I want a shell inside a Docker Service / Swarm network. Specifically, I want to be able to connect to a database that's inside the network.
From the manager node, I tried:
# docker network ls
NETWORK ID NAME DRIVER SCOPE
481c20b4039a bridge bridge local
2fhe9rtim9mz my-network overlay swarm
Then
docker run -it --network my-network alpine sh
But I get the error:
docker: Error response from daemon: swarm-scoped network (event-data-core-prod) is not compatible with docker create or docker run. This network can only be used by a docker service.
Is it possible to somehow start an interactive session that can connect to a network service?
Since Docker Engine v1.13 (like already mentioned by johnharris85) it is possible for non-service container to attach to a swarm-mode overlay networks using the --attachable commandline parameter when creating the network:
docker network create --driver overlay --attachable my-attachable-overlay-network
Regarding your followup question:
Is there a way to change this for an extant network?
Yes and no, like I already described in another question you can make use of the docker service update feature:
To update an already running docker service:
Create an attachable overlay network:
docker network create --driver overlay --attachable my-attachable-overlay-network
Remove the network stack with a disabled "attachable" overlay network (in this example called: my-non-attachable-overlay-network):
docker service update --network-rm my-non-attachable-overlay-network myservice
Add the network stack with an enabled "attachable" overlay network:
docker service update --network-add my-attachable-overlay-network myservice
Related
CentOS 7
Docker 20.10
I want to delete all networks.
docker container ls
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
As you can see no containers. I was removed it before.
I try this:
docker network ls
NETWORK ID NAME DRIVER SCOPE
1b6758d38df3 bridge bridge local
89dea066d590 host host local
8e235018309e none null local
And this:
docker network rm 1b6758d38df3
Error response from daemon: bridge is a pre-defined network and cannot be removed
P.S the folder /var/lib/docker is empty
Those are the system networks included in every Docker installation, they are not like user-defined networks and cannot be removed.
From the docs for thedocker network prune command:
Note that system networks such as bridge, host, and none will never be pruned
From the Network containers tutorial page:
Every installation of the Docker Engine automatically includes three default networks.
[...]
The network named bridge is a special network. Unless you tell it otherwise, Docker always launches your containers in this network.
This would mean that removing those networks would break some of Docker's networking features.
For what purpose do you want to remove/delete default network provided by Docker... Please share your use case so some one from community can guide you accordingly...
Bridge, Host & None are default & pre defined network... These networks are created during installation of docker....
Bridge - All containers without --network options get created within
bridge network only
To verify this you can run following commands -
docker run -it --rm --name=default-bridge-container1 busybox
As above command does not have --network option then it will be create container default-bridge-container1 under bridge network. To verify this, Run
docker network inspect bridge
Under containers section of inspect command, you will see container name default-bridge-container1 with IP assigned to it from bridge subnet.
Host - this option tells to use underlying host network
None - Container with --network=none means container is running in
isolation & it has no access to inward or outward network.
Below is the command used to create overlay network driver for swarm cluster instead of using bridge network driver
$ docker network create -d overlay xyz
$ docker network ls
NETWORK ID NAME DRIVER SCOPE
9c431bc9fec7 bridge bridge local
88a4c6a29fa4 docker_gwbridge bridge local
10a4bc649237 host host local
o79qllmq86xw ingress overlay swarm
417aca5efd6b none null local
nsteeoxfu9b1 xyz overlay swarm
$
$ docker service create --name service_name --network xyz -p 80:80 --repicas 12 <image>
What exactly is the purpose of service command using option --network xyz? is this the network namespace driver?
docker service create --network is described as Network attachments (ref. docker service create --help), it is to attach a service to an existing docker network as documented here. You can attach a service to multiple docker networks.
I'm trying to update the network of a running docker container.
Note: I didn't attach any network while running the container.
[root#stagingrbt ~]# docker network connect host cdf8d6e3013d
Error response from daemon: container sharing network namespace with another container or host cannot be connected to any other network
[root#stagingrbt ~]# docker network connect docker_gwbridge cdf8d6e3013d
error during connect: Post http://%2Fvar%2Frun%2Fdocker.sock/v1.39/networks/docker_gwbridge/connect: EOF
[root#stagingrbt ~]# docker network create -d host my-host-network
Error response from daemon: only one instance of "host" network is allowed
[root#stagingrbt ~]# docker network ls
NETWORK ID NAME DRIVER SCOPE
495080cf93e3 bridge bridge local
cf0408d6f13f docker_gwbridge bridge local
2c5461835eaf host host local
87e9cohcbogh ingress overlay swarm
84dbd78101e3 none null local
774882ac9b09 sudhirnetwork bridge local
When you start a container, such as:
docker run -d --name alpine1 alpine
It is by default connected to the bridge network, check it with:
docker container inspect alpine1
If you try to connect it to host network with:
docker network connect host alpine1
you obtain an error:
Error response from daemon: container cannot be disconnected from host network or connected to host network
you have to delete the container and run it again on the host network:
docker stop alpine1
docker rm alpine1
docker run -d --network host --name alpine1 alpine
This limitation is not present on bridge networks. You can start a container:
docker run -d --name alpine2 alpine
disconnect it from the bridge network and reconnect it to another bridge network.
docker network disconnect bridge alpine2
docker network create --driver bridge alpine-net
docker network connect alpine-net alpine2
Note also that according to the documentation:
The host networking driver only works on Linux hosts, and is not supported on Docker Desktop for Mac, Docker Desktop for Windows, or Docker EE for Windows Server.
