Creating a docker swarm cluster:
The docker swarm can be created by using the following command:
The syntax is defined as follows:
docker swarm init --advertise-addr [available interface IP adress]
The –advertise-addr is used to explicitly define the docker swarm advertise ip. If you have a single interface this option will not be needed but will be real handy if you have more than 1 active public accessible interfaces.
Let us initialize our docker swarm environment.
[vamshi@docker-swarm ~]$ docker swarm init --advertise-addr 10.100.0.20 Swarm initialized: current node (nodeidofmastercdq7nmmq3kcmb5l85k2e) is now a manager. To add a worker to this swarm, run the following command: docker swarm join \ --token SWMTKN-1-verylongstringofcharactercontainingthedockerswarmjoinstring-70bouyqwhfgdcgtw6o0fw6wup \ 10.100.0.20:2377 To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions.
The docker swarm creation can be viewed from the docker info command as follows:
[vamshi@docker-swarm ~]$ docker info | grep -C 2 Swarm Volume: local Network: bridge host macvlan null overlay Swarm: active NodeID: nodeidofmastercdq7nmmq3kcmb5l85k2e Is Manager: true
The docker swarm explicitly uses the overlay and macvlan to enable the interhost network connectivity between the container over a swarm network
How to get the docker swarm join token:
This command can come in very handy when you forgot your docker swarm token and you need to join a new docker node to this docker swarm cluster.
[vamshi@docker-swarm ~]$ docker swarm join-token manager -q SWMTKN-1-verylongstringofcharactercontainingthedockerswarmjoinstring-70bouyqwhfgdcgtw6o0fw6wup