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AWS peer discovery: add multi-hostname path support #14705

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c0c79bf
AWS peer discovery: add multi-hostname path support
BenAtAmazon Oct 7, 2025
2a3274a
Update deps/rabbitmq_peer_discovery_aws/priv/schema/rabbitmq_peer_dis…
lukebakken Oct 22, 2025
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30 changes: 30 additions & 0 deletions deps/rabbitmq_peer_discovery_aws/priv/schema/rabbitmq_peer_discovery_aws.schema
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Original file line number Diff line number Diff line change
Expand Up @@ -108,3 +108,33 @@ fun(Conf) ->
Value -> rabbit_peer_discovery_util:as_list(Value)
end
end}.

%% hostname_paths (multiple paths support)

{mapping, "cluster_formation.aws.hostname_path.$number", "rabbit.cluster_formation.peer_discovery_aws.aws_hostname_paths", [
{datatype, string}
]}.

{translation, "rabbit.cluster_formation.peer_discovery_aws.aws_hostname_paths",
fun(Conf) ->
case cuttlefish_variable:filter_by_prefix("cluster_formation.aws.hostname_path", Conf) of
[] ->
cuttlefish:unset();
L ->
%% Extract and sort numbered paths (hostname_path.1, hostname_path.2, etc.)
L1 = lists:map(
fun ({["cluster_formation", "aws", "hostname_path", N], V}) ->
case string:to_integer(N) of
{I, ""} ->
{I, V};
_ ->
cuttlefish:invalid(io_lib:format("Cannot convert ~p to an integer", [N]))
end;
(Other) ->
cuttlefish:invalid(io_lib:format("~p is invalid", [Other]))
end, L),
[rabbit_peer_discovery_util:as_list(V) || {_, V} <- lists:sort(L1)]
end
end}.


99 changes: 79 additions & 20 deletions deps/rabbitmq_peer_discovery_aws/src/rabbit_peer_discovery_aws.erl
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Original file line number Diff line number Diff line change
Expand Up @@ -62,6 +62,11 @@
env_variable = "AWS_HOSTNAME_PATH",
default_value = ["privateDnsName"]
},
aws_hostname_paths => #peer_discovery_config_entry_meta{
type = list,
env_variable = "AWS_HOSTNAME_PATHS",
default_value = []
},
aws_use_private_ip => #peer_discovery_config_entry_meta{
type = atom,
env_variable = "AWS_USE_PRIVATE_IP",
Expand Down Expand Up @@ -318,10 +323,11 @@ get_hostname_name_from_reservation_set([], Accum) -> Accum;
get_hostname_name_from_reservation_set([{"item", RI}|T], Accum) ->
InstancesSet = proplists:get_value("instancesSet", RI),
Items = [Item || {"item", Item} <- InstancesSet],
HostnamePath = get_hostname_path(),
Hostnames = [get_hostname(HostnamePath, Item) || Item <- Items],
Hostnames2 = [Name || Name <- Hostnames, Name =/= ""],
get_hostname_name_from_reservation_set(T, Accum ++ Hostnames2).
HostnamePaths = get_hostname_paths(),
?LOG_DEBUG("AWS peer discovery: processing reservation with ~p instances using hostname paths: ~tp",
[length(Items), HostnamePaths]),
UniqueHostnames = extract_unique_hostnames(HostnamePaths, Items),
get_hostname_name_from_reservation_set(T, Accum ++ UniqueHostnames).

get_hostname_names(Path) ->
case rabbitmq_aws:api_get_request("ec2", Path) of
Expand All @@ -347,31 +353,69 @@ get_hostname_by_tags(Tags) ->
Names
end.

