BUG/MEDIUM: connections: force connections cleanup on server changes
I've been trying to understand a change of behaviour between v2.2dev5 and
v2.2dev6. Indeed our probe is regularly testing to add and remove
servers on a given backend such as:
# echo "show servers state be_foo" | sudo socat stdio /var/lib/haproxy/stats
113 be_foo 1 srv0 10.236.139.34 2 0 1 1 263 15 3 4 6 0 0 0 - 31255 -
113 be_foo 2 srv1 0.0.0.0 0 1 256 256 0 15 3 0 14 0 0 0 - 0 -
-> curl on the corresponding frontend: reply from server:31255
# echo "set server be_foo/srv1 addr 10.236.139.34 port 31257" | sudo socat stdio /var/lib/haproxy/stats
IP changed from '0.0.0.0' to '10.236.139.34', port changed from '0' to '31257' by 'stats socket command'
# echo "set server be_foo/srv1 weight 256" | sudo socat stdio /var/lib/haproxy/stats
# echo "set server be_foo/srv1 check-port 8500" | sudo socat stdio /var/lib/haproxy/stats
health check port updated.
# echo "set server be_foo/srv1 state ready" | sudo socat stdio /var/lib/haproxy/stats
# echo "show servers state be_foo" | sudo socat stdio /var/lib/haproxy/stats
113 be_foo 1 srv0 10.236.139.34 2 0 1 1 105 15 3 4 6 0 0 0 - 31255 -
113 be_foo 2 srv1 10.236.139.34 2 0 256 256 2319 15 3 2 6 0 0 0 - 31257 -
-> curl on the corresponding frontend: reply for server:31257
(notice the difference of weight)
# echo "set server be_foo/srv1 state maint" | sudo socat stdio /var/lib/haproxy/stats
# echo "set server be_foo/srv1 addr 0.0.0.0 port 0" | sudo socat stdio /var/lib/haproxy/stats
IP changed from '10.236.139.34' to '0.0.0.0', port changed from '31257' to '0' by 'stats socket command'
# echo "show servers state be_foo" | sudo socat stdio /var/lib/haproxy/stats
113 be_foo 1 srv0 10.236.139.34 2 0 1 1 263 15 3 4 6 0 0 0 - 31255 -
113 be_foo 2 srv1 0.0.0.0 0 1 256 256 0 15 3 0 14 0 0 0 - 0 -
-> curl on the corresponding frontend: reply from server:31255
# echo "set server be_foo/srv1 addr 10.236.139.34 port 31256" | sudo socat stdio /var/lib/haproxy/stats
IP changed from '0.0.0.0' to '10.236.139.34', port changed from '0' to '31256' by 'stats socket command'
# echo "set server be_foo/srv1 weight 256" | sudo socat stdio /var/lib/haproxy/stats
# echo "set server be_foo/srv1 check-port 8500" | sudo socat stdio /var/lib/haproxy/stats
health check port updated.
# echo "set server be_foo/srv1 state ready" | sudo socat stdio /var/lib/haproxy/stats
# echo "show servers state be_foo" | sudo socat stdio /var/lib/haproxy/stats
113 be_foo 1 srv0 10.236.139.34 2 0 1 1 105 15 3 4 6 0 0 0 - 31255 -
113 be_foo 2 srv1 10.236.139.34 2 0 256 256 2319 15 3 2 6 0 0 0 - 31256 -
-> curl on the corresponding frontend: reply from server:31257 (!)
Here we indeed would expect to get an anver from server:31256. The issue
is highly linked to the usage of `pool-purge-delay`, with a value which
is higher than the duration of the test, 10s in our case.
a git bisect between dev5 and dev6 seems to show commit
079cb9af22da6 ("MEDIUM: connections: Revamp the way idle connections are killed")
being the origin of this new behaviour.
So if I understand the later correctly, it seems that it was more a
matter of chance that we did not saw the issue earlier.
My patch proposes to force clean idle connections in the two following
cases:
- we set a (still running) server to maintenance
- we change the ip/port of a server
This commit should be backported to 2.1, 2.0, and 1.9.
Signed-off-by: William Dauchy <w.dauchy@criteo.com>
diff --git a/src/server.c b/src/server.c
index 4d5e706..94e7aee 100644
--- a/src/server.c
+++ b/src/server.c
@@ -55,6 +55,7 @@
static int srv_set_fqdn(struct server *srv, const char *fqdn, int dns_locked);
static void srv_state_parse_line(char *buf, const int version, char **params, char **srv_params);
static int srv_state_get_version(FILE *f);
+static void srv_cleanup_connections(struct server *srv);
/* List head of all known server keywords */
static struct srv_kw_list srv_keywords = {
@@ -3669,8 +3670,11 @@
}
out:
- if (changed)
+ if (changed) {
+ /* force connection cleanup on the given server */
+ srv_cleanup_connections(s);
srv_set_dyncookie(s);
+ }
if (updater)
chunk_appendf(msg, " by '%s'", updater);
chunk_appendf(msg, "\n");
@@ -4832,6 +4836,8 @@
if (s->onmarkeddown & HANA_ONMARKEDDOWN_SHUTDOWNSESSIONS)
srv_shutdown_streams(s, SF_ERR_DOWN);
+ /* force connection cleanup on the given server */
+ srv_cleanup_connections(s);
/* we might have streams queued on this server and waiting for
* a connection. Those which are redispatchable will be queued
* to another server or to the proxy itself.
@@ -5160,6 +5166,37 @@
return task;
}
+/* cleanup connections for a given server
+ * might be useful when going on forced maintenance or live changing ip/port
+ */
+void srv_cleanup_connections(struct server *srv)
+{
+ struct connection *conn;
+ int did_remove;
+ int i;
+ int j;
+
+ HA_SPIN_LOCK(OTHER_LOCK, &idle_conn_srv_lock);
+ for (i = 0; i < global.nbthread; i++) {
+ did_remove = 0;
+ HA_SPIN_LOCK(OTHER_LOCK, &toremove_lock[i]);
+ for (j = 0; j < srv->curr_idle_conns; j++) {
+ conn = MT_LIST_POP(&srv->idle_conns[i], struct connection *, list);
+ if (!conn)
+ conn = MT_LIST_POP(&srv->safe_conns[i],
+ struct connection *, list);
+ if (!conn)
+ break;
+ did_remove = 1;
+ MT_LIST_ADDQ(&toremove_connections[i], (struct mt_list *)&conn->list);
+ }
+ HA_SPIN_UNLOCK(OTHER_LOCK, &toremove_lock[i]);
+ if (did_remove)
+ task_wakeup(idle_conn_cleanup[i], TASK_WOKEN_OTHER);
+ }
+ HA_SPIN_UNLOCK(OTHER_LOCK, &idle_conn_srv_lock);
+}
+
struct task *srv_cleanup_idle_connections(struct task *task, void *context, unsigned short state)
{
struct server *srv;