Question for the community: Is it possible or has anyone been able to achieve limiting of parallel tasks executions across multiple workflows? For example

Workflow A

runs

Task B

10 times. If we run

Workflow A

100 times it will run a total of 1,000

Task B

's. Is there a way to make it so only 500 of

Task B

max can run at any single time? Also is there a limit to how long a task can sit and wait for a spot to run before the job fails or is dropped? For example an instance of

Task B

is the thousandth one, how long can it wait before all the ones before it are done and a spot opens up for it to execute before its kicked out, or is there even a limit?

Similar to my previous question

Is it possible or has anyone been able to achieve limiting of parallel tasks executions across multiple workflows?

Should be possible with

maxParallelism

. https://docs.flyte.org/en/latest/deployment/configuration/performance.html#worst-case-workflows-poison-pills-max-parallelism

Also is there a limit to how long a task can sit and wait for a spot to run before the job fails or is dropped?

This is configurable: https://docs.flyte.org/en/latest/deployment/configuration/generated/flyteadmin_config.html#config-defaultdeadlines. As per https://github.com/flyteorg/flyte/issues/2933 issue,

node-active-deadline

defaults to 48h but the docs states that the default value is 0s. @hallowed-mouse-14616, can you shed some light on this?

Thanks for the ping @tall-lock-23197! To limit parallel execution of tasks across multiple workflows the only construct we currently have

cache_serialize

which, given a cachable task, ensures that only a single instance of the task runs at a time. If two instances are started simultaneously, one will wait until the other is finished and reuse the cached results. It doesn't sound like this is quite what you're looking for, we would have to think on this - but I suspect an elegant solution could be a bit of work. Regarding the

node-active-deadline

, the previous default value was

48h

but users with long-running tasks exhibited some concern over unexpected terminations. So we decided that this default should be `0s`(meaning unlimited).