networking with compose in docker 1.9. I know this is still experimental in 1.9, but I'd like to know if my use case could work.
Basically and to simplify, I have two servers, each one being in a container. Let's call them S1 and S2. S1 is exposed globally and must be accessible from S2. I want to run S2 through docker-compose with the --x-networking flag (the reason why I want this is that S2 is actually a bit more complexe than what is assumed here, having several containers, and I want them to run in a single subnetwork). S1 can run with or without compose.
What I understand from docker networks is that any container can reach other from the same network, or can reach anything that is "globally" exposed through host port mapping, right?
So my scenario is:
I start manually S1 with port mapping such as "-p 7210:7202" (7202 is exposed in dockerfile)
S2 is created from a simple compose file and gone up with flag --x-networking
For my test case I just created a very minimalistic compose file, such as:
S2:
build: .
ports:
- "8080:80"
Results:
S1 is NOT visible from S2 under "localhost" (this is quite expected)
S1 is NOT visible from S2 under "172.17.0.1" (= interface docker0)
I would have expected to be able to reach it under 172.17.0.1, since S1 uses docker0 as I understand.
Moreover, if I start S2 without compose but manually with "docker run", then I can access S1 using 172.17.0.1
So why doesn't it work with compose? Is it a limitation due to networking features being still experimental?
Note:
This is old content. The --x-networking has been removed in docker-compose
1.6. Additionally Docker compose has a new file format.
The documentation states that the networking feature is experimental in Docker compose.
Note: Compose’s networking support is experimental, and must be
explicitly enabled with the docker-compose --x-networking flag.
It's Docker 1.9 that actually implements the new feature:
https://docs.docker.com/engine/userguide/networking/dockernetworks/
Perhaps an example would help.
Example
└── demo
└── docker-compose.yml
I'm using docker 1.9.0 and docker-compose 1.5.0
docker-compose.yml
Declare two containers callled "web1" and "web2". Doesn't matter what image in this case I'm running tomcat.
web1:
image: tomcat:8.0
ports:
- 8080
web2:
image: tomcat:8.0
ports:
- 8080
Create the containers
Start this using docker compose
$ cd demo
$ docker-compose --x-networking up -d
Creating network "demo" with driver "None"
Creating demo_web2_1
Creating demo_web1_1
Note how a network called "demo" is created when you specified the new --x-networking parameter.
Demonstrate how discovery works
Each container is run on the "demo" network that was created and each container is placed as an entry in the other hosts file.
$ docker-compose ps
Name Command State Ports
---------------------------------------------------------------
demo_web1_1 catalina.sh run Up 0.0.0.0:32773->8080/tcp
demo_web2_1 catalina.sh run Up 0.0.0.0:32772->8080/tcp
$ docker exec -it demo_web1_1 cat /etc/hosts
..
172.18.0.2 demo_web2_1
$ docker exec -it demo_web2_1 cat /etc/hosts
..
172.18.0.3 demo_web1_1
Run an additional container outside of compose
Start another container, and specify you want it to be attached to the "demo" network:
$ docker run --net demo --name helloworld -d tomcat:8.0
And see how the hosts files in the other containers is updated automatically
$ docker exec -it demo_web1_1 cat /etc/hosts
..
172.18.0.2 demo_web2_1
172.18.0.4 helloworld
$ docker exec -it demo_web2_1 cat /etc/hosts
172.18.0.3 demo_web1_1
172.18.0.4 helloworld
$ docker exec -it helloworld cat /etc/hosts
172.18.0.2 demo_web2_1
172.18.0.3 demo_web1_1
Suppose I have a docker compose file with two containers. Both reference each other in their /etc/hosts file. Container A has a reference for container B and vice versa. And all of this happens automatically. Now I want to add one or more hostnames to B in A's hosts file. How can I go about doing this? Is there a special way I can achieve this in Docker Compose?
Example:
172.0.10.166 service-b my-custom-hostname
Yes. In your compose file, you can specify network aliases.
services:
db:
networks:
default:
aliases:
- database
- postgres
In this example, the db service could be reached by other containers on the default network using db, database, or postgres.
You can also add aliases to running containers using the docker network connect command with the --alias= option.
Docker compose has an extra_hosts feature that allows additional entries to be added to the container's host file.
Example
docker-compose.yml
web1:
image: tomcat:8.0
ports:
- 8081:8080
extra_hosts:
- "somehost:162.242.195.82"
- "otherhost:50.31.209.229"
web2:
image: tomcat:8.0
ports:
- 8082:8080
web3:
image: tomcat:8.0
ports:
- 8083:8080
Demonstrate host file entries
Run docker compose with the new docker 1.9 networking feature:
$ docker-compose --x-networking up -d
Starting tmp_web1_1
Starting tmp_web2_1
Starting tmp_web3_1
and look at the hosts file in the first container. Shows the other containers, plus the additional custom entries:
$ docker exec tmp_web1_1 cat /etc/hosts
..
172.18.0.4 web1
172.18.0.2 tmp_web2_1
172.18.0.3 tmp_web3_1
50.31.209.229 otherhost
162.242.195.82 somehost
If I understand your question correctly, you can pass a host name referenced in your host's /etc/hosts file via --add-host flag :
$ docker run ... --add-host="droid"
Your host's /etc/hosts would need the following entry:
xx.xx.xx.xx droid
Of course, xx.xx.xx.xx will need to be reachable from inside the container you just started using the 'docker run' command. You can have one or more --add-host="xyz".
More details about --add-host here:
http://docs.docker.com/v1.8/reference/commandline/run/