DockerService.txt

Service
--1
docker run -it alpine ping 172.31.15.233
docker service --help
 docker service create --name myservice -d  alpine ping 172.31.15.233
docker service inspect <<service name>> | less
docker service logs <<service name>>


--2
 docker service create --name myservice -d --replicas 4 alpine ping 172.31.15.233
 docker service ps myservice
 remove containers on one of the worker node and find the status of the service

--3
   docker service create \
>   --name=viz \
>   --publish=8080:8080/tcp \
>   --constraint=node.role==manager \
>   --mount=type=bind,src=/var/run/docker.sock,dst=/var/run/docker.sock \
>   dockersamples/visualizer

--4
   docker service scale myservice=2
   docker service scale myservice=5
   docker service rm myservice
--5
  docker service --name webservice create -d -p 80:80 nginx
  now you can access it on any worker node
--6
  docker service create --name webservice -d --mode=global --publish=80:80 nginx
  remove a woker node and check the visualizer
  add it again you will find the one replica is created on the worker node
--7 labels and constraint

  docker service create --name webservice -d --constraint="node.role==manager" --publish=80:80 nginx
  docker srevice scale webservice=2  
  Check the visualizer
  docker service create --name webservice -d  --constraint="node.role==worker"  --publish 80:80 nginx
  
  docker node update --label-add="webserver=true" worker01
  docker service create --name webservice -d --constraint="node.labels.webserver==true" --publish 80:80 nginx
  if we create same label to worker02 will the load shifted to worker 02 or not ans is not because you have to se the labels upfront
  
  now create the labels on engine level
  
  goto worker node2
  vi /etc/docker/daemon.json
  
{
   "labels": ["name=testserver"]
}

create service on label server
docker service create --name webservice1 -d --constraint="engine.labels.name==testserver" --publish 84:80 nginx

--8 node availbility
docker node update --availability=pause worker02
now the new containers will not be creating on worker02
docker node update --availability=active worker02

docker node update --availability=drain worker02  # now the nodes are moved to other worker nodes or manager nodes


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