CODEWITHSUNDEEP
dockerdocker-swarm
JiaMing Lin
JiaMing Lin

Reputation: 1082

Clusterized Docker and Managed by Swarm

I am new in Docker, and I was wondering a question today. I know there are spread and binpack strategies which are intends to balance the "work load". But is there any way to provision the containers like the following topology by using Docker, Swarm?

enter image description here

Or should I customize the scheduler? Or is there any suitable cluster management tool? And is there any suggestion?

Upvotes: 1

Views: 286

Answers (1)

abronan
abronan

Reputation: 3439

Update: This answer applies to the legacy docker/swarm and not to the new Swarm mode available since docker 1.12

You can achieve this with Swarm through labels when starting docker daemons on those racks/machines.

Setup the Docker Daemons with labels

Assuming we have this topology:

rack1
  |___ node1

rack2
  |___ node2
  |___ node3

We can setup the docker daemons with custom labels to reflect this:

Node 1 on Rack 1

docker --tlsverify --tlscacert=ca.pem --tlscert=server-cert.pem --tlskey=server-key.pem -H tcp://0.0.0.0:2376 -d --label rack=rack1 --label machine=node1`

Node 2 on Rack 2

docker --tlsverify --tlscacert=ca.pem --tlscert=server-cert.pem --tlskey=server-key.pem -H tcp://0.0.0.0:2376 -d --label rack=rack2 --label machine=node2

Node 3 on Rack 2

docker --tlsverify --tlscacert=ca.pem --tlscert=server-cert.pem --tlskey=server-key.pem -H tcp://0.0.0.0:2376 -d --label rack=rack2 --label machine=node3

Using constraints

With Swarm you can then use constraints to pick up a location for your containers. In this example, we only use the subset of nodes on Rack 1 to schedule our container:

docker run -d -P -e constraint:rack==rack1 --name web nginx

Providing that you have multiple nodes per rack (with rack2 for example) you can also chain constraints. In the next example, we pin the container to node3 which is located on rack2.

docker run -d -P -e constraint:rack==rack2 -e constraint:node==node3 --name web nginx

Upvotes: 3

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