fix(healthcheck): probe domain nodes by node domain, not resolved ip

apisix/healthcheck_manager.lua

@@ -57,11 +57,15 @@ local function compute_targets(up_conf)
     local host = up_conf.checks and up_conf.checks.active and up_conf.checks.active.host
     local port = up_conf.checks and up_conf.checks.active and up_conf.checks.active.port
     local up_hdr = up_conf.pass_host == "rewrite" and up_conf.upstream_host
-    local use_node_hdr = up_conf.pass_host == "node" or nil
 
     local targets = {}
     for _, node in ipairs(up_conf.nodes) do
-        local host_hdr = up_hdr or (use_node_hdr and node.domain) or nil
+        -- A health check has no client; the gateway probes the node by the node's own
+        -- identity (its domain), so use node.domain as the Host header regardless of
+        -- pass_host (except "rewrite", which pins an explicit Host). Otherwise a domain
+        -- node probes with the resolved ip as Host/SNI, breaking HTTPS health checks.
+        -- node.domain is nil for ip nodes.
+        local host_hdr = up_hdr or node.domain
         local target_port = port or node.port
         -- add_target defaults the hostname to the ip when checks.active.host is
         -- unset, so mirror that here to match the shm entry's stored hostname

t/node/healthcheck-node-domain-host.t

@@ -0,0 +1,190 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+use t::APISIX 'no_plan';
+
+repeat_each(1);
+log_level('info');
+no_root_location();
+no_shuffle();
+
+add_block_preprocessor(sub {
+    my ($block) = @_;
+
+    if (!$block->http_config) {
+        # probe targets that log what the active health checker actually sends:
+        # the Host header over HTTP, and the TLS SNI over HTTPS.
+        my $http_config = <<'_EOC_';
+server {
+    listen 1988;
+    location /healthz {
+        content_by_lua_block {
+            ngx.log(ngx.WARN, "probe Host: ", ngx.var.http_host)
+            ngx.say("ok")
+        }
+    }
+}
+
+server {
+    listen 1989 ssl;
+    ssl_certificate ../../certs/apisix.crt;
+    ssl_certificate_key ../../certs/apisix.key;
+    location /healthz {
+        content_by_lua_block {
+            ngx.log(ngx.WARN, "probe SNI: ", ngx.var.ssl_server_name)
+            ngx.say("ok")
+        }
+    }
+}
+_EOC_
+        $block->set_value("http_config", $http_config);
+    }
+
+    if (!$block->request) {
+        $block->set_value("request", "GET /t");
+    }
+});
+
+run_tests();
+
+__DATA__
+
+=== TEST 1: domain node with the default pass_host is probed with the node domain as Host
+--- config
+    location /t {
+        content_by_lua_block {
+            local core = require("apisix.core")
+            local original_parse_domain = core.resolver.parse_domain
+            core.resolver.parse_domain = function(domain)
+                if domain == "test.com" then
+                    return "127.0.0.1", nil
+                end
+                return original_parse_domain(domain)
+            end
+
+            local t = require("lib.test_admin").test
+            local code = t('/apisix/admin/upstreams/1',
+                ngx.HTTP_PUT,
+                [[{
+                    "type": "roundrobin",
+                    "nodes": { "test.com:1988": 1 },
+                    "checks": {
+                        "active": {
+                            "http_path": "/healthz",
+                            "healthy": { "interval": 1, "successes": 1 },
+                            "unhealthy": { "interval": 1, "http_failures": 1 }
+                        }
+                    }
+                }]]
+            )
+            if code >= 300 then
+                ngx.status = code
+                return
+            end
+
+            code = t('/apisix/admin/routes/1',
+                ngx.HTTP_PUT,
+                [[{ "uri": "/hello", "upstream_id": "1" }]]
+            )
+            if code >= 300 then
+                ngx.status = code
+                return
+            end
+
+            local http = require "resty.http"
+            local httpc = http.new()
+            httpc:request_uri("http://127.0.0.1:" .. ngx.var.server_port .. "/hello",
+                              {method = "GET", keepalive = false})
+
+            ngx.sleep(2)
+
+            core.resolver.parse_domain = original_parse_domain
+            ngx.say("done")
+        }
+    }
+--- response_body
+done
+--- error_log
+probe Host: test.com
+--- no_error_log
+probe Host: 127.0.0.1
+--- timeout: 5
+
+
+
+=== TEST 2: over HTTPS, the domain node is probed with the node domain as SNI (not the resolved ip)
+--- config
+    location /t {
+        content_by_lua_block {
+            local core = require("apisix.core")
+            local original_parse_domain = core.resolver.parse_domain
+            core.resolver.parse_domain = function(domain)
+                if domain == "test.com" then
+                    return "127.0.0.1", nil
+                end
+                return original_parse_domain(domain)
+            end
+
+            local t = require("lib.test_admin").test
+            local code = t('/apisix/admin/upstreams/1',
+                ngx.HTTP_PUT,
+                [[{
+                    "type": "roundrobin",
+                    "scheme": "https",
+                    "nodes": { "test.com:1989": 1 },
+                    "checks": {
+                        "active": {
+                            "type": "https",
+                            "http_path": "/healthz",
+                            "https_verify_certificate": false,
+                            "healthy": { "interval": 1, "successes": 1 },
+                            "unhealthy": { "interval": 1, "http_failures": 1 }
+                        }
+                    }
+                }]]
+            )
+            if code >= 300 then
+                ngx.status = code
+                return
+            end
+
+            code = t('/apisix/admin/routes/1',
+                ngx.HTTP_PUT,
+                [[{ "uri": "/hello", "upstream_id": "1" }]]
+            )
+            if code >= 300 then
+                ngx.status = code
+                return
+            end
+
+            local http = require "resty.http"
+            local httpc = http.new()
+            httpc:request_uri("http://127.0.0.1:" .. ngx.var.server_port .. "/hello",
+                              {method = "GET", keepalive = false})
+
+            ngx.sleep(2)
+
+            core.resolver.parse_domain = original_parse_domain
+            ngx.say("done")
+        }
+    }
+--- response_body
+done
+--- error_log
+probe SNI: test.com
+--- no_error_log
+probe SNI: 127.0.0.1
+--- timeout: 5