nsqd: "unhealthy mode" when diskqueue writes fail #422
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opening this up for discussion @jehiah, check out the commit |
| io.WriteString(w, "OK") | ||
| if s.context.nsqd.IsHealthy() { | ||
| w.Header().Set("Content-Length", "2") | ||
| io.WriteString(w, "OK") |
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I think OK and UNHEALTHY don't really make sense here. They are not exactly opposites. How about either HEALTHY and UNHEALTHY or OK and NOK.
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I wanted to preserve the existing OK response. I'm fine with NOK as an alternate.
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LGTM. squash? |
jehiah
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Jul 28, 2014
nsqd: "unhealthy mode" when diskqueue writes fail
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Hailo reported an issue where
nsqdcould not write to a failed ephemeral disk on EC2 but the node continued to acceptPUB.In this scenario,
nsqdshould enter an "unhealthy mode" wherePUBs are rejected until the issue can be investigated.This feedback mechanism to publishers is crucial for them to be able to attempt delivery to another (healthy) node in a cluster or react to this condition in some other way.
Initially, I don't think it's necessary for it to attempt to "heal" itself. I imagine that in most cases you would want to restart the node anyway, which would clear this state.
cc @boyand