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On this occasion I will introduce to friends about docker swarm


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to facilitate the friends in understanding about Docker swarm, here I show images in the system of traditional mode


so friends can meihat difference between the traditional fashion by a swarm mode


and also the advantages of a docker swarm compared to the traditional mode


in a system of traditional if friends If you have 3 web or application instances


running on 3 servers, you need an external load balancer.


To distribute traffic to the 3 servers


and how to deploy the application, you have to upload it to the 3 servers


or run docker on each. the server


Well, the difference with docker swarm,


if you use it i docker swarm, to deploy your application, just deploy it in the manager.


Later, the manager will distribute or replicate your application


to the workers in the docker swarm


or to the manager itself according to the number of replicas that you already have. friends define


And 1 advantage of docker swarm is that


there is an internal load-balancer feature.


So, each node can function as a load-balancer so that you don't need an external load-balancer anymore.


For example, if we create a web service that publishes to port 8080 with 2 replicas of


Replica the first running on node1, the second on node2


So, we can access it from any node


When a request to node1 is on port 8080


Then, the request will be load-balanced to the web container on node1 nor node2


Likewise if we access port 8080 on node2 and node 3


Even though on node3 there is no web replica running there


But still, if the request goes to node3 on port 8080


then request The st will be load-balanced to the web replicas on node1 and on node2


So each node can function as a load-balancer


So what is a docker swarm?


docker swarm is an orchestration feature owned by the docker engine, it


is a cluster consisting of a docker host or called a node


, each node can have a role as a manager or worker


among the docker swarm features, the first is cluster management


Yes course for Docker swarm is a cluster, the cluster must have its management


which of the two is a declarative service model of


meaning, "you tell swarm manager what you want, not what to do"


So what you want. suppose you want a service with 2 replicas, port 8080


so it's not how to deploy it. that's the docker manager's business.


The third thing is scaling. So, your services can be scaled


freely, you want to scale-up to any extent


according to the available resources, of course.


The fourth is service discovery.


So, between services in the docker swarm, you can communicate with each other by mentioning the name of the service.


Now, where is the service running? , what ip is it, you don't need to know the


docker swarm that will resolve the ip


The next feature is load balancing


As I explained earlier


that every node in the docker swarm


can function as a load balancer


and the last one is rolling updates


so when there is an update in the deployment


that is carried out, it is not updated as a whole,


but the replicas are updated one by one