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Implement trying to **TO** address

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Signed-off-by: Miek Gieben <miek@miek.nl>
This commit is contained in:
Miek Gieben
2020-03-05 11:02:54 +01:00
parent 2d67767764
commit 50184d718b
3 changed files with 32 additions and 11 deletions
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24
plugin/traffic/README.md
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@@ -179,24 +179,36 @@ This will load balance any names under `lb.example.org` using the data from the
localhost on port 18000. The node ID will be `test-id` and no TLS will be used. Assuming a
management server returns config for `web` cluster, you can query CoreDNS for it, below we do an
address lookup, which returns an address for the endpoint. The second example shows a SRV lookup
which returns all endpoints.
which returns all endpoints. The third shows what gRPC will ask for when looking for load balancers.
~~~ sh
$ dig @localhost web.lb.example.org +noall +answer
$ dig web.lb.example.org +noall +answer
web.lb.example.org. 5 IN A 127.0.1.1
$ dig @localhost web.lb.example.org SRV +noall +answer +additional
$ dig web.lb.example.org SRV +noall +answer +additional
web.lb.example.org. 5 IN SRV 100 100 18008 endpoint-0.web.lb.example.org.
web.lb.example.org. 5 IN SRV 100 100 18008 endpoint-1.web.lb.example.org.
web.lb.example.org. 5 IN SRV 100 100 18008 endpoint-2.web.lb.example.org.
endpoint-0.web.lb.example.org. 5 IN A 127.0.1.1
endpoint-1.web.lb.example.org. 5 IN A 127.0.1.2
endpoint-2.web.lb.example.org. 5 IN A 127.0.2.1
$ dig _grpclb._tcp.web.lb.example.org SRV +noall +answer +additional
_grpclb._tcp.web.lb.example.org. 5 IN SRV 100 100 18008 endpoint-0.xds.lb.example.org.
_grpclb._tcp.web.lb.example.org. 5 IN SRV 100 100 18008 endpoint-1.xds.lb.example.org.
_grpclb._tcp.web.lb.example.org. 5 IN SRV 100 100 18008 endpoint-2.xds.lb.example.org.
endpoint-0.xds.lb.example.org. 5 IN A 10.0.1.1
endpoint-1.xds.lb.example.org. 5 IN A 10.0.1.2
endpoint-2.xds.lb.example.org. 5 IN A 10.0.2.1
~~~
## Bugs
Priority and locality information from ClusterLoadAssignments is not used. Multiple **TO** addresses
is not implemented. Credentials are not implemented.
Priority and locality information from ClusterLoadAssignments is not used. Credentials are not
implemented.
Load reporting is not supported for the following reason: A DNS query is done by a resolver.
Behind this resolver (which can also cache) there may be many clients that will use this reply. The
@@ -204,6 +216,8 @@ responding server (CoreDNS) has no idea how many clients use this resolver. So r
+1 on the CoreDNS side can results in anything from 1 to 1000+ of queries on the endpoint, making
the load reporting from *traffic* highly inaccurate.
Bootstrapping is not fully implemented, *traffic* will connect to the first working **TO** addresss,
but then stops short of re-connecting to he endpoints is received for the management **CLUSTER**.
## Also See