Docker Swarm

Docker swarm is a technique to create and maintain a cluster of Docker Engines

Service deployed in any node can be accessed on other nodes in the same clusters

This command creates a network of Docker engines/ hosts to execute containers in parallel (for scaling up & high availability).

Docker Swarm is an orchestration tool like Kubernetes.

Features:

1. High-Availability of services
2. Auto load-balancing
3. Decentralised Access
4. Easy to Scale-up deployments

Docker Swarm

**docker swarm init --advertise-addr <IP_address_manager_machine> ->** #Initalize Swarm as a Manager node

**docker swarm join <token> ->** # To join a swarm cluster as a worker node, token is given by the manager

**docker swarm join-token ->** # re-generate worker token at manager end

**docker swarm leave ->** # Leave the docker swarm cluster as a worker

**docker swarm leave --force ->** # Leave the docker swarm cluster as a manager

**docker node ps ->** # list services in nodes

**docker node rm <id> ->** # remove node

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# Commands run on only Managers

**docker node ls ->** # list the nodes

**# Docker Services are used to control any existing Docker Service (Container/ Compose/ Swarm/ Others ...)**

**docker service ls ->** #list services running in the cluster

**docker service ps <name> ->** # list nodes in which this service is running

**docker service scale <name>=5 ->** # scale services to increases replicas

**docker service create --name <name> <image-name> ->** # create new service

**--mode global** -> # flag used to deploy service on all nodes

**--replicas 2 ->** # Deploy service on only 2 nodes and manger will auto-decide the healthy nodes to deploy

**docker service rm <name> ->** # remove service

**docker service stop

docker service logs**