According to the official documentation on Install and Create a Docker Swarm, first step is to create a vm named local which is needed to obtain the token with swarm create.
Once the manager and all nodes have been created and added to the swarm cluster, do I need to keep running the local vm?
Note: this tutorial is for the first version of Swarm (called Swarm legacy). There is a new version called Swarm mode available since Docker 1.12. Putting it out there because there seems to be a lot of confusion between the two.
No you don't have to keep the local VM, this is just to get a unique cluster token with the Docker Hub discovery service.
Now this is a bit overkill just to generate a token. You can bypass this step by:
Running the swarm container directly if you have Docker for Mac or a more generally a local instance of Docker running:
docker run --rm swarm create
Directly query the service discovery URL to generate a token:
curl -X POST "https://discovery.hub.docker.com/v1/clusters"
Related
After looking through docker official swarm explanations, github issues and stackoverflow answers im still at a loss on why i am having the problem that i have.
Issue at hand: docker-compose up starts services not in the swarm even though swarm is active and has 2 nodes.
Im using 1.12.1 docker version.
Looking at swarm tutorial i was able to start and scale my swarm using docker service create without any issues.
running docker-compose up with version 2 docker-compose.yml results in services starting outside of swarm, i can see them through docker ps but not docker service ls
I can see that docker-machine as the tool that solves this problems, but then again it needs virtual box to be installed.
so my questions would be
Can i use docker-compose with docker-swarm (NOT docker-engine) without docker-machine and without experimental build bundle functionality?
If docker service create can start a service on any nodes is it an indication that network configuration of the swarm is correct ?
What is the advantages/disadvantages of docker-machine versus experimental build functionality
1) No. Docker Compose isn't integrated with the new Swarm Mode yet. Issue 3656 in GitHub is tracking that. If you start containers on a swarm with Docker Compose at the moment, it uses docker run to start containers, which is why you see them all on one node.
2) Yes. Actually you can use docker node ls on the manager to confirm all the nodes are up and active, and docker node inspect to check a particular node, you don't need to create a service to validate the swarm.
3) Docker Machine is also behind the 1.12 release, so if you start a swarm with Docker Machine it will be the 'old' type of swarm. The old Docker Swarm product needed a whole lot of extra setup for a key-value store, TLS etc. which Swarm Mode does for free.
1) You can't start services using docker-compose on the new Docker "Swarm Mode". There's a feature to convert a docker-compose file to the new dab format which is understood by the new swarm mode but that's incomplete and experimental at this point. You basically need to use bash scripts to start services at the moment.
2) The nodes in a swarm (swarm mode) interact using their own overlay network. It's the one named ingress when you do docker network ls. You need to setup your own overlay network to run services in. eg:
docker network create -d overlay mynet
docker service create --name serv1 --network mynet nginx
3) I'm not sure what feature you mean by "experimental build'. docker-machine is just a way to create hosts (the nodes). It facilitates the setting up of the docker daemon on each host, the certificates and allows some basic maintenance (renewing the certs, stopping/starting a host if you're the one who created it). It doesn't create services, volumes, networks or manages them. That's the job of the docker api.
I currently have three hosts (docker1, docker2 and docker3) which I have not set up using Docker Machine, each one running the v1.12-rc4 Docker daemon.
I run docker swarm init on docker1, which in turn prints a docker swarm join command which I run on both docker2 and docker3. At that point, running docker info on each host contains the Swarm: active line.
It is at this point that the behavior seems to differ from what I used to get with the standalone Swarm container. Especially, running docker network ls will only show me the networks on the local host, and when trying to create an overlay network, it does not seem like worker nodes are aware of it (i.e. it does not show up on their docker network ls.)
I feel like I have missed out on some important information relating to the workings of the Swarm Mode as opposed to the Swarm container.
What is the correct way of setting up such a cluster without Docker Machine on Docker 1.12 while getting the overlay network feature?
I too thought this was an issue when I first started using it.
This works a little differently in 1.12rc4 - when you deploy a container to your swarm with that network attached to it, it should then create the network on the other nodes as well.
Hope this helps!
Issue
You are using the docker command (used to communicate with your localhost Docker daemon) and not the "swarm" command (used to communicate with the Swarm master).
Solution
It depends on the command you used to start Swarm.
A full step-by-step tutorial (including details on how to deploy an overlay network) is detailled on this answer. I'm sure that reading this will help you ;)
With a network scope of swarm, the network is only propagated to worker nodes on an as-needed basis. If you create a service using that network, and it gets scheduled on that worker node, the network will show up in the docker network ls.
With the now-upcoming 1.13 release, you can get a network that has similar behavior to the non-swarm networks by doing docker network create --attachable .... That network will be valid for both services and normal containers, and will be available to all members of the cluster. As of 1.13.0-rc2, those don't seem to show up in the output of docker network ls.
Okay, here is my situation:
I created a cluster of docker swarm using docker machine. I can deploy any container, etc. So basically everything is working fine. My question right now is how to give access to the cluster to someone else. I want other people to deploy container on that cluster using docker-compose.
Docker machine configures the docker engine on each node to be secured using TLS:
https://docs.docker.com/engine/security/https/
The client configuration can be seen when running the "docker-machine config" command, for example the following settings are used to access the remote docker host:
--tlsverify
--tlscacert="~/.docker/machine/certs/ca.pem"
--tlscert="~/.docker/machine/certs/cert.pem"
--tlskey="~/.docker/machine/certs/key.pem"
-H=tcp://....
It's the files under ~/.docker/machine/certs that are needed by other users who want to connect to your swarm.
I expect that docker will eventually create some form of user authentication and authorization.
Currently I have a bunch of RHEL7 VMs running on RackSpace and want to deploy docker swarm for testing purpose. The Docker Docs only describes the method to deploy docker swarm by using docker machine.
Question:
Since VirtualBox cannot be used in VMs, are any other ways such that I can directly deploy docker swarm on my VMs without using docker machine?
In fact Docker documentation offers you how to set up a swarm cluster 'manually' without using docker-machine: Create a swarm for development
I think that this full step-by-step tutorial might be useful.
It details how to deploy Swarm with a multi-hosts network, without Docker-machine by using consul and suggest two different means for the Swarm agent discovery (static file and token).
I'd like to understand the communication mechanism between the Docker Swarm Manager and the Docker Swarm Agents :
The Swarm Manager generates a token.
The Swarm Agents are generated, with this token passed to them. (and their own IP)
Now that the Manager needs to give instructions to the agents, how was it informed that the agents were existing to these IPs ?
Hypotesis :
Does the Agents register themselves on some docker.com server with their token, and the Manager gets their addresses from it using the same token ?
Thank you
Options are described in the doc here:
https://docs.docker.com/swarm/discovery/
In this example I use the hosted discovery with Docker Hub. There are other options like a static file, consul, etcd etc.
You create your docker cluster:
docker run -rm swarm create
This will give you a token to be used as your cluster id: e4802398adc58493...longtoken
You register one/multiple docker host(s) with your cluster
docker run -d swarm join --addr=172.17.42.10:2375 token://e4802398adc58493...longtoken
The ip address provided is the address of your docker host node.
This is how the future manager will know about agents/nodes
You deploy the swarm manager to any of your docker host (let's say 172.17.42.10:2375, the same one I used to create the swarm and register my first docker host)
docker run -d -p 9999:2375 swarm manager token://e4802398adc58493...longtoken
To use the cluster you set the DOCKER_HOST to the ip address and port of your swarm manager
export DOCKER_HOST="tcp://172.17.42.10:2375"
Using something like docker info should now return information about nodes in your cluster.