wklken opened a new issue, #12436:
URL: https://github.com/apache/apisix/issues/12436
### Current Behavior
In some condition, when the ip of the domain changed, the apisix keep use
the old ip, cause 504 gateway timeout.
And it would never resume, until do `apisix reload`
At the same time, dig and nslookup command return the newest ip.
### Expected Behavior
apisix should detect the ip changed
### Error Logs
```
2025/07/16 09:41:20 [error] 6290#6290: *554164 [lua] upstream.lua:65:
parse_domain_for_nodes(): parse_domain_for_nodes:
[{"weight":100,"host":"10.105.226.135","domain":"httpbin","priority":1,"upstream_host":"httpbin","port":80}],
client: 10.244.2.240, server: _, request: "GET /api/apigw/prod/anything
HTTP/1.1", host: "bkapi.paasv3-dev.woa.com"
2025/07/16 09:41:20 [error] 6290#6290: *554164 [lua] upstream.lua:69:
parse_domain_for_nodes(): parse_domain_for_nodes: host=10.105.226.135, client:
10.244.2.240, server: _, request: "GET /api/apigw/prod/anything HTTP/1.1",
host: "bkapi.paasv3-dev.woa.com"
2025/07/16 09:41:20 [error] 6290#6290: *554164 [lua] upstream.lua:84:
parse_domain_for_nodes(): parse_domain_for_nodes: add the node back, client:
10.244.2.240, server: _, request: "GET /api/apigw/prod/anything HTTP/1.1",
host: "bkapi.paasv3-dev.woa.com"
2025/07/16 09:41:20 [error] 6290#6290: *554164 [lua] init.lua:213:
parse_domain_in_route(): parse_domain_in_route |
new_nodes=[{"weight":100,"host":"10.105.226.135","domain":"httpbin","priority":1,"upstream_host":"httpbin","port":80}],
client: 10.244.2.240, server: _, request: "GET /api/apigw/prod/anything
HTTP/1.1", host: "bkapi.paasv3-dev.woa.com"
2025/07/16 09:41:20 [error] 6290#6290: *554164 [lua] init.lua:219:
parse_domain_in_route(): parse_domain_in_route |
up_conf:{"timeout":{"send":30,"connect":30,"read":30},"hash_on":"vars","type":"roundrobin","parent":{"update_count":0,"modifiedIndex":5360,"orig_modifiedIndex":5360,"clean_handlers":{},"createdIndex":5360,"has_domain":true,"key":"/bk-gateway-apisix/routes/apigw.prod.2347","value":{"timeout":{"send":30,"connect":30,"read":30},"desc":"Returns
anything passed in request
data.","name":"apigw-prod-anything-get","labels":{"gateway.bk.tencent.com/stage":"prod","gateway.bk.tencent.com/gateway":"apigw"},"update_time":1752566944,"plugins":{"bk-proxy-rewrite":{"match_subpath":false,"uri":"/anything","subpath_param_name":":ext","method":"GET","use_real_request_uri_unsafe":false},"bk-resource-context":{"bk_resource_name":"anything_get","bk_resource_id":2347,"bk_resource_auth":{"verified_user_required":false,"resource_perm_required":false,"skip_user_verification":false,"verified_a
pp_required":false},"bk_resource_auth_obj":{"verified_user_required":false,"resource_perm_required":false,"skip_user_verification":false,"verified_app_required":false}}},"uris":["/api/apigw/prod/anything","/api/apigw/prod/anything/"],"upstream":{"timeout":"table:
0x7f119b810dd0","hash_on":"vars","type":"roundrobin","parent":"table:
0x7f1199322a98","original_nodes":[{"weight":100,"host":"10.105.226.135","domain":"httpbin","priority":1,"upstream_host":"httpbin","port":80}],"nodes":"table:
0x7f11693587e0","pass_host":"node","scheme":"http","nodes_ref":"table:
0x7f11693587e0"},"status":1,"id":"apigw.prod.2347","service_id":"apigw.prod.stage-4","priority":0,"methods":["GET"],"create_time":1752566944}},"original_nodes":"table:
0x7f11693587e0","nodes":"table:
0x7f11693587e0","pass_host":"node","scheme":"http","nodes_ref":"table:
0x7f11693587e0"}, client: 10.244.2.240, server: _, request: "GET
/api/apigw/prod/anything HTTP/1.1", host: "bkapi.paasv3-dev.woa.com"
2025/07/16 09:41:20 [error] 6290#6290: *554164 [lua] init.lua:221:
parse_domain_in_route(): parse_domain_in_route | compare result:true, client:
10.244.2.240, server: _, request: "GET /api/apigw/prod/anything HTTP/1.1",
host: "bkapi.paasv3-dev.woa.com"
2025/07/16 09:41:20 [error] 6290#6290: *554164 [lua] init.lua:223:
parse_domain_in_route(): parse_domain_in_route | no change, use old route,
client: 10.244.2.240, server: _, request: "GET /api/apigw/prod/anything
HTTP/1.1", host: "bkapi.paasv3-dev.woa.com"
```
### Steps to Reproduce
1. add a route with `route.upstream.nodes` and the `nodes[0].host =
httpbin`, which is a svc in k8s, route to the httpbin service
```
$ curl -H "X-API-KEY: $admin_key"
http://127.0.0.1:9180/apisix/admin/routes/apigw.prod.2347 | jq
{
"key": "/bk-gateway-apisix/routes/apigw.prod.2347",
"modifiedIndex": 5360,
"createdIndex": 5360,
"value": {
"timeout": {
"send": 30,
"connect": 30,
"read": 30
},
"desc": "Returns anything passed in request data.",
"name": "apigw-prod-anything-get",
