Stanislav Kozlovski created KAFKA-7790:
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Summary: Trogdor - Does not time out tasks in time
Key: KAFKA-7790
URL: https://issues.apache.org/jira/browse/KAFKA-7790
Project: Kafka
Issue Type: Improvement
Reporter: Stanislav Kozlovski
Assignee: Stanislav Kozlovski
All Trogdor task specifications have a defined `startMs` and `durationMs`.
Under conditions of task failure and restarts, it is intuitive to assume that a
task would not be re-ran after a certain time period.
Let's best illustrate the issue with an example:
{code:java}
startMs = 12PM; durationMs = 1hour;
# 12:02 - Coordinator schedules a task to run on agent-0
# 12:45 - agent-0 process dies. Coordinator's heartbeats to agent-0 fail.
# 12:47 - agent-0 comes back up. Coordinator's heartbeats pass and it
re-schedules tasks that are not running in agent-0
# 13:20 - agent-0 process dies.
# 13:22 - agent-0 comes back up. Coordinator re-schedules task{code}
This can result in an endless loop of task rescheduling. If there are more
tasks scheduled on agent-0 (e.g a task scheduled to start each on hour), we can
end up in a scenario where we overwhelm the agent with tasks that we would
rather have dropped.
h2. Changes
We propose that the Trogdor Coordinator does not re-schedule a task if the
current time of re-scheduling is greater than the start time of the task and
its duration combined. More specifically:
{code:java}
if (currentTimeMs < startTimeMs + durationTimeMs)
scheduleTask()
else
failTask(){code}
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