-spec get_hostname_path() -> path().
get_hostname_path() ->
UsePrivateIP = get_config_key(aws_use_private_ip, ?CONFIG_MODULE:config_map(?BACKEND_CONFIG_KEY)),
HostnamePath = get_config_key(aws_hostname_path, ?CONFIG_MODULE:config_map(?BACKEND_CONFIG_KEY)),
FinalPath = case HostnamePath of
["privateDnsName"] when UsePrivateIP -> ["privateIpAddress"];
P -> P
-spec get_hostname_paths() -> [path()].
get_hostname_paths() ->
M = ?CONFIG_MODULE:config_map(?BACKEND_CONFIG_KEY),
UsePrivateIP = get_config_key(aws_use_private_ip, M),
RawPaths = case get_config_key(aws_hostname_paths, M) of
Paths when is_list(Paths), Paths =/= [] ->
?LOG_DEBUG("AWS peer discovery using multiple hostname paths"),
Paths;
_ ->
%% Use single path configuration (including when Paths is [])
SinglePath = get_single_hostname_path_raw(M),
?LOG_DEBUG("AWS peer discovery using single hostname path"),
[SinglePath]
end,
?LOG_DEBUG("AWS peer discovery using hostname path: ~tp", [FinalPath]),
FinalPath.
%% Apply use_private_ip override to all paths consistently
FinalPaths = apply_private_ip_override(RawPaths, UsePrivateIP),
?LOG_DEBUG("AWS peer discovery final hostname paths: ~tp", [FinalPaths]),
FinalPaths.

-spec get_single_hostname_path_raw(map()) -> path().
get_single_hostname_path_raw(ConfigMap) ->
case get_config_key(aws_hostname_path, ConfigMap) of
undefined ->
["privateDnsName"];
P ->
P
end.

-spec apply_private_ip_override([path()], boolean()) -> [path()].
apply_private_ip_override(Paths, UsePrivateIP) ->
apply_private_ip_override(Paths, UsePrivateIP, []).
apply_private_ip_override([], _, Acc) ->
lists:reverse(Acc);
apply_private_ip_override([["privateDnsName"] | Paths], true, Acc0) ->
Acc1 = [["privateIpAddress"] | Acc0],
apply_private_ip_override(Paths, true, Acc1);
apply_private_ip_override([Path | Paths], UsePrivateIP, Acc0) ->
Acc1 = [Path | Acc0],
apply_private_ip_override(Paths, UsePrivateIP, Acc1).

-spec get_hostname(path(), props()) -> string().
get_hostname([], _Props) ->
?LOG_DEBUG("AWS peer discovery: empty hostname path provided"),
""; %% Handle empty paths gracefully
get_hostname(Path, Props) ->
List = lists:foldl(fun get_value/2, Props, Path),
case io_lib:latin1_char_list(List) of
true -> List;
_ -> ""
true ->
?LOG_DEBUG("AWS peer discovery: extracted hostname '~ts' from path ~tp", [List, Path]),
List;
_ ->
?LOG_DEBUG("AWS peer discovery: invalid hostname format from path ~tp, result: ~tp", [Path, List]),
""
end.

-spec get_value(string()|integer(), props()) -> props().
get_value(_, []) ->
[];
get_value(Key, Props) when is_integer(Key) ->
{"item", Props2} = lists:nth(Key, Props),
Props2;
get_value(Key, Props) when is_integer(Key), is_list(Props), length(Props) >= Key, Key > 0 ->
case lists:nth(Key, Props) of
{"item", Props2} -> Props2;
_ -> [] % Malformed data
end;
get_value(Key, _Props) when is_integer(Key) ->
[]; % Out of bounds or empty list
get_value(Key, Props) ->
Value = proplists:get_value(Key, Props),
sort_ec2_hostname_path_set_members(Key, Value).
Expand Down Expand Up @@ -413,3 +457,18 @@ get_tags() ->
maps:from_list(Value);
_ -> Tags
end.

