Use roundRobin balancing even if only one hostname #1329
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If you run jaeger-agent with `--reporter.grpc.host-port dns:///jaeger-collector-hostname:14250` (note the `dns:///` part!), the GRPC client resolves the given hostname to one or more IPs and can load balance among the backend addresses it finds. It even looks up and obeys SRV records, if they exist. This change makes jaeger-agent use round-robin load balancing in that situation, rather than the default of `pick_first`. If there is only one backend, or the user doesn't explicitly put `dns:///` before the hostname, this will have no effect. Signed-off-by: Benjamin Staffin <benley@gmail.com>
benley
requested review from
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jpkrohling,
objectiser,
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In time: you'd get bonus points if you could add this to the documentation and/or to the help options. |
How does this look? jaegertracing/documentation#212 |
yurishkuro
approved these changes
Feb 12, 2019
ghost
assigned 
#213 is closely related but I'm not sure if this really closes it. We're adding some much-needed functionality for grpc balancing but DNS service discovery isn't going to be as reliable as, say, Zookeeper or etcd or Kubernetes API watches for noticing when the set of backends changes.
Sure, I will do that! |
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Feb 15, 2019
If you run jaeger-agent with `--reporter.grpc.host-port dns:///jaeger-collector-hostname:14250` (note the `dns:///` part!), the GRPC client resolves the given hostname to one or more IPs and can load balance among the backend addresses it finds. It even looks up and obeys SRV records, if they exist. This change makes jaeger-agent use round-robin load balancing in that situation, rather than the default of `pick_first`. If there is only one backend, or the user doesn't explicitly put `dns:///` before the hostname, this will have no effect. Signed-off-by: Benjamin Staffin <benley@gmail.com> Signed-off-by: Iori Yoneji <fivo.11235813@gmail.com>
iori-yja
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Feb 15, 2019
If you run jaeger-agent with `--reporter.grpc.host-port dns:///jaeger-collector-hostname:14250` (note the `dns:///` part!), the GRPC client resolves the given hostname to one or more IPs and can load balance among the backend addresses it finds. It even looks up and obeys SRV records, if they exist. This change makes jaeger-agent use round-robin load balancing in that situation, rather than the default of `pick_first`. If there is only one backend, or the user doesn't explicitly put `dns:///` before the hostname, this will have no effect. Signed-off-by: Benjamin Staffin <benley@gmail.com>
iori-yja
pushed a commit
to iori-yja/jaeger
that referenced
this pull request
Feb 15, 2019
If you run jaeger-agent with `--reporter.grpc.host-port dns:///jaeger-collector-hostname:14250` (note the `dns:///` part!), the GRPC client resolves the given hostname to one or more IPs and can load balance among the backend addresses it finds. It even looks up and obeys SRV records, if they exist. This change makes jaeger-agent use round-robin load balancing in that situation, rather than the default of `pick_first`. If there is only one backend, or the user doesn't explicitly put `dns:///` before the hostname, this will have no effect. Signed-off-by: Benjamin Staffin <benley@gmail.com>
iori-yja
pushed a commit
to iori-yja/jaeger
that referenced
this pull request
Feb 15, 2019
If you run jaeger-agent with `--reporter.grpc.host-port dns:///jaeger-collector-hostname:14250` (note the `dns:///` part!), the GRPC client resolves the given hostname to one or more IPs and can load balance among the backend addresses it finds. It even looks up and obeys SRV records, if they exist. This change makes jaeger-agent use round-robin load balancing in that situation, rather than the default of `pick_first`. If there is only one backend, or the user doesn't explicitly put `dns:///` before the hostname, this will have no effect. Signed-off-by: Benjamin Staffin <benley@gmail.com>
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Which problem is this PR solving?
Short description of the changes
--reporter.grpc.host-port dns:///jaeger-collector-hostname:14250(note thedns:///part!), the GRPC client resolves the given hostname to one or more IPs and can load balance among the backend addresses it finds. It even looks up and obeys SRV records, if they exist. This change makes jaeger-agent use round-robin load balancing in that situation, rather than the default ofpick_first. If there is only one backend, or the user doesn't explicitly putdns:///before the hostname, this will have no effect.See https://www.marwan.io/blog/grpc-dns-load-balancing for more details.
Question: should this
dnsresolver style be the default behaviour? That can be done easily as well.