If you want to circumvent the command line and change the network of your docker container via portainer, you can do so. I'm not sure exactly which is the best way of doing this, but the steps below worked for me (changing a container that was running on the bridge network by default into the host network):
In the Container list, click on the container name (emby, in my case)
Stop the container
Click on Duplicate/Edit
Scroll down to Advanced container settings and select the Network tab
Change the Network to host (or whatever you want to set it to)
Click on Deploy the container right above.
Confirm that you want to replace the old container (or deploy it under a new name if you want to be on the save side and keep the old one).
Done!
Run or connect a container to a specific network: Note first of all, the network must exist already on the host. Either specify the network at container creation/startup time (docker create or docker run) with the --net option; or attach an existing container by using the docker network connect command. For example:
docker network connect my-network my-container
I am not sure if we can change the container network while running, however, assuming that the new docker network already exists, you can run the following commands to update your container network.
Executed on Version: 20.10.21 Community Edition
# docker stop <container-name>
# docker network disconnect <old-network-id> <container-name>
# docker network connect <new-network-id> <container-name>
# docker start <container-name>
Note: you won't be able to switch to host network from other network
I encounter a problem when using the 'docker run' on the worker node,
the scenario is as follows:
I have following three VMs in my environment,
and they are already in the Swarn mode.
VM.1 -> Master node in the Swarm
VM.2 -> Worker node in the Swarm
VM.3 -> Worker node in the Swarm
and I've also created the overlay network in this environment via:
docker network create --attachable --driver overlay --subnet 10.10.0.0/16 --gateway 10.10.0.1 test-net
and the overlay network is created successfully
# docker network ls
NETWORK ID NAME DRIVER SCOPE
fc1b70304011 bridge bridge local
f9ca924c1a4d docker_gwbridge bridge local
ea8fc696d6f1 host host local
r311gaq7iobo ingress overlay swarm
bd08afac574d none null local
wb7vfpxzdkyt test-net overlay swarm
but, once I use 'docker run' to run a container and let it join the "test-net" from the worker node(VM.2 and VM.3), then I will encounter the following problem:
# docker run -itd --name=test --net=test-net kafka:latest
c0324e6c3a8720b291cfc3aa7980846348f7a4450381036927924c52d343f622
docker: Error response from daemon: error creating external
connectivity network:
cannot create network
246bb018a15a6641a9cb26afec30c62eb4714816cfc0a307786c8a209a2418e6
(docker_gwbridge):
conflicts with network
0093ca50dcbcf729aeeae537f424727b674843312ef63ea647db48c7b0077e45
(docker_gwbridge): networks have same bridge name.
but, it will be worked if I use the same 'docker run' command on the Master node, I've google this problem for serval times but still not understand what is happening on the worker node...
Thanks for your reading and help!
During investigating,
this issue is not 100% reproduced on the other machine/distribution.
some machines can be worked by docker run -itd --name=test --net=test-net kafka:latest
but, if the way above is not worked in specific machine,
then you can try to run the container without --net first,
then use docker network connect --ip <ipaddress> <network> <container> for
appending the specific network at your container.
I am trying to deploy my app with Compose and Swarm. Currently I don't want to upgrade my docker-compose.yaml from v2 to v3. So I am only able to do that with standalone(legacy) swarm rather that docker swarm mode based on Stoneman's answer and official Swarm documents.
Following the official instruction, I successfully set up a swarm cluster. I ran docker -H :4000 info on the swarm manager node to check the swarm cluster status, as shown below. There are two other worker nodes in this cluster. Next, I want to create an overlay network with this cluster and refer this network in the docker-compose.yaml. But when I ran docker -H :4000 network create -d overlay test on the swarm manager node to create the netwrok, it reported error: Error response from daemon: Error response from daemon: This node is not a swarm manager. Use "docker swarm init" or "docker swarm join" to connect this node to swarm and try again.
So, how can I create a network with a swarm cluster( without docker-machine and virtual box)? Currently, the swarm manager and worker nodes are running as docker containers.
Did you setup overlay networking with it's own etcd backend first? https://docs.docker.com/network/overlay-standalone.swarm/
Swarm "classic" is deprecated and replaced by docker swarm mode. Everything is harder in classic, including setting up overlay. I wouldn't recommend using it for anything new unless you had a hard requirement.
In swarm mode you run all commands at the swarm manager host. Same with creating networks, secrets, etc.
You can find out the docker manager machine by:
$docker node ls
Manager host is marked with MANAGER STATUS:Leader.
After creating the network on the manager all nodes on that swarm should see the network.
"I ran docker -H :4000 network create -d overlay test"
Better to declare the network inside the stack yml file, for faster and easier deployment. you can create network and expose your ports at the yml file, no need to create them manually every time you run the stack.
Add the following block under the docker service:
services:
...
#Network
networks:
- network-name-here
...
#Exposed ports:
ports:
- target: 4000
published: 4000
At the end of the yml file add the following block to declare the network, so its created every time you run $docker stack deploy:
networks:
network-name-here:
driver: overlay