Docker Networking Architecture is based on Container Network Model (CNM)
Refer Here for the docker container networking article
Cluster
A server cluster is group of two or more nodes (servers), that run in parallel to acheive a common goal
A cluster functions as if it were a single system. A user accessing the cluster should not need to know whether the system is a cluster or individual machine
Benifits:
High Availability
Load Balancing
Scaling
Performance
To manage clusters we generally use cluster orchestration software
Container Orchestration Softwares
Docker Swarm
Kubernetes
Mesos
Using Container Orchestration Softwares, we enable
multi node setups
we express the desired state rather than commands to create containers
Generally Orchestration softwares have two kinds of nodes
master nodes (manager)
nodes (worker)
To decide which node is manager there are consensus algorithms like RAFT etc which will choose the manager by election.
Create 3 ubuntu instances and install docker in them
explore swarm command line
Note the output
Swarm initialized: current node (4zbhonvbfzpzs2dzbbgjcmfz3) is now a manager.
To add a worker to this swarm, run the following command:
docker swarm join --token SWMTKN-1-02wrpqrep3ytgxynjurslwjseu4898o1vvbi0cozh00eth7ova-aswifi8z4zrdwmnl51nzyd7li 172.31.7.10:2377
To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions.
When the swarm is initialized docker will create an overlay network
Docker has one more subcommand node
Basic interaction diagram
In swarm we create services
Note: Sending the image to docker hub
For experimentation lets use the container image shaikkhajaibrahim/qttestapp:1.0Refer Here
Create a service using test app docker service create --name testapp --replicas 2 --publish published=5001,target=5000 shaikkhajaibrahim/qttestapp:1.0
