Native Docker Clustering with Swarm

Swarm health

Swarm health depends, essentially, on the availability of the nodes in cluster and on the reliability of the managers (odd number, available, up).

Nodes can be listed with the usual:

docker node ls

This can use the --filter option to filter the output. For example:

docker node ls --filter name=manager # prints nodes named *manager*
docker node ls --filter "type=mysql" # prints nodes with a label 
    type tagged "mysql"

To get details about a specific node, use inspect as shown:

docker inspect worker1

Also, filtering options are available to extract specific data from the output JSON:

docker node inspect --format '{{ .Description.Resources }}' worker2
{1000000000 1044140032}

Outputting the number of cores (one) and the quantity of assigned ...