agent-check
Enable an auxiliary agent check which is run independently of a regular
- health check. An agent health check is performed by making a TCP
- connection to the port set by the "agent-port" parameter" and reading
- an ASCII string. The string should have one of the following forms:
-
- * An ASCII representation of an positive integer percentage.
- e.g. "75%"
+ health check. An agent health check is performed by making a TCP connection
+ to the port set by the "agent-port" parameter and reading an ASCII string.
+ The string is made of a series of words delimited by spaces, tabs or commas
+ in any order, optionally terminated by '\r' and/or '\n', each consisting of :
+ - An ASCII representation of a positive integer percentage, e.g. "75%".
Values in this format will set the weight proportional to the initial
weight of a server as configured when haproxy starts.
- * The string "drain".
-
- This will cause the weight of a server to be set to 0, and thus it will
- not accept any new connections other than those that are accepted via
- persistence.
-
- * The string "down", optionally followed by a description string.
-
- Mark the server as down and log the description string as the reason.
-
- * The string "stopped", optionally followed by a description string.
-
- This currently has the same behaviour as "down".
-
- * The string "fail", optionally followed by a description string.
-
- This currently has the same behaviour as "down".
+ - The word "ready". This will turn the server's administrative state to the
+ READY mode, thus cancelling any DRAIN or MAINT state
+
+ - The word "drain". This will turn the server's administrative state to the
+ DRAIN mode, thus it will not accept any new connections other than those
+ that are accepted via persistence.
+
+ - The word "maint". This will turn the server's administrative state to the
+ MAINT mode, thus it will not accept any new connections at all, and health
+ checks will be stopped.
+
+ - The words "down", "failed", or "stopped", optionally followed by a
+ description string after a sharp ('#'). All of these mark the server's
+ operating state as DOWN, but since the word itself is reported on the stats
+ page, the difference allows an administrator to know if the situation was
+ expected or not : the service may intentionally be stopped, may appear up
+ but fail some validity tests, or may be seen as down (eg: missing process,
+ or port not responding).
+
+ - The word "up" sets back the server's operating state as UP if health checks
+ also report that the service is accessible.
+
+ Parameters which are not advertised by the agent are not changed. For
+ example, an agent might be designed to monitor CPU usage and only report a
+ relative weight and never interact with the operating status. Similarly, an
+ agent could be designed as an end-user interface with 3 radio buttons
+ allowing an administrator to change only the administrative state. However,
+ it is important to consider that only the agent may revert its own actions,
+ so if a server is set to DRAIN mode or to DOWN state using the agent, the
+ agent must implement the other equivalent actions to bring the service into
+ operations again.
Failure to connect to the agent is not considered an error as connectivity
is tested by the regular health check which is enabled by the "check"
- parameter.
+ parameter. Warning though, it is not a good idea to stop an agent after it
+ reports "down", since only an agent reporting "up" will be able to turn the
+ server up again. Note that the CLI on the Unix stats socket is also able to
+ force an agent's result in order to workaround a bogus agent if needed.
- Requires the ""agent-port" parameter to be set.
- See also the "agent-check" parameter.
+ Requires the "agent-port" parameter to be set. See also the "agent-inter"
+ parameter.
Supported in default-server: No
break;
case PR_O2_LB_AGENT_CHK: {
- short status = HCHK_STATUS_L7RSP;
- const char *desc = "Unknown feedback string";
- const char *down_cmd = NULL;
- int disabled;
- char *p;
+ int status = HCHK_STATUS_CHECKED;
+ const char *hs = NULL; /* health status */
+ const char *as = NULL; /* admin status */
+ const char *ps = NULL; /* performance status */
+ const char *err = NULL; /* first error to report */
+ const char *wrn = NULL; /* first warning to report */
+ char *cmd, *p;
+
+ /* We're getting an agent check response. The agent could
+ * have been disabled in the mean time with a long check
+ * still pending. It is important that we ignore the whole
+ * response.
+ */
+ if (!(check->server->agent.state & CHK_ST_ENABLED))
+ break;
+
+ /* The agent supports strings made of a single line ended by the
+ * first CR ('\r') or LF ('\n'). This line is composed of words
+ * delimited by spaces (' '), tabs ('\t'), or commas (','). The
+ * line may optionally contained a description of a state change
+ * after a sharp ('#'), which is only considered if a health state
+ * is announced.
+ *
+ * Words may be composed of :
+ * - a numeric weight suffixed by the percent character ('%').
+ * - a health status among "up", "down", "stopped", and "fail".
+ * - an admin status among "ready", "drain", "maint".
+ *
+ * These words may appear in any order. If multiple words of the
+ * same category appear, the last one wins.
+ */
- /* get a complete line first */
p = check->bi->data;
while (*p && *p != '\n' && *p != '\r')
p++;
set_server_check_status(check, check->status, "Ignoring incomplete line from agent");
break;
}
+
*p = 0;
+ cmd = check->bi->data;
- /*
- * The agent may have been disabled after a check was
- * initialised. If so, ignore weight changes and drain
- * settings from the agent. Note that the setting is
- * always present in the state of the agent the server,
- * regardless of if the agent is being run as a primary or
- * secondary check. That is, regardless of if the check
- * parameter of this function is the agent or check field
- * of the server.
- */
- disabled = !(check->server->agent.state & CHK_ST_ENABLED);
+ while (*cmd) {
+ /* look for next word */
+ if (*cmd == ' ' || *cmd == '\t' || *cmd == ',') {
+ cmd++;
+ continue;
+ }
- if (strchr(check->bi->data, '%')) {
- if (disabled)
+ if (*cmd == '#') {
+ /* this is the beginning of a health status description,
+ * skip the sharp and blanks.
+ */
+ cmd++;
+ while (*cmd == '\t' || *cmd == ' ')
+ cmd++;
break;
- desc = server_parse_weight_change_request(s, check->bi->data);
- if (!desc) {
- status = HCHK_STATUS_L7OKD;
- desc = check->bi->data;
}
- } else if (!strcasecmp(check->bi->data, "drain")) {
- if (disabled)
- break;
- desc = server_parse_weight_change_request(s, "0%");
- if (!desc) {
- desc = "drain";
+
+ /* find the end of the word so that we have a null-terminated
+ * word between <cmd> and <p>.
+ */
+ p = cmd + 1;
+ while (*p && *p != '\t' && *p != ' ' && *p != '\n' && *p != ',')
+ p++;
+ if (*p)
+ *p++ = 0;
+
+ /* first, health statuses */
+ if (strcasecmp(cmd, "up") == 0) {
+ check->health = check->rise + check->fall - 1;
status = HCHK_STATUS_L7OKD;
+ hs = cmd;
+ }
+ else if (strcasecmp(cmd, "down") == 0) {
+ check->health = 0;
+ status = HCHK_STATUS_L7STS;
+ hs = cmd;
+ }
+ else if (strcasecmp(cmd, "stopped") == 0) {
+ check->health = 0;
+ status = HCHK_STATUS_L7STS;
+ hs = cmd;
+ }
+ else if (strcasecmp(cmd, "fail") == 0) {
+ check->health = 0;
+ status = HCHK_STATUS_L7STS;
+ hs = cmd;
}
- } else if (!strncasecmp(check->bi->data, "down", strlen("down"))) {
- down_cmd = "down";
- } else if (!strncasecmp(check->bi->data, "stopped", strlen("stopped"))) {
- down_cmd = "stopped";
- } else if (!strncasecmp(check->bi->data, "fail", strlen("fail"))) {
- down_cmd = "fail";
+ /* admin statuses */
+ else if (strcasecmp(cmd, "ready") == 0) {
+ as = cmd;
+ }
+ else if (strcasecmp(cmd, "drain") == 0) {
+ as = cmd;
+ }
+ else if (strcasecmp(cmd, "maint") == 0) {
+ as = cmd;
+ }
+ /* else try to parse a weight here and keep the last one */
+ else if (isdigit((unsigned char)*cmd) && strchr(cmd, '%') != NULL) {
+ ps = cmd;
+ }
+ else {
+ /* keep a copy of the first error */
+ if (!err)
+ err = cmd;
+ }
+ /* skip to next word */
+ cmd = p;
+ }
+ /* here, cmd points either to \0 or to the beginning of a
+ * description. Skip possible leading spaces.
+ */
+ while (*cmd == ' ' || *cmd == '\n')
+ cmd++;
+
+ /* First, update the admin status so that we avoid sending other
+ * possibly useless warnings and can also update the health if
+ * present after going back up.
+ */
+ if (as) {
+ if (strcasecmp(as, "drain") == 0)
+ srv_adm_set_drain(check->server);
+ else if (strcasecmp(as, "maint") == 0)
+ srv_adm_set_maint(check->server);
+ else
+ srv_adm_set_ready(check->server);
}
- if (down_cmd) {
- const char *end = check->bi->data + strlen(down_cmd);
- /*
- * The command keyword must terminated the string or
- * be followed by a blank.
+ /* now change weights */
+ if (ps) {
+ const char *msg;
+
+ msg = server_parse_weight_change_request(s, ps);
+ if (!wrn || !*wrn)
+ wrn = msg;
+ }
+
+ /* and finally health status */
+ if (hs) {
+ /* We'll report some of the warnings and errors we have
+ * here. Down reports are critical, we leave them untouched.
+ * Lack of report, or report of 'UP' leaves the room for
+ * ERR first, then WARN.
*/
- if (end[0] == '\0' || end[0] == ' ' || end[0] == '\t') {
- status = HCHK_STATUS_L7STS;
- desc = check->bi->data;
+ const char *msg = cmd;
+ struct chunk *t;
+
+ if (!*msg || status == HCHK_STATUS_L7OKD) {
+ if (err && *err)
+ msg = err;
+ else if (wrn && *wrn)
+ msg = wrn;
}
+
+ t = get_trash_chunk();
+ chunk_printf(t, "via agent : %s%s%s%s",
+ hs, *msg ? " (" : "",
+ msg, *msg ? ")" : "");
+
+ set_server_check_status(check, status, t->str);
}
+ else if (err && *err) {
+ /* No status change but we'd like to report something odd.
+ * Just report the current state and copy the message.
+ */
+ chunk_printf(&trash, "agent reports an error : %s", err);
+ set_server_check_status(check, status/*check->status*/, trash.str);
- set_server_check_status(check, status, desc);
+ }
+ else if (wrn && *wrn) {
+ /* No status change but we'd like to report something odd.
+ * Just report the current state and copy the message.
+ */
+ chunk_printf(&trash, "agent warns : %s", wrn);
+ set_server_check_status(check, status/*check->status*/, trash.str);
+ }
+ else
+ set_server_check_status(check, status, NULL);
break;
}
projects / thirdparty / haproxy.git / commitdiff