"update_time": 1752566944,
"plugins": {
"proxy-rewrite": {
"method": "GET",
"uri": "/anything"
}
},
"create_time": 1752566944,
"upstream": {
"timeout": {
"send": 30,
"connect": 30,
"read": 30
},
"nodes": [
{
"weight": 100,
"priority": 1,
"port": 80,
"host": "httpbin"
}
],
"pass_host": "node",
"scheme": "http",
"type": "roundrobin"
},
"labels": {
"gateway.bk.tencent.com/stage": "prod",
"gateway.bk.tencent.com/gateway": "apigw"
},
"id": "apigw.prod.2347",
"service_id": "apigw.prod.stage-4",
"status": 1,
"methods": [
"GET"
],
"uris": [
"/api/apigw/prod/anything",
"/api/apigw/prod/anything/"
]
}
}
```
here, the route.upstream.nodes[0].host = httpbin`
2. add `core.log.error` for debug
apisix/init.lua
```lua
local function parse_domain_in_route(route)
local nodes = route.value.upstream.nodes
local new_nodes, err = upstream_util.parse_domain_for_nodes(nodes)
core.log.error("parse_domain_in_route | new_nodes=",
core.json.delay_encode(new_nodes, true))
if not new_nodes then
return nil, err
end
local up_conf = route.dns_value and route.dns_value.upstream
core.log.error("parse_domain_in_route | up_conf:",
core.json.delay_encode(up_conf, true))
local ok = upstream_util.compare_upstream_node(up_conf, new_nodes)
core.log.error("parse_domain_in_route | compare result:", ok)
if ok then
core.log.error("parse_domain_in_route | no change, use old route")
return route
end
-- don't modify the modifiedIndex to avoid plugin cache miss because of
DNS resolve result
-- has changed
-- Here we copy the whole route instead of part of it,
-- so that we can avoid going back from route.value to route during
copying.
route.dns_value = core.table.deepcopy(route).value
route.dns_value.upstream.nodes = new_nodes
core.log.info("parse route which contain domain: ",
core.json.delay_encode(route, true))
return route
end
```
and
apisix/utils/upstream.lua
```lua
local function parse_domain_for_nodes(nodes)
core.log.error("parse_domain_for_nodes: ", core.json.delay_encode(nodes,
true))
local new_nodes = core.table.new(#nodes, 0)
for _, node in ipairs(nodes) do
local host = node.host
core.log.error("parse_domain_for_nodes: host=", host)
if not ipmatcher.parse_ipv4(host) and
not ipmatcher.parse_ipv6(host) then
local ip, err = core.resolver.parse_domain(host)
if ip then
local new_node = core.table.clone(node)
new_node.host = ip
new_node.domain = host
core.table.insert(new_nodes, new_node)
end
if err then
core.log.error("dns resolver domain: ", host, " error: ",
err)
end
else
core.log.error("parse_domain_for_nodes: add the node back")
core.table.insert(new_nodes, node)
end
end
return new_nodes
end
_M.parse_domain_for_nodes = parse_domain_for_nodes
```
5. apisix reload and update routes in etcd, trigger `config_etcd.lua:389:
sync_data()`
6. at the same time, delete the httpbin service and kubectl apply it again
(the cluster ip would be changed) 【not 100% Reproducible】
7. curl it
-----
according to the error.log，
1. the `parse_domain-for_nodes` args 1 is
`[{"weight":100,"host":"10.105.226.135","domain":"httpbin","priority":1,"upstream_host":"httpbin","port":80}]`,
the host is a ip here
2025/07/16 09:41:20 [error] 6290#6290: *554164 [lua] upstream.lua:65:
parse_domain_for_nodes(): parse_domain_for_nodes:
[{"weight":100,"host":"10.105.226.135","domain":"httpbin","priority":1,"upstream_host":"httpbin","port":80}],
client: 10.244.2.240, server: _, request: "GET /api/apigw/prod/anything
HTTP/1.1", host: "bkapi.paasv3-dev.woa.com"
2. while it's not a domain, so it would not
`core.resolver.parse_domain(host)`
2025/07/16 09:41:20 [error] 6290#6290: *554164 [lua] upstream.lua:69:
parse_domain_for_nodes(): parse_domain_for_nodes: host=10.105.226.135, client:
10.244.2.240, server: _, request: "GET /api/apigw/prod/anything HTTP/1.1",
host: "bkapi.paasv3-dev.woa.com"
3. then it been added back
2025/07/16 09:41:20 [error] 6290#6290: *554164 [lua] upstream.lua:84:
parse_domain_for_nodes(): parse_domain_for_nodes: add the node back, client:
10.244.2.240, server: _, request: "GET /api/apigw/prod/anything HTTP/1.1",
host: "bkapi.paasv3-dev.woa.com"
------
so the worker would never detect the ip changes, until `apisix reload`
### Environment
- APISIX version (run `apisix version`): 3.2.1
- Operating system (run `uname -a`):
- OpenResty / Nginx version (run `openresty -V` or `nginx -V`):
- etcd version, if relevant (run `curl
http://127.0.0.1:9090/v1/server_info`):
- APISIX Dashboard version, if relevant:
- Plugin runner version, for issues related to plugin runners:
- LuaRocks version, for installation issues (run `luarocks --version`):
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