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https://issues.apache.org/jira/browse/JCLOUDS-1203?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Andrew Gaul updated JCLOUDS-1203:
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Component/s: jclouds-compute
> aws-ec2 rate-limiting causes provisioning to fail: need longer back-off/retry
> -----------------------------------------------------------------------------
>
> Key: JCLOUDS-1203
> URL: https://issues.apache.org/jira/browse/JCLOUDS-1203
> Project: jclouds
> Issue Type: Bug
> Components: jclouds-compute
> Affects Versions: 1.9.2, 2.0.0
> Reporter: Aled Sage
> Labels: aws-ec2
>
> TL;DR: increase default retry/back-off to 500ms and 6 retries.
> In Apache Brooklyn (which uses jclouds), we hit {{Request limit exceeded}}
> when provisioning VMs in aws-ec2 [1]. We were provisioning multiple machines
> concurrently: different threads were independently calling
> {{createNodesInGroup}}. The default exponential backoff and retry within
> jclouds wasn't enough.
> My understanding is that AWS will rate-limit based on the nature (as well as
> number) of API calls. For example, if creating/modifying security groups is a
> more expensive operation (from AWS's perspective) than a simple poll for a
> machine's state, then those requests would cause rate-limiting sooner.
> Within jclouds, the defaults are {{retryCountLimit = 5}} and {{delayStart =
> 50ms}} (see [2]).
> This means we retry with the back-offs being (approximately) 50ms, 100ms,
> 200ms, 400ms and 500ms.
> We overrode the defaults to be 500ms and 6 retries, and could then
> successfully provision 20 VMs concurrently. Six of the 20 calls to
> {{RunInstances}} were rate-limited. It took several retries before the
> request was accepted, having to back off for more than 4 seconds in some
> cases.
> At worst, the existing short back-off may make things worse (the overly
> aggressive retry might cause other concurrent calls to also be rate-limited).
> At best, the short back-off just isn't long enough so that particular VM
> provisioning fails. For example, if AWS uses a leaky bucket algorithm [3]
> then hopefully some requests would keep on getting through. But AWS don't
> publicise such details of their algorithm/implementation, I believe.
> [1] https://issues.apache.org/jira/browse/BROOKLYN-394
> [2]
> https://github.com/jclouds/jclouds/blob/rel/jclouds-2.0.0/core/src/main/java/org/jclouds/http/handlers/BackoffLimitedRetryHandler.java#L81-#L87
> [3] http://en.wikipedia.org/wiki/Leaky_bucket
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