Docker container RestartCount not incrementing

Question

Test

def test_can_pop_new_container(self):
    config = {
        'ip': '10.49.0.2',
        'subnet': '10.49.0.0/16',
        'gateway': '10.49.0.202',
        'vlan': 102,
        'hostname': 'test-container',
    }
    container = container_services.pop_new_container(config, self.docker_api)

    inspection = self.docker_api.inspect_container(container.get('Id'))
    print('before', inspection.get('RestartCount'), inspection.get('StartedAt'))
    container_services.restart(container, self.docker_api)
    new_inspection = self.docker_api.inspect_container(container.get('Id'))
    print('after', new_inspection.get('RestartCount'), new_inspection.get('StartedAt'))

Code

def restart(container, docker_client):
    return docker_client.restart(container.get('Id'))

Output

From the test I get

before 0 None
after 0 None

From docker ps that confirm the container restarted.

CONTAINER ID        IMAGE                                                 COMMAND                  CREATED             STATUS              PORTS               NAMES
86f16438ffdd        docker.akema.fr:5000/coaxis/coaxisopt_daemon:latest   "/usr/bin/supervis..."   28 seconds ago      Up 17 seconds                           confident_dijkstra

Question

Why is RestartCount still at 0 then? Am I using the wrong field?

Answer 1

As already indicated in the comment, the field RestartCount is used in the context of Restart Policies to keep track of restart attempts in case of failures.

It will not be incremented in case of user-initiated restarts.

You can look at docker events to keep track on normal container restarts. This is also available for dockerpy.