From 79f68be20771f8ca4034a19f041cb86372470ce1 Mon Sep 17 00:00:00 2001
From: Amaury Denoyelle <adenoyelle@haproxy.com>
Date: Tue, 13 Jul 2021 10:35:50 +0200
Subject: [PATCH] MINOR: srv: do not allow to track a dynamic server

Prevents the use of the "track" keyword for a dynamic server. This
simplifies the deletion of a dynamic server, without having to worry
about servers which might tracked it.

A BUG_ON is present in the dynamic server delete function to validate
this assertion.
---
 src/server.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/server.c b/src/server.c
index 1ad4c2e6a..664e2f4ec 100644
--- a/src/server.c
+++ b/src/server.c
@@ -4627,6 +4627,9 @@ static int cli_parse_delete_server(char **args, char *payload, struct appctx *ap
 		goto out;
 	}
 
+	/* A dynamic server cannot be tracked. */
+	BUG_ON(srv->trackers);
+
 	/* Only servers in maintenance can be deleted. This ensures that the
 	 * server is not present anymore in the lb structures (through
 	 * lbprm.set_server_status_down).
@@ -4764,6 +4767,12 @@ int srv_apply_track(struct server *srv, struct proxy *curproxy)
 		return 1;
 	}
 
+	if (strack->flags & SRV_F_DYNAMIC) {
+		ha_alert("unable to use %s/%s for tracking as it is a dynamic server.\n",
+		         px->id, strack->id);
+		return 1;
+	}
+
 	if (!strack->do_check && !strack->do_agent && !strack->track &&
 	    !strack->trackit) {
 		ha_alert("unable to use %s/%s for "