CPP-879 Allow remote hosts to come back up #463
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When a host comes back up after being down, a request processor (unlike a control connection) only notifies the load balancing policy if the host is not ignored. Sadly some policies ignore remote hosts that are down. In combination, this means that remote hosts can never be used by a request (processor) after having once gone down. This fix resolves this, by always notifying a policy of all host-up events, regardless of the distance of that host.
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Nice, simple fix. LGTM! |
kw217
changed the title
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Thanks for the PR. Sorry for the delay, I've been out. I'll work on investigating this issue today. |
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Hi @mpenick, could we have a minor release with this PR. Seems like an important one. |
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Change looks great. Thanks again. |
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@accelerated yes, highly likely. You're right. This is release worthy. |
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Brilliant - thank you both! |
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@kw217 @accelerated This fix is in the recently posted release v2.14.1. |
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When a host comes back up after being down, a request processor (unlike a control connection) only notifies the load balancing policy if the host is not ignored.
Sadly some policies ignore remote hosts that are down.
In combination, this means that remote hosts can never be used by a request (processor) after having once gone down.
This fix resolves this, by always notifying a policy of all host-up events, regardless of the distance of that host.
I've tested this locally, and it has the desired effect. My test case is:
In the last step, in 2.14.0, instead I observe that traffic continues to fail. Logs and netstat reveal the control connection is up to the remote DC, but it is not used by the request processor. This PR fixes this, so that traffic does go to the remote DC.