Swarm Rescheduling
You can set recheduling policies with Docker Swarm. A rescheduling policy determines what the Swarm scheduler does for containers when the nodes they are running on fail.
Rescheduling policies
You set the reschedule policy when you start a container. You can do this with the reschedule environment variable or the com.docker.swarm.reschedule-policies label. If you don’t specify a policy, the default rescheduling policy is off which means that Swarm does not restart a container when a node fails.
To set the on-node-failure policy with a reschedule environment variable:
1 | $ docker run -d -e reschedule:on-node-failure redis |
To set the same policy with a com.docker.swarm.reschedule-policies label:
1 | $ docker run -d -l 'com.docker.swarm.reschedule-policies=["on-node-failure"]' redis |
Review reschedule logs
You can use the docker logs command to review the rescheduled container actions. To do this, use the following command syntax:
1 | docker logs SWARM_MANAGER_CONTAINER_ID |
When a container is successfully rescheduled, it generates a message similar to the following:
1 2 | Rescheduled container 2536adb23 from node-1 to node-2 as 2362901cb213da321Container 2536adb23 was running, starting container 2362901cb213da321 |
If for some reason, the new container fails to start on the new node, the log contains:
1 | Failed to start rescheduled container 2362901cb213da321 |
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