%% Helper functions for multiple hostname paths support

-spec extract_unique_hostnames([path()], [props()]) -> [string()].
extract_unique_hostnames(Paths, Items) ->
?LOG_DEBUG("AWS peer discovery: extracting hostnames using ~p paths for ~p items",
[length(Paths), length(Items)]),
%% Extract all hostnames from all paths for all items
AllHostnames = [get_hostname(Path, Item) || Path <- Paths, Item <- Items],
%% Filter out empty hostnames and remove duplicates
ValidHostnames = [Name || Name <- AllHostnames, Name =/= ""],
UniqueHostnames = lists:uniq(ValidHostnames),
?LOG_DEBUG("AWS peer discovery: extracted ~p total hostnames, ~p valid, ~p unique: ~tp",
[length(AllHostnames), length(ValidHostnames), length(UniqueHostnames), UniqueHostnames]),
UniqueHostnames.
30 changes: 30 additions & 0 deletions ...tmq_peer_discovery_aws/test/config_schema_SUITE_data/rabbitmq_peer_discovery_aws.snippets
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Expand Up @@ -103,5 +103,35 @@
]}
]}
], [rabbitmq_peer_discovery_aws]
},
{aws_hostname_paths_multiple,
"cluster_formation.aws.hostname_path.1 = networkInterfaceSet,2,privateIpAddressesSet,1,privateDnsName
cluster_formation.aws.hostname_path.2 = privateDnsName
cluster_formation.aws.hostname_path.3 = privateIpAddress",
[
{rabbit, [
{cluster_formation, [
{peer_discovery_aws, [
{aws_hostname_paths, [
["networkInterfaceSet", 2, "privateIpAddressesSet", 1, "privateDnsName"],
["privateDnsName"],
["privateIpAddress"]
]}
]}
]}
]}
], [rabbitmq_peer_discovery_aws]
},
{aws_hostname_paths_single_numbered,
"cluster_formation.aws.hostname_path.1 = privateDnsName",
[
{rabbit, [
{cluster_formation, [
{peer_discovery_aws, [
{aws_hostname_paths, [["privateDnsName"]]}
]}
]}
]}
], [rabbitmq_peer_discovery_aws]
}
].
146 changes: 2 additions & 144 deletions deps/rabbitmq_peer_discovery_aws/test/unit_SUITE.erl
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Original file line number Diff line number Diff line change
Expand Up @@ -8,10 +8,10 @@
-module(unit_SUITE).

-compile(export_all).

-include_lib("common_test/include/ct.hrl").
-include_lib("eunit/include/eunit.hrl").


all() ->
[
{group, unit},
Expand All @@ -22,7 +22,6 @@ groups() ->
[
{unit, [], [
maybe_add_tag_filters,
get_hostname_name_from_reservation_set,
registration_support,
network_interface_sorting,
private_ip_address_sorting
Expand All @@ -46,48 +45,7 @@ maybe_add_tag_filters(_Config) ->
{"Filter.1.Name", "tag:region"},
{"Filter.1.Value.1", "us-west-2"}]),
Result = lists:sort(rabbit_peer_discovery_aws:maybe_add_tag_filters(Tags, [], 1)),
?assertEqual(Expectation, Result).

get_hostname_name_from_reservation_set(_Config) ->
ok = eunit:test({
foreach,
fun on_start/0,
fun on_finish/1,
[{"from private DNS",
fun() ->
Expectation = ["ip-10-0-16-29.eu-west-1.compute.internal",
"ip-10-0-16-31.eu-west-1.compute.internal"],
?assertEqual(Expectation,
rabbit_peer_discovery_aws:get_hostname_name_from_reservation_set(
reservation_set(), []))
end},
{"from arbitrary path",
fun() ->
os:putenv("AWS_HOSTNAME_PATH", "networkInterfaceSet,1,association,publicDnsName"),
Expectation = ["ec2-203-0-113-11.eu-west-1.compute.amazonaws.com",
"ec2-203-0-113-21.eu-west-1.compute.amazonaws.com"],
?assertEqual(Expectation,
rabbit_peer_discovery_aws:get_hostname_name_from_reservation_set(
reservation_set(), []))
end},
{"from private IP",
fun() ->
os:putenv("AWS_USE_PRIVATE_IP", "true"),
Expectation = ["10.0.16.29", "10.0.16.31"],
?assertEqual(Expectation,
rabbit_peer_discovery_aws:get_hostname_name_from_reservation_set(
reservation_set(), []))
end},
{"from private IP DNS in network interface",
fun() ->
os:putenv("AWS_HOSTNAME_PATH", "networkInterfaceSet,2,privateIpAddressesSet,1,privateDnsName"),
Expectation = ["ip-10-0-15-100.eu-west-1.compute.internal",
"ip-10-0-16-31.eu-west-1.compute.internal"],
?assertEqual(Expectation,
rabbit_peer_discovery_aws:get_hostname_name_from_reservation_set(
reservation_set(), []))
end}]
}).
?assertMatch(Expectation, Result).

registration_support(_Config) ->
?assertEqual(false, rabbit_peer_discovery_aws:supports_registration()).
Expand Down Expand Up @@ -189,103 +147,3 @@ lock_multiple_nodes(_Config) ->
lock_local_node_not_discovered(_Config) ->
Expectation = {error, "Local node " ++ atom_to_list(node()) ++ " is not part of discovered nodes [me@host]"},
?assertEqual(Expectation, rabbit_peer_discovery_aws:lock([me@host])).

