Benjamin Bannier created MESOS-8058:
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Summary: Agent and master can race when updating agent state
Key: MESOS-8058
URL: https://issues.apache.org/jira/browse/MESOS-8058
Project: Mesos
Issue Type: Bug
Components: agent
Affects Versions: 1.5.0
Reporter: Benjamin Bannier
Assignee: Benjamin Bannier
Priority: Critical
In {{2af9a5b07dc80151154264e974d03f56a1c25838}} we introduce the use of
{{UpdateSlaveMessage}} for the agent to inform the master about its current
total resources. Currently we trigger this message only on agent registration
and reregistration.
This can race with operations applied in the master and communicated via
{{CheckpointResourcesMessage}}.
Example:
1. Agent ({{cpus:4(\*)}} registers.
2. Master is triggered to apply an operation to the agent's resources, e.g., a
reservation: {{cpus:4(\*) -> cpus:4(A)}}. The master applies the operation to
its current view of the agent's resources and sends the agent a
{{CheckpointResourcesMessage}} so the agent can persist the result.
3. The agent send the master an {{UpdateSlaveMessage}}, e.g., {{cpus:4(\*)}}
since it hasn't received the {{CheckpointResourcesMessage}} yet.
4. The master processes the {{UpdateSlaveMessage}} and updates its view of the
agent's resources to be {{cpus:4(\*)}}.
5. The agent processes the {{CheckpointResourcesMessage}} and updates its view
of its resources to be {{cpus:4(A)}}.
6. The agent and the master have an inconsistent view of the agent's resources.
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