%%%
%%% Implementation
%%%

on_start() ->
reset().

on_finish(_Config) ->
reset().

reset() ->
application:unset_env(rabbit, cluster_formation),
os:unsetenv("AWS_HOSTNAME_PATH"),
os:unsetenv("AWS_USE_PRIVATE_IP").

reservation_set() ->
[{"item", [{"reservationId","r-006cfdbf8d04c5f01"},
{"ownerId","248536293561"},
{"groupSet",[]},
{"instancesSet",
[{"item",
[{"instanceId","i-0c6d048641f09cad2"},
{"imageId","ami-ef4c7989"},
{"instanceState",
[{"code","16"},{"name","running"}]},
{"privateDnsName",
"ip-10-0-16-29.eu-west-1.compute.internal"},
{"dnsName",[]},
{"instanceType","c4.large"},
{"launchTime","2017-04-07T12:05:10"},
{"subnetId","subnet-61ff660"},
{"vpcId","vpc-4fe1562b"},
{"networkInterfaceSet", [
{"item",
[{"attachment", [{"deviceIndex", "1"}]},
{"association",
[{"publicIp","203.0.113.12"},
{"publicDnsName",
"ec2-203-0-113-12.eu-west-1.compute.amazonaws.com"},
{"ipOwnerId","amazon"}]},
{"privateIpAddressesSet", [
{"item", [
{"privateIpAddress", "10.0.15.101"},
{"privateDnsName", "ip-10-0-15-101.eu-west-1.compute.internal"},
{"primary", "false"}
]},
{"item", [
{"privateIpAddress", "10.0.15.100"},
{"privateDnsName", "ip-10-0-15-100.eu-west-1.compute.internal"},
{"primary", "true"}
]}
]}]},
{"item",
[{"attachment", [{"deviceIndex", "0"}]},
{"association",
[{"publicIp","203.0.113.11"},
{"publicDnsName",
"ec2-203-0-113-11.eu-west-1.compute.amazonaws.com"},
{"ipOwnerId","amazon"}]}]}]},
{"privateIpAddress","10.0.16.29"}]}]}]},
{"item", [{"reservationId","r-006cfdbf8d04c5f01"},
{"ownerId","248536293561"},
{"groupSet",[]},
{"instancesSet",
[{"item",
[{"instanceId","i-1c6d048641f09cad2"},
{"imageId","ami-af4c7989"},
{"instanceState",
[{"code","16"},{"name","running"}]},
{"privateDnsName",
"ip-10-0-16-31.eu-west-1.compute.internal"},
{"dnsName",[]},
{"instanceType","c4.large"},
{"launchTime","2017-04-07T12:05:10"},
{"subnetId","subnet-61ff660"},
{"vpcId","vpc-4fe1562b"},
{"networkInterfaceSet", [
{"item",
[{"attachment", [{"deviceIndex", "0"}]},
{"association",
[{"publicIp","203.0.113.21"},
{"publicDnsName",
"ec2-203-0-113-21.eu-west-1.compute.amazonaws.com"},
{"ipOwnerId","amazon"}]}]},
{"item",
[{"attachment", [{"deviceIndex", "1"}]},
{"association",
[{"publicIp","203.0.113.22"},
{"publicDnsName",
"ec2-203-0-113-22.eu-west-1.compute.amazonaws.com"},
{"ipOwnerId","amazon"}]},
{"privateIpAddressesSet", [
{"item", [
{"privateIpAddress", "10.0.16.31"},
{"privateDnsName", "ip-10-0-16-31.eu-west-1.compute.internal"},
{"primary", "true"}
]}
]}]}]},
{"privateIpAddress","10.0.16.31"}]}]}]